Cisco ACNS Software Configuration Guide for Centrally Managed Deployments, Release 5.2 - Chapter 5: Configuring the ACNS Network for Content Distribution [Cisco Application and Content Networking System (ACNS) Software]

Table Of Contents

Configuring the ACNS Network for Content Distribution

Preparing for Channel Distribution of Content

Creating and Modifying Locations

Configuring Channel Elements

Creating and Modifying Content Providers

Deleting Content Providers

Creating and Modifying Websites

Deleting Websites

Configuring Channels for Channel Distribution

Creating and Modifying Channels

Creating a Channel

Modifying a Channel

Designating the Root Content Engine

Adding and Removing Content Engines from Channels

Adding and Removing Device Groups from Channels

Deleting Channels

Viewing Channels

Distributing Content Through Unicast Replication

Configuring Location Leader Preference and Forwarder Selection Probability

Configuring the Forwarder Lookup Level

Configuring the Content Metadata Poll Interval Multiplier

Commands Related to Distribution Settings

Distributing Content Through Multicast Replication

About IP Multicasting

About Multicast Clouds

About Configuring Carousel Passes

About the NACK Interval Multiplier

About the File Resend or Stop Feature

About Configuring Multicast Forward Error Correction

About Configuring the Multicast Sender Delay Interval

Configuring PGM and File Transmission Parameters Using Multicast Expert Mode

About Configuring Channel Options for Content Replication

Enabling Content Engines for Multicasting

Configuring Multicast Cloud Properties

Modifying a Multicast Cloud

Deleting Multicast Clouds

Viewing Multicast Clouds

Assigning Content Engines to a Multicast Cloud

Assigning and Removing Multicast Clouds from Channels

Verifying the Multicast Configuration

Commands Related to Multicasting

Multicast Sender Interoperability Issues

Where to Go Next

Configuring the ACNS Network for Content Distribution

Once the hardware devices that make up your ACNS network are properly installed and configured, you are ready to use the information contained in this chapter to organize those devices into an ACNS network that is capable of serving pre-positioned content or live media to end users.

In the ACNS network, content is replicated through a channel distribution architecture. Content in channels can be transmitted by unicast pull or, if multicasting is enabled, by multicast push. This chapter provides information about configuring the network elements for channel distribution and multicasting. It contains the following sections:

•Preparing for Channel Distribution of Content

•Configuring Channel Elements

•Configuring Channels for Channel Distribution

•Distributing Content Through Unicast Replication

•Distributing Content Through Multicast Replication

•Where to Go Next

Figure 5-1 shows the task flow for configuring channels for unicast and multicast content distribution.

Figure 5-1 Distributing Content in the ACNS Network

Preparing for Channel Distribution of Content

Channel distribution describes the manner in which content is distributed from the origin web server to all the Content Engines that are subscribed to the content, or more specifically, assigned to the channel that represents that group of content objects. (For an overview of the channel distribution architecture, see the "Content Acquisition and Distribution Architecture" section.)

In preparing for channel distribution of content, you should configure the following network elements in this order:

1. Locations—Creating and Modifying Locations

2. Content providers—Creating and Modifying Content Providers

3. Websites—Creating and Modifying Websites

4. Channels—Creating and Modifying Channels

Creating and Modifying Locations

Locations are set up in the Content Distribution Manager GUI, and they organize and group Content Engines into virtual networks for distribution of content through channels.

Locations need to be configured before you can activate Content Engines and Content Routers and bring them online in the ACNS network. A default location is created automatically when you use the Content Distribution Manager Quick Start tool to activate your devices. If you wish to create a new location or modify the default location, use the procedure in this section.

Note For more information on working with locations, see the "Working with Device Locations" section.

To create a new location, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Locations. The Locations window appears. (See Figure 5-2.)

Figure 5-2 Locations Window

Step 2 Click the Create New Location icon in the taskbar. The Creating New Location window appears. (See Figure 5-3.)

Figure 5-3 Creating New Location Window

Step 3 Enter a location name in the Name field.

Step 4 Choose a parent location (or choose None) from the Parent Location drop-down list.

A location with no parent location assigned is a level 1 location. A location with a level 1 parent becomes a level 2 location, and so forth. The location level is displayed after you choose a parent location (or choose None) and click Submit to save the configuration.

Step 5 If you wish, enter comments about the location in the Comments field.

Step 6 Click Submit.

To modify an existing location, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Locations. The Locations window appears. (See Figure 5-2.)

Step 2 Click the Edit icon next to the name of the location you want to modify.

Step 3 Change the location name, parent location, or description as needed.

Step 4 Click Submit to save the changes.

Configuring Channel Elements

This section describes how to create and modify content providers and websites. If you wish to associate a company name with its website, you must create a content provider directory listing. Websites must be set up in your ACNS network before you can create channels.

Creating and Modifying Content Providers

When you are creating a channel, you must choose the name of a content provider from the Content Provider drop-down list, or you can choose None. To populate this list, you must create a directory listing with the name, address, and contact information of a content provider. Content provider listings are created in the Content Distribution Manager GUI.

To create a content provider listing, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Create New Channel icon in the taskbar. The Creating New Channel window appears.

Step 3 Click the New Content Provider button in the Channel Information section. The Creating New Content Provider window appears.

Step 4 Enter the company name. You also have the option to enter the address and contact information.

Step 5 Click Submit.

To modify a content provider listing, follow these steps:

Step 1 Choose Content > Channels and click the Edit icon next to the channel for which you want to modify the content provider. The Modifying Channel window appears.

Step 2 Click the Edit Content Provider button. The Modifying Content Provider window appears. (See Figure 5-4.)

Figure 5-4 Modifying Content Provider Window

Step 3 Enter any changes you want to make to the company name and address, the primary contact information, or the optional secondary contact information.

Note Clicking Cancel returns you to the Modifying Channel window.

Step 4 Click Submit.

Deleting Content Providers

You can delete content providers as needed.

Note When you delete a content provider, all websites and channels that have been added for the content provider are also deleted.

To delete a content provider, follow these steps:

Step 1 Choose Content > Channels and click the Edit icon next to the channel for which you want to delete the content provider. The Modifying Channel window appears.

Click the Edit Content Provider button. The Modifying Content Provider window appears. (See Figure 5-4.)

Step 2 Click the Trash icon. You are prompted to confirm your decision.

Step 3 Click OK to execute your request.

Creating and Modifying Websites

Websites must be defined in your ACNS network before you can create channels. Channels then map the website content to the Content Engines in your ACNS network. The Content Distribution Manager GUI allows you to define websites in your ACNS network. A website listing must provide the URL for the origin web server that stores the website content.

To create a website, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels. The Channels window appears.

Step 2 Click the Create New Channel icon in the task bar. The Creating New Channel window appears.

Step 3 To create a new website, click the New Website button in the Creating New Channel window. The Creating New Web Site window appears. (See Figure 5-5.)

Figure 5-5 Creating New Web Site Window

Step 4 Enter the name, content provider (or choose None), and origin server for the website. (See Table 5-1 for a description of website properties.)

Table 5-1 Website Properties

Property

Description

Name*¹

Unique name for the website.

Content Provider*

Name of the company that is providing the content. The default is None.

Note The content provider must be predefined in the Creating New Content Provider window. (See the "Creating and Modifying Content Providers" section.)

Origin Server*

Fully qualified domain name of the origin server where the content resides.

Request Routed FQDN

Fully qualified domain name to route requests when using a Content Router.

WMT Authentication Type

Basic authentication or NTLM authentication.

Note This setting must match the setting on the origin server for the stream to play correctly.

Pure DNS Routing

When checked, uses only the DNS server specified in the incoming packets for DNS requests. This causes the DNS caching name service to determine the original destination IP address.

When unchecked (the default), allows the DNS caching name service to use the servers configured on the Content Engine and allows WCCP interception of DNS requests.

Ignore case of URLs during playback

When checked, allows case-insensitive URL matching during the playback of pre-positioned content.

¹* = required field. All other fields are optional.

Step 5 If you wish, choose a WMT authentication type from the WMT Authentication Type drop-down list.

Note This setting must match the setting on the origin server for the stream to play correctly.

Step 6 Check the Pure DNS Routing check box if you want to use only the DNS server specified in the incoming packets for DNS requests. This causes the DNS caching name service to determine the original destination IP address.

Step 7 Check the Ignore case of URLs during playback check box if you want to allow case-insensitive URL matches between the acquisition URL and the publishing URL.

Step 8 Click Submit to save the configuration.

To modify a website, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels. The Channels window appears.

Step 2 Click the Edit icon for the channel whose website you want to modify. The Modifying Channel window appears.

Step 3 Click the Edit Website button. The Modifying Web Site window appears.

Step 4 Enter changes to the website data as needed.

Step 5 Click Submit to save the changes.

Deleting Websites

Note When you delete a website, all channels that have been added for the website are also deleted.

To delete a website, follow these steps:

Step 1 To delete a website, go to the Modifying Channel window and click the Edit Website button. The Modifying Web Site window appears.

Step 2 Click the Trash icon. You are prompted to confirm your decision.

Step 3 Click OK to execute your request.

Configuring Channels for Channel Distribution

Channel distribution describes the manner in which content is distributed from the origin web server to all the Content Engines that are subscribed to the content, or more specifically, assigned to the channel that represents that group of content objects. (For an overview of the channel distribution architecture, see the "Content Acquisition and Distribution Architecture" section.)

Creating and Modifying Channels

Channels map the content from a website to the devices in your ACNS network. When you create a channel, you first create a directory of your content providers and then provide URLs to their websites. (See the "Creating and Modifying Content Providers" section and the "Creating and Modifying Websites" section.)

Using the Content Distribution Manager, you can create, modify, or remove channels from the ACNS network. Keep in mind that modifying channels can affect the availability of content on the ACNS network.

You create a channel by defining the following items:

•Name

•Content provider

•Website

•Channel quota

•Channel properties (channel priority, multicasting)

Creating a Channel

To create a channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels. The Channels window appears, listing all the channels in your ACNS network.

Step 2 Click the Create New Channel icon in the taskbar. The Creating New Channel window appears. (See Figure 5-6.)

Figure 5-6 Creating New Channel—Channel Properties

Step 3 Use the fields provided under the Channel Information heading to configure the channel name and website that the channel is associated with.

Step 4 Use the fields provided under the Acquisition and Distribution Properties heading to configure channel priority, enable multicasting, or disable encryption. (See Table 5-2 for a description of the channel properties fields. Required fields are indicated by an asterisk in the GUI and in Table 5-2.)

Table 5-2 Channel Properties

Property

Description

Channel information

Name*¹

Unique name for the channel.

Request Routed FQDN

Fully qualified domain name to route requests. Read only.

This field is configured from the Creating New Web Site window (see the "Creating and Modifying Websites" section) and is used if you have a Content Router in your network.

Origin Server

Fully qualified domain name of the origin server. Read only.

This field is configured from the Creating New Web Site window. (See the "Creating and Modifying Websites" section.)

Content Provider*

Name of the content provider associated with this channel. The default is None.

To add a new content provider to this drop-down list, see the "Creating and Modifying Content Providers" section.

WebSite*

Name of the website belonging to the content provider that is associated with this channel.

Note The website must be predefined in the Creating New Web Site window.

Live Channel

When checked, creates a live channel to distribute live or scheduled programs to the Content Engines associated with this channel. This channel does not have a related manifest file and cannot be used to distribute file-based content as regular channels do. The live channel learns about a live program through a program file that describes the attributes of the program.

Checking this check box disables the Channel Quota field and fields in the Acquisition and Distribution Properties section.

Channel Quota*

Maximum content storage size in megabytes for pre-positioning content for this channel.

See the "Channel Quota" section.

Acquisition and Distribution Properties

Distribution Priority*

Content distribution priority setting. Options are High, Normal, and Low. The default is Normal.

See the "Distribution Priority" section

Multicast only, Multicast/Unicast, or Unicast only*

Enables multicast-only, multicast transmission with failover to unicast, or unicast-only transmission.

See the "About IP Multicasting" section.

Use null cipher for Distribution

When checked, disables encryption for distribution.

¹* = required field. All other fields are optional.

Step 5 If you wish to add comments regarding the channel for the benefit of other Content Distribution Manager users, enter them in the Comments field provided.

Step 6 Click Submit to save the channel configuration.

Note To configure manifest file and manifest proxy information for a channel, see the "Configure Manifest File and Proxy Information for the Channel" section.

Modifying a Channel

To modify a channel, follow these steps:

Step 1 Choose Content > Channels to get to the Channels window.

Step 2 Click the Edit icon next to the name of the channel that you want to change. The Modifying Channel window appears. (See Figure 5-7.)

Figure 5-7 Modifying Channel Window

Step 3 Make changes to the channel configuration as needed.

To modify the Content Provider and WebSite fields, see the "Configuring Channel Elements" section.

Step 4 Click Submit to effect any changes you have made to the channel configuration. The Content Distribution Manager updates the channel information.

After you create a new channel, you need to designate a root Content Engine for the channel and then assign Content Engines or device groups to the channel. Although designating a root Content Engine and assigning devices to the channel can be done from the same GUI window, the following sections break out these steps into separate procedures.

Designating the Root Content Engine

The root Content Engine is the one Content Engine that is authorized to go directly to the origin web server for content. The root Content Engine then publishes the content to other Content Engines in the channel. You must designate a root Content Engine for content distribution to take place.

To designate one Content Engine to be the root Content Engine for a channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Edit icon next to the name of the channel to which you want to assign a root Content Engine. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 You can designate a root Content Engine when assigning device groups to the channel or when assigning Content Engines to the channel.

•In the Contents pane click Assign Content Engines. The Content Engine assignment to Channel window appears. Click the Assign button next to the name of the Content Engine, or click the Assign All Content Engines icon in the task bar and proceed to Step 4.

•Alternatively, click Assign device groups. The Device Group assignments for Channel window appears. Click the Assign button next to the name of the Content Engine, or click the Assign All Device Groups icon in the task bar and proceed to Step 4.

Step 4 Choose a Content Engine from the Root CE drop-down list. This list contains all of the Content Engines currently assigned to the channel in which you are working.

Note If there are no Content Engines or device groups assigned to the channel, no choices appear in the Root CE drop-down list. To add Content Engines to a channel, see the next two sections, "Adding and Removing Content Engines from Channels," and "Adding and Removing Device Groups from Channels."

Step 5 Click Submit.

Adding and Removing Content Engines from Channels

To add or remove Content Engines from a channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Edit icon next to the name of the channel that you want to change. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 In the Contents pane, choose Assign Content Engines. The Content Engine assignments for Channel window appears.

This window displays a list of the Content Engines in all locations to which they have been assigned, as well as the unreserved and total disk space in the cdnfs partition for each Content Engine. Content Engines can be added to the channel from more than one location.

Step 4 Click the Assign icon (blue cross mark) next to the name of the Content Engine that you wish to associate with the channel. Alternatively, you can click the Assign all Content Engines icon in the taskbar to perform a bulk addition of all Content Engines in various locations to the channel.

Step 5 Click Submit to add the Content Engines to the channel. Upon submission, a green tick mark appears next to the assigned Content Engine.

Step 6 To remove Content Engines, click the Unassign icon (green tick mark) next to the name of the Content Engine that you want to remove from the channel. Alternatively, you can click the Unassign all Content Engines icon in the taskbar to perform a bulk removal of all Content Engines from the selected channel.

Step 7 Click Submit to remove the Content Engines from the channel. The list of Content Engines in the channel shows a blue cross mark next to the name of the removed Content Engine.

If the Content Engine that you removed was the root Content Engine, and if there is at least one Content Engine still assigned to the channel, you must designate a new root Content Engine. (See the "Designating the Root Content Engine" section.)

Adding and Removing Device Groups from Channels

Device groups are assigned to channels through the Content Distribution Manager GUI. Whenever a channel is created and additional device groups are added, or a channel assignment to the device group changes, devices in the group are notified of their assignment to the associated channel.

The relationship between device groups and channels is many-to-many. A channel can have multiple device groups and device groups in turn can belong to multiple channels.

To add a device group from a channel, follow these steps.

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Edit icon next to the name of the channel to which you want to assign a device group or from which you want to remove a device group. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 In the Contents pane, choose Assign Device Groups. The Device Group assignments for Channel window appears, displaying the minimum unreserved disk space in the cdnfs partition. An asterisk (*) under the Note column denotes that there is no free space available to be assigned to this channel. A double asterisk (**) under the Note column denotes that Content Engines associated with this device group have been already assigned to this channel.

Step 4 Click the Assign icon (blue cross mark) next to the name of the device group that you wish to associate with the channel. A green tick mark appears next to the assigned device group after you click Submit. Alternatively, you can click the Assign all Device Groups icon in the taskbar to perform a bulk addition of all device groups in various locations to the channel.

Step 5 Click Submit to add the device groups to the channel.

To remove a device group from a channel, follow these steps.

Note When a device group is removed from a channel, the Content Engines that were part of the device group are also removed from the channel. When a device is removed from a device group containing the original channel assignment, this device is also unassigned from channels. Similarly, when a channel is removed from a device group, the associated devices are also unassigned.

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Edit icon next to the name of the channel to which you want to assign a device group or from which you want to remove a device group. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 In the Contents pane, choose Assign Device Groups. The Device Group assignments for Channel window appears, displaying the minimum unreserved disk space in the cdnfs partition. An asterisk (*) under the Note column denotes that there is no free space available to be assigned to this channel. A double asterisk (**) under the Note column denotes that Content Engines associated with this device group have been already assigned to this channel.

Step 4 Click the Unassign icon (green tick mark) next to the name of the device group that you want to remove from the channel. Alternatively, you can click the Unassign all Device Groups icon in the taskbar to perform a bulk removal of all device groups from the selected channel.

Step 5 Click Submit to remove the device groups from the channel. The browser window refreshes, listing the updated channels with a blue cross mark next to the unassigned device groups.

Deleting Channels

To delete a channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Edit icon next to the name of the channel that you want to delete. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 Click the Trash icon. You are prompted to confirm your decision to delete the channel.

Step 4 Click OK to confirm your decision. The channel is removed from the ACNS network.

Viewing Channels

To view all channels across your ACNS network, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

The Channels window appears, listing all the channels in your ACNS network. (See Figure 5-8.)

Figure 5-8 Channels Window

The channel type and the website that is associated with each channel are displayed in the row for each channel.

Step 2 To sort the channels by type, website, status, or state, click the respective column heading.

Step 3 To print the channel display table, click the Printer icon.

Viewing All Content Engines Assigned to a Channel

In the Content Distribution Manager GUI, a distinction is made between devices that are assigned directly to a channel or devices that are assigned through a device group. The assignments are tracked separately. For tracking purposes, the View all Content Engines assigned to Channel window displays all Content Engines assigned to a channel, regardless of whether they are assigned directly or through device groups.

To view the list of all Content Engines assigned to a channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels.

Step 2 Click the Edit icon next to the name of the channel that you want to view. The Modifying Channel window appears.

Step 3 In the Contents pane, choose List all assigned Content Engines. The View all Content Engines assigned to Channel window appears and lists all Content Engines assigned to the specified channel. (See Figure 5-9.)

Figure 5-9 View All Content Engines Assigned to Channel Window

Table 5-3 describes the information that is displayed in this window.

.

Table 5-3 Content Engine Channel Assignment Information

Column Heading

Description

Content Engine

Name of the Content Engine assigned to the channel.

Directly Assigned

Indicates whether the Content Engine was assigned directly to the channel (Yes or No).

Assigned through device group

Indicates whether the Content Engine was assigned through a device group. If yes, then this column displays the name of the device group. If no, then this column displays the value Not Applicable (N/A).

Distributing Content Through Unicast Replication

Once content is acquired from the origin server by the root Content Engine of a channel, it can be replicated through the channel either by unicast or multicast transmission. The basic channel distribution architecture provides for unicast content replication using a hop-by-hop store-and-forward methodology with the forwarder Content Engines systematically selected on the basis of the manually configured location hierarchy.

To distribute content through unicast, the ACNS network automatically creates a unidirectional distribution tree for each channel. The root node of the tree is the root Content Engine of the channel, and each Content Engine subscribed to the channel is a node on the tree.

For each node, its parent node is also called its forwarder Content Engine. The algorithm for automatically designating the forwarder Content Engine is called the channel routing algorithm.

Three general rules in the current channel routing algorithm are as follows:

1. In each location for each channel, only one Content Engine fetches content from another location for that channel. We call this Content Engine the location leader of the channel. All other Content Engines in this location use the location leader as the forwarder for this channel. There can be only one location leader per channel per location. Note that within one location, different channels may have different location leaders.

The location leader is computed automatically by the channel routing algorithm. ACNS 5.2 software allows you to influence which Content Engines are chosen as location leaders by setting a priority level for individual Content Engines in the location. Content Engines are all set to the lowest priority by default. The Content Engine with the highest priority is more likely to be chosen as the location leader. (See the next section, "Configuring Location Leader Preference and Forwarder Selection Probability".)

Use the show distribution channel EXEC command to see which Content Engine is the current forwarder for a channel. In ACNS 5.2 software a new field (reason/status) has been added to the command output to show why a Content Engine is unable find a forwarder. Use the show distribution forwarder-list EXEC command to see the forwarder selection order of a Content Engine for a channel.

2. The location leader finds a subscribed Content Engine from the closest location on the path toward the root Content Engine as its forwarder. If all the potential forwarders in a parent location are down (or unreachable) the location leader skips to the next location level in the hierarchy (towards the root Content Engine location) to find a forwarder.

ACNS 5.2 software allows you to set the number of levels that a location leader can search to find a forwarder. (See the "Configuring the Forwarder Lookup Level" section.)

You can also influence the selection of a forwarder by configuring the Content Engine with a distribution weight, by setting it to be used only as a last resort, or by taking it out of the forwarder list completely. The Content Engine configured with the heaviest weight has the highest probability of becoming the forwarder. (See the next section, "Configuring Location Leader Preference and Forwarder Selection Probability".)

3. If the location leader Content Engine fails for some time, another Content Engine in the location takes over as the location leader. If the root Content Engine fails, another Content Engine in the location takes over as the temporary root Content Engine.

When multicast transmission is desirable, channels and Content Engines can be enabled for multicasting.

See also, the "Configuring Weighted Load Balancing for Live Stream Splitting" section.

Configuring Location Leader Preference and Forwarder Selection Probability

To configure the location leader preference and forwarder probability settings, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Devices.

Step 2 Click the Edit icon next to the name of the Content Engine that you want to configure.

Step 3 In the Contents pane, choose Prepositioning > Location Leader and Forwarder. The Location Leader and Forwarder Settings for Content Engine window appears.

Step 4 To configure the location leader settings, click and slide the control button on the scale to the priority level (1-20) that you want. The lower the number, the lower the priority. The Content Engine with the highest priority is most likely to be chosen as the location leader.

Step 5 To configure the forwarder settings, choose an option (Weighted, Last Resort, Never Use) by clicking one of the Forwarder Probability radio buttons.

If you choose Weighted, click and slide the control button on the scale to the weight (1-20) that you want. The Content Engine with the greatest weight is most likely to be chosen as the forwarder.

Step 6 Click Submit to save the settings.

Configuring the Forwarder Lookup Level

To configure the forwarder lookup level, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Devices.

Step 2 Click the Edit icon next to the name of the Content Engine that you want to configure.

Step 3 In the Contents pane, choose Prepositioning > Distribution. The Distribution Settings for Content Engine window appears. (See Figure 5-10.)

Figure 5-10 Distribution Settings

Step 4 Click one of the Forwarder Lookup radio button options; chose Unlimited or chose Maximum and enter a number to limit how many location levels the location leader can search to find a forwarder.

Step 5 Click Submit to save the settings.

Configuring the Content Metadata Poll Interval Multiplier

Sender and receiver Content Engines exchange information before they transmit the actual content. This information is called metadata. Included in the metadata is the wait time between content updates (or the metadata polling interval), which the sender Content Engine sends to the receiver. The sender calculates this wait time based on a number of factors, such as the number of devices in the ACNS network or the number of receivers in the forwarder's queue. You can lengthen or shorten the wait time by configuring the content metadata poll interval multiplier on receiver Content Engines. This multiplier enables you to control how often receiver Content Engines notice changes in content. The polling interval that is calculated by the sender Content Engine will be either shorter or longer by a factor of the content metadata poll interval multiplier that you configure.

When the receiver Content Engine obtains the wait time from the sender, it multiplies the wait time by the value you specify in the multiplier. You can scale the unicast receiver Content Engine's next metadata poll interval down to 10 percent of normal or up to 10 times normal. For example, if you set the multiplier to 10% of normal, and the wait time between update polls is 120 seconds, the effective polling interval is shortened to 12 seconds (10% of normal or 0.1 x 120 is 12 seconds).

The higher the multiplier, the longer it takes for the receiver to be notified of changes in content and the less the network traffic that results from polling. On the other hand, the lower the multiplier, the less time it takes for the receiver to be notified of content changes, and the greater the network traffic that results from polling.

Note The content metadata poll interval multiplier applies only to a unicast receiver Content Engine, which regularly polls for new content metadata from its forwarder.

To configure the content metadata poll interval, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Devices.

Step 2 Click the Edit icon next to the name of the Content Engine that you want to configure.

Step 3 In the Contents pane, choose Prepositioning > Distribution. The Distribution Settings for Content Engine window appears. (See Figure 5-10.)

Step 4 Under the Distribution Settings heading, slide the Content Metadata Poll Interval Multiplier control either down or up to scale the unicast receiver Content Engine's next metadata poll interval.

Step 5 Click Submit to save the settings.

Commands Related to Distribution Settings

Table 5-4 lists and describes CLI commands that are related to distribution settings. For complete descriptions of these commands, including usage guidelines and examples, refer to the Cisco ACNS Software Command Reference, Release 5.2 publication.

Table 5-4 Distribution-Related Commands

Command

Syntax

Description

show distribution

show distribution location-leader-preference channel-id channel-id

Shows the configured location-leader-priority of the Content Engines that are subscribed to the channel.

show distribution forwarder-load-weight channel-id channel-id

Shows the configured forwarder-load-weight of the Content Engines that are subscribed to the channel.

show distribution channel

Shows which Content Engine is the current forwarder for a channel.

show distribution forwarder-list

Shows the forwarder selection order of a Content Engine for a channel.

Distributing Content Through Multicast Replication

Multicasting allows efficient distribution of content to multiple Content Engines and is useful when many end users are interested in the same content. ACNS software supports Pragmatic General Multicast (PGM)-based multicast replication using either satellite or multicast-enabled terrestrial infrastructures.

To prepare for multicast transmission of content, you should perform these tasks in the order presented in this section:

1. Enabling Content Engines for Multicasting

2. Configuring Multicast Cloud Properties

3. Assigning Content Engines to a Multicast Cloud

4. Assigning and Removing Multicast Clouds from Channels

About IP Multicasting

Multicast delivery enables the distribution of streaming media by allowing different receiving devices on the IP multicast to receive a single stream of media content from the Content Engine simultaneously. This can save significant network bandwidth consumption, because a single stream is sent to many devices, rather than sending a single stream to a single device every time that this stream is requested.

This multicast delivery feature is enabled by setting up a multicast address on the Content Engine to which different devices, configured to receive content from the same channel, can subscribe. The delivering device sends content to the multicast address set up at the Content Engine, from which it becomes available to all subscribed receiving devices.

To take advantage of multicasting, all devices, including Content Engines and routers, as well as clients, must be multicast-enabled. For this reason, multicasting is mostly used in local networks where routers can be configured for multicasting. Multicast delivery over the Internet can only be accomplished when all the devices that participate in the multicast have been enabled for multicasting.

About Multicast Clouds

For multicast content replication, Content Engines are grouped into multicast clouds. A multicast cloud consists of one sender Content Engine, an optional backup sender Content Engine, and at least one receiver Content Engine in a hub and spoke topology. All the Content Engines in one multicast cloud share a unique advertisement address that allows them to communicate multicast session information. The multicast cloud is then associated with one or more multicast-enabled channels.

In pull-based unicast content distribution, a unicast receiver pulls file data out of the proper forwarder (or root Content Engine) when a client requests the content. By contrast, in multicast content distribution, the sender Content Engine in a multicast cloud proactively pushes content into the cloud according to a preconfigured schedule.

The receiver Content Engines listen on the advertisement IP address for information on content to be replicated from the sender and decide whether to accept an advertisement and hence whether to receive the content.

Content metadata (machine-readable information that describes the characteristics of the content) must be distributed to a receiver first before the content itself can be replicated. Content metadata helps to define what content to retrieve, how content will be retrieved, how recently content has been updated, how content is to be pre-positioned (for example, expiration time), and so forth. Metadata is always distributed using unicast. Content, however, can be replicated using either multicast or unicast. A multicast receiver rejects the multicast sender's advertisement of a file if the proper content metadata has not yet arrived.

The Content Distribution Manager GUI allows you to configure multicast cloud parameters in the Creating New Multicast Cloud window. These parameters are discussed in the following sections.

Figure 5-11 shows the task flow for configuring a multicast cloud.

Figure 5-11 Multicast Cloud Configuration Task Flow

About Configuring Carousel Passes

The carousel pass setting defines the maximum number of times that the sender Content Engine can retransmit the multicast for missing files. The primary sender sends the first carousel pass automatically. After the first round, multicast receiver Content Engines request missing content by sending a negative acknowledgment (NACK) to the sender that identifies the missing content. The multicast sender sends out the requested content when it receives the NACK from the receiver. After all the receiver Content Engines have received all the multicast content or the sender has reached the maximum number of carousel passes, which ever comes first, the sender stops transmitting content.

If the primary sender fails and the backup sender becomes active, the backup sender takes charge of NACK processing. The backup sender's carousel passes are always triggered by a NACK. When the maximum number of carousel passes is reached for a file on the current active sender, you can configure file distribution to fall back to unicast, if this is desired. (See the "About Configuring Channel Options for Content Replication" section for more information.)

To adjust the pacing of the multicast transmission, you can specify how much time must elapse before missing files are resent (the Delay between passes field) in the Content Distribution Manager GUI Modifying Multicast Cloud window (Devices > Multicast Clouds > Modifying Multicast Cloud).

About the NACK Interval Multiplier

To identify missing content and trigger a resend of a file, receiver Content Engines send a negative acknowledgement (NACK) message to the sender Content Engine. NACK messages generated by many receiver Content Engines could generate more traffic than the sender can handle. ACNS 5.1 software allows you to adjust the average interval between NACKs by configuring a NACK interval multiplier for an individual receiver Content Engine. This value (an integer between 0.1 and 10) adjusts the default average NACK interval (the default is 20 minutes) by the value configured as the interval multiplier. For example, if you set the NACK interval multiplier to 3, the interval between NACKs becomes 20 minutes x 3, or 60 minutes.

This adjustment can be made as needed by choosing Devices > Devices > Prepositioning > Distribution in the Content Distribution Manager GUI.

To send an immediate NACK request rather than wait for the scheduled interval, you can issue the distribution multicast send-nack-now EXEC command on a multicast receiver Content Engine.

To configure the NACK interval multiplier, follow these steps:

Step 1 In the Content Distribution Manager GUI, choose Devices > Devices.

Step 2 Click the Edit icon next to the name of the Content Engine that you want to configure.

Step 3 In the Contents pane, choose Prepositioning > Distribution. The Distribution Settings for Content Engine window appears. (See Figure 5-10.)

Step 4 Click and drag the Content NACK Interval Multiplier slider control across the calibrated ruler to adjust the interval between NACK messages. The scale ranges from 10 percent of normal to 10 times normal. The center of the scale corresponding to "normal" denotes the default value of 20 minutes. The value corresponding to the position of the slider is displayed in the field next to it.

Step 5 Click Submit to save your settings.

About the File Resend or Stop Feature

To trigger resending of a particular file, or the content in a particular channel or all channels, you can issue the distribution multicast resend EXEC CLI command on a multicast sender. This command internally resets the number of carousel passes completed to zero for the desired target. Because the first resend of content always happens automatically without being triggered by a NACK, setting the carousel pass count to zero triggers a resend of the content. However, if the on-demand-only option is additionally specified, the first carousel pass made after the command has been issued can only be triggered by a NACK for the content involved.

To stop sending a particular file, a particular channel, or all channels, you can issue the distribution multicast stop EXEC command on a multicast sender. This command internally increases the number of carousels completed to the maximum integer. This prevents further carousel passes from being triggered.

About Configuring Multicast Forward Error Correction

Forward error correction (FEC) is a type of data encoding that protects transmissions against errors, without requiring retransmission. The FEC number denotes the number of packets that will be encoded into one FEC transmission group. The higher the FEC number, the bigger the transmission group size, and hence the more error-resistant the multicast may be, but also the more computational overhead there will be on the multicast sender and receivers. Note that there is no bandwidth overhead related to FEC.

In ACNS 5.0.1 software, the FEC default value is 8, whereas in ACNS 5.0.3 software and later, the FEC default is 16. If the multicast sender device is a high-end Content Engine model such as a CE-7325, you can set this number higher in order to improve multicast reliability, especially when your network connectivity has a high uniform loss rate. However, we do not recommend that you set this number beyond 64, because it may place too much of a load on all the receiver Content Engines.

Separately, you can also set proactive FEC using the PGM configuration file (a text file accessible from the Content Engine CLI in the /local1/multicast-expert-config/ directory [see the "Configuring PGM and File Transmission Parameters Using Multicast Expert Mode" section]). Proactive FEC is the number of extra packets that the multicast sender proactively sends out for every FEC number of data packets. The proactive FEC default value is 0. You can set it higher for better multicast reliability, for example, 2 proactive packets for every 16 FEC packets, at the expense of 12.5 percent traffic overhead (2 divided by 16).

Proactive FEC is an additional reliability measure above and beyond that of normal FEC. Although normal FEC does not incur bandwidth overhead, proactive FEC does. Proactive FEC primarily protects the multicast from uniform losses. For example, if the network has a uniform loss rate of 15 percent, then a proactive FEC of 2 extra packets for every 16 FEC packets (a 12.5 percent bandwidth overhead) cuts the effective loss rate down to 2.5 percent. Most network losses are not completely uniform. Still, during bursts, proactive FEC similarly undercuts the effective burst loss rate. For example, if the burst loss rate is 20 percent while the average loss rate is 2 percent, with proactive FEC at 12.5 percent, the receiver Content Engines experience a burst loss rate of 7.5 percent and an average loss rate near 0 percent.

About Configuring the Multicast Sender Delay Interval

The multicast sender delay interval is the amount of time before each multicast transmission begins. A period of delay before the actual multicast transmission begins is required to allow content metadata time to propagate to the receiver Content Engine. Metadata contains the content file and configuration information that is necessary for the successful transmission of content files. The default sender delay interval is 16 minutes. The sender delay parameter is used to configure an extra delay before a multicast transmission can begin.

When configuring the sender delay interval, you must take into account that the content metadata must first be propagated to the receiver before the multicast transmission can commence. During a multicast session, a receiver Content Engine sends out periodic requests for files that it has not yet received. The sender retransmits files only as requested by the receiver Content Engine. A multicast receiver will reject a multicast sender's advertisement of a file if the associated content metadata has not arrived yet. The sender delay option allows you to configure enough time for the metadata to propagate to the receiver, and thus avoid having the receiver reject the multicast sender's advertisement of a file.

To configure the sender delay interval, use the multicast sender-delay global configuration command on a sender Content Engine. You can configure the duration of the delay based on your expectation or best guess of the amount of time required for metadata to be propagated. The system takes this user-configured sender delay value and delays the multicast transmission by such a period.

Note The sender delay interval cannot be configured using the Content Distribution Manager GUI. You must configure the sender delay interval using the CLI of the sender Content Engine.

Configuring PGM and File Transmission Parameters Using Multicast Expert Mode

PGM is a reliable multicast protocol defined in IETF RFC 3208. It is designed for applications that require ordered or unordered, duplicate-free, multicast data delivery from multiple sources to multiple receivers. Support for reliable multicasting and file transmission is provided by the TIBCOSmartPGM FX tool set, which is integrated with Cisco ACNS 5.2 software. You can configure some PGM and file transmission (FX) parameters through the Content Distribution Manager GUI, such as the advertisement IP address, multicast-out bandwidth, TTL, FEC transmission group, and so forth.

In some cases, expert users might want to change other PGM and FX parameters to make the multicast file transfer more robust and efficient for their multicast environment. ACNS software allows you to change the configuration parameters of the TIBCOSmartPGM FX configuration file manually by using multicast expert mode on the Content Engine.

Caution We do not recommend that you change the TIBCOSmartPGM FX configuration file unless you are an expert in PGM multicasting and know how to adjust the configuration parameters.

ACNS software contains default TIBCOSmartPGM FX configuration files for multicast sender and receiver Content Engines. The multicast sender and receiver Content Engines determine the medium being used for the multicast by checking the configuration of the multicast cloud, and they then read the configuration parameter values from the PGM configuration file that corresponds to the medium (terrestrial or satellite) being used for the multicast.

ACNS 5.2 software uses the following default TIBCOSmartPGM FX configuration files:

•fxd.conf.src

•fxd.conf.rcv

In ACNS 5.1 and ACNS 5.0 software, default PGM and FX multicast configuration parameters are saved in two sets of files: FX parameters are saved in one set, and PGM parameters are saved in another. The default filenames are as follows:

•fxd.conf.src

•fxd.conf.rcv

•pgmfx.conf.src

•pgmfx.conf.rcv

Note Configuration file formats are not compatible across ACNS 5.2 software and ACNS 5.1 or 5.0 software. When you upgrade from ACNS 5.1 or 5.0 software to ACNS 5.2 software, your customized ACNS 5.1 and 5.0 configuration files in the /local1/multicast-expert-config/ directory are renamed with "_3" appended. When you downgrade from ACNS 5.2 software to ACNS 5.1 or 5.0 software, the ACNS 5.2 configuration files are renamed with "_4" appended. You must manually re-create your customized configuration files after upgrading or downgrading from ACNS 5.2 software.

The Content Engine stores sample copies of the default TIBCOSmartPGM FX configuration files in the /local1/multicast-expert-config/ directory for reference. You can modify one of these sample configuration files, rename it, and save it back to the multicast sender or receiver Content Engine. When you create customized configuration files and copy them to the /local1/multicast-expert-config/ directory using the default configuration filenames, the Content Engine uses the customized configuration file instead of the default configuration file. The customized configuration file becomes effective after the Content Engine is restarted.

Content Engines running ACNS 5.2 software contain the following sample configuration files:

•fxdSatellite.conf.src.sample—Use for a sender Content Engine in a satellite network

•fxdSatellite.conf.rcv.sample—Use for a receiver Content Engine in a satellite network

•fxdTerra.conf.src.sample—Use for a sender Content Engine in a terrestrial network

•fxdTerra.conf.rcv.sample—Use for a receiver Content Engine in a terrestrial network

Content Engines running ACNS 5.1 and ACNS 5.0 software contain the following sample configuration files:

•pgmfxSatellite.conf.src.sample

•pgmfxSatellite.conf.rcv.sample

•pgmfxTerra.conf.src.sample

•pgmfxTerra.conf.rcv.sample

To change the configuration parameters of a default TIBCOSmartPGM FX configuration file, follow these steps:

Step 1 Log in to the multicast sender Content Engine using FTP.

a. From a PC running Windows, choose Start > Run.

b. In the Open field, enter ftp ipaddress, using the IP address of the multicast sender or receiver Content Engine.

c. At the User prompt, enter your administrator-level username.

d. At the password prompt, enter your password. The FTP prompt (ftp>) appears.

Step 2 At the FTP prompt, open the multicast-expert-config directory.
ftp> cd multicast-expert-config
250 CWD command is successful.
ftp>
Step 3 List the sample configuration files in the directory.
ftp> ls
200 PORT command successful.
150 Opening ASCII mode data connection for file list.
fxdSatellite.conf.rcv.sample
fxdSatellite.conf.src.sample
fxdTerra.conf.rcv.sample
fxdTerra.conf.src.sample
226 Transfer complete.
ftp: 297 bytes received in 0.01Seconds 29.70Kbytes/sec.
Determine which sample file you want to retrieve, based on whether you are configuring the multicast sender or the receiver and whether your network is using terrestrial or satellite media transmission.

Step 4 Return to binary mode from ASCII mode.
ftp> bin
200 Type set to I.
Step 5 Copy the configuration file to your desktop.
ftp> get fxdSatellite.conf.rcv.sample 
200 PORT command successful.
Opening BINARY mode data connection for fxdSatellite.conf.rcv.sample (5607 bytes).
226 Transfer complete.
ftp: 5607 bytes received in 0.00Seconds 5607000.00Kbytes/sec.
ftp>
Step 6 End the FTP session.
ftp> quit
Step 7 Locate the configuration file on your PC and open it using any text editor.

Step 8 Edit the sample configuration file by making any needed changes.

Step 9 Save the file using Save As, and give it the same name as the default configuration file that you want to replace. For example, save the file named fxdSatellite.conf.rcv.sample as fxd.conf.rcv.

Step 10 Transfer the file back to the multicast sender or receiver Content Engine multicast-expert-config directory.

a. Log in to the Content Engine using FTP.

b. Open the multicast-expert-config directory.

c. Enter binary mode.

d. Transfer the file into the directory. For example:
C:\>ftp 128.19.220.79
Connected to 128.19.220.79.
220 CONTENTENGING FTP server (Version wu-2.7.0(2) Tue Sep 7 17:20:20 P
DT 2004) ready.
User (128.19.220.79:(none)):admin
331 Password required for admin.
Password:
230 User admin logged in.  Access restrictions apply.
ftp> cd multicast-expert-config
250 CWD command successful.
ftp> bin
200 Type set to I.
ftp> put fxd.conf.rcv
200 PORT command successful.
150 Opening BINARY mode data connection for fxd.conf.src.
226 Transfer complete.
ftp:5607 bytes sent in 0.01Seconds 560.70Kbytes/sec.
ftp> quit
Step 11 Restart the multicast sender or receiver Content Engine for the new configuration to take effect.

About Configuring Channel Options for Content Replication

Once a multicast cloud is configured, it must be associated with one or more multicast-enabled channels for multicast replication of content to take place within the channel. The channel configuration offers various transmission options for replicating content; a channel can be configured for multicast and unicast (multicast with failover to unicast), multicast-only, or unicast-only transmission.

Multicast and Unicast

When a channel is configured for multicast and unicast, the receiver Content Engine uses unicast to download content only after all carousel passes have been exhausted and after the preconfigured multicast transmission fails. In a multicast cloud configuration that uses a backup sender, when the channel is enabled for multicast and unicast, the failover to unicast occurs when the current active multicast sender has exhausted all the carousel passes for the file.

If the administrator wants the Content Engines to fall back to unicast (for example, with a multitier unicast deployment using a terrestrial multicast medium), the multicast cloud should be configured for a low number of carousel passes (such as 1, 2, or 3).

Multicast Only

However, if only multicast replication is desired (for example, with a hub and spoke or star topology deployment using a satellite multicast medium), the channels should be configured as multicast-only, with a high number of carousel passes configured in the multicast cloud (such as 10 or more).

When a channel is configured to be multicast only (that is, when the channels are associated with a multicast cloud and the subscribing receiver Content Engine has multicast service successfully licensed and enabled), content replication takes place only through multicasting. No retransmission takes place in unicast at all. This prevents background unicast polls from happening and taking up bandwidth. However, if a Content Engine in the multicast-only channel is not licensed and enabled for multicasting, it can continue to request all the content from a multicast-only channel through unicasting.

Enabling Content Engines for Multicasting

Before you can create a multicast cloud, you must have a multicast distribution license key (purchased from Cisco Systems) and Content Engines that are enabled for multicasting. These multicast-enabled Content Engines can then be assigned as sender and receiver Content Engines when you configure the multicast cloud.

Content Engines for multicasting must be assigned to the multicast cloud, which in turn is assigned to multicast-enabled channels. Also, you need to assign individual Content Engine senders and receivers of the cloud to the particular multicast-enabled channel. You must do this additional step even though the multicast cloud is associated with the channel.

Note You must assign the multicast cloud to a channel first, then assign the individual Content Engines to the channel.

To enable Content Engines for multicasting, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Devices.

Step 2 Click the Edit icon next to the name of the Content Engine that you want to enable for multicasting. The Content Engine Device Home window appears.

Step 3 In the Contents pane, choose Prepositioning > Multicast Distribution License. The Multicast Distribution License Agreement window appears.

The Multicast Distribution Agreement for Content Engine window appears only if you have not read and accepted the multicast distribution license for the device. To accept the license, follow these steps:

a. Read the terms of this agreement.

b. Check the Accept License check box.

c. Click Submit.

The window refreshes and the Multicast Distribution License Settings for Content Engine window appears.

Step 4 Check the Enable check box, and enter the license key in the License Key field.

Alternatively, check the Evaluate check box to enable an evaluation license key for a set period.

Step 5 Click Submit.

Step 6 Return to the Modifying Content Engine window and repeat Step 1 through Step 5 to enable multicasting on other Content Engines in your ACNS network.

Step 7 To modify or delete the multicast distribution license settings, you have the following options:

•To delete the configured settings for the device, click the Remove Device Settings icon in the taskbar.

•To apply the factory default settings for the device, click the Apply Defaults icon in the taskbar.

•To override the device group settings that have been applied from device groups to which the device is associated, click the Override Group Settings icon in the taskbar.

When a device is associated with one or many device groups that have been configured with the settings displayed in this window, you can choose the device group name from the drop-down list whose settings you want to apply to the device.

Step 8 Proceed to the next section, "Configuring Multicast Cloud Properties," to create a multicast cloud.

Configuring Multicast Cloud Properties

A multicast cloud is configured by specifying an IP multicast address for advertising the data being transferred, an IP multicast address range for transferring the data, a primary multicast sender Content Engine and an optional backup sender, a set of receiver Content Engines, and a maximum rate at which to send the data.

Note We highly recommend that you avoid using multicast addresses of the form x.0.0.y (for example, 238.0.0.1). These addresses hash to the same Ethernet address space as 224.0.0.x, which is used frequently by routers and switches for local multicasts. Additional traffic on these addresses adds to the workload of these network elements.

To configure a multicast cloud, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Multicast Clouds. The Multicast Clouds window appears.

Step 2 Click the Create New Multicast Cloud icon in the taskbar. The Creating New Multicast Cloud window appears. (See Figure 5-12.) See Table 5-5 for a description of multicast cloud parameters.

Figure 5-12 Creating New Multicast Cloud Window

Step 3 Configure the basic multicast cloud information:

a. Enter a name for the multicast cloud in the Name field.

b. Enter an advertisement address in the Advertisement IP address field.

When creating the multicast cloud, you must assign a unique advertisement address. This provides all the Content Engines in one cloud with the same advertisement address and allows them to communicate multicast session information.

c. Enter a port number in the Port field. This is the port used by file transfer addresses. The default port is 7777.

Step 4 Configure the multicast address settings:

a. Enter a start IP address and an end IP address in the fields provided.

Once the multicast cloud is configured and you associate the multicast cloud with one or more multicast-enabled channels, this multicast address range is used to provide each channel associated with it a unique data channel multicast address. When you assign a channel to the multicast cloud, an unused IP address is automatically selected from this range to ensure that the address is used by only one channel and by only one multicast cloud.

b. Enter a maximum multicast rate in kilobits per second (kbps) in the Default Multicast-out Bandwidth field. This value applies to the sender Content Engine.

Tip The multicast-out bandwidth should be a realistic value, no greater than 102400 kbps (100 mbps). If your network has both Gigabit Ethernet and Fast Ethernet connections and you have low-end Content Engine models in the multicast cloud, set the default multicast-out bandwidth no higher than 10240 kbps (10 mbps). If all of the Content Engines in your network are high-end models (CE-732x) and your network contains all Gigabit Ethernet connections, you can set the default multicast-out bandwidth as high as 102400 kbps (100 mbps). If you set the value higher than this, the receiver might fail to receive the entire file.

c. If you have a backup sender configured, enter a maximum multicast rate in kilobits per second (kbps) in the Backup CE Default Multicast-out Bandwidth field.

Step 5 Configure the multicast cloud advanced settings as necessary:

a. Based on your means of transmitting the multicast, choose either Satellite or Terrestrial from the Multicast medium drop-down list.

b. Enter the number of hops for Time To Live in the TTL field.

The TTL field dictates how many hops a packet travels before it is discarded, regardless of whether or not the packet has reached its destination.

c. Enter the number of carousel passes in the # of Carousel passes field.

This is the maximum number of times that a multicast sender can send the content of the channel to which it is assigned. The multicast sender can be set to fall back to unicast after the maximum number of carousel passes has been reached.

If you want the Content Engines to fall back to unicast (for example, with a multitier unicast deployment using a terrestrial multicast medium), the multicast cloud should be configured for a low number of carousel passes (such as 1, 2, or 3).

However, if multicast replication is preferred (for example, with a hub and spoke or star topology deployment using a satellite multicast medium), use a high number of carousel passes, such as 10 or more.

Note If a channel is set to multicast only and the receiver is multicast-ready, the maximum number of configurable carousel passes is 1,000,000,000. If the number of carousel passes configured is used up, the syslog displays a warning message as an alert.

d. Choose a value for the FEC transmission group from the drop-down list.

FEC data encoding protects transmissions against errors, without requiring retransmission. The FEC number denotes the number of packets that will be encoded into one FEC transmission group. The higher the number, the bigger the transmission group size, and hence, the more error-resistant the multicast may be, but also the more computational overhead there will be on the multicast sender and receivers. Note that there is no bandwidth overhead related to FEC.

e. Enter a value, in minutes, for the Delay between passes field. This sets the interval between file transmissions.

f. To enable the IP router alert option for Pragmatic Group Multicasting (PGM) packets, check the PGM Router-assist check box.

This option specifies whether IP routers are to be used to assist in distribution of content.

g. Enter a value, in minutes, for the Primary-to-backup failover grace period. The range is 5 to 7200 minutes. The default is 30 minutes.

This is the amount of time allotted for the backup sender to detect whether the primary sender is active.

h. Enter a value, in minutes, for the Backup-to-primary fallback grace period. The range is 5 to 7200 minutes. The default is 30 minutes.

This is the amount of time allotted for the primary sender to detect whether the backup is active.

Step 6 If you wish, enter any comments in the Comments field.

Step 7 Click Submit to save the configuration.

Your multicast cloud configuration is saved, and you can proceed to Step 3 in the "Assigning Content Engines to a Multicast Cloud" section.

Note If you have not assigned any receiver Content Engines, a message appears, stating that your transaction is not complete until you assign receiver Content Engines to the multicast cloud.

Table 5-5 describes the parameters that you need to define in the Content Distribution Manager GUI when configuring a multicast cloud. Required fields are marked with an asterisk in the GUI and in the table.

Table 5-5 Multicast Cloud Parameters

Field

Description

Multicast Cloud Information

Name*¹

Identifier for the multicast cloud. The name must be unique across the system.

Advertisement IP address*

Multicast address collectively known and used by a multicast cloud to implement a communication channel.

The advertisement IP address must conform to these guidelines:

•It must be unique across the system.

•Each multicast cloud must have one advertisement address.

•It cannot be used in another multicast cloud.

•It must be within the RFC multicast range (224.0.0.0-239.255.255.255).

•It must not be within the start and end range specified by this cloud.

•It must not be any user-specified multicast address for programs.

•It must not be within the program multicast pool start and end range (as defined in System > Program Addresses).

See "IP Multicast Addressing," for information on multicast address restrictions.

Port*

Port used for file addresses. The default port is 7777.

Multicast Address Settings

Start IP address*

Start of the IP address range, which must be within the range 224.0.0.0 to 239.255.255.255.

The IP address range must conform to the following:

•The IP address range cannot overlap with program multicast pool addresses.

•The IP address range must contain all multicast addresses used by this cloud with its associated channel.

Note The IP address range in one multicast cloud can overlap that of another multicast cloud. A message alerts you that there is an overlap, but allows the operation. See "IP Multicast Addressing," for information on multicast address restrictions.

End IP address*

End of the IP address range, which must be higher than the start IP address. The end IP address must be within the range 224.0.0.0 to 239.255.255.255.

See "IP Multicast Addressing," for information on multicast address restrictions.

Default Multicast-out Bandwidth*

Maximum multicast rate in kilobits per second (kbps). The minimum rate is 10 kbps.

This is the default multicast-out bandwidth, which is applied 24 hours a day, 7 days a week. The multicast-out bandwidth is associated with the sender Content Engine only.

To customize bandwidth rates for different days, use the A&D Bandwidth Settings window. These settings override the default for the period that you specify. (See the "Configuring Acquisition and Distribution Bandwidth Settings for Scheduled Times" section.)

Synchronize Primary and Backup CE Multicast-out Bandwidth

When checked, default multicast-out bandwidth settings are used by both primary and backup senders, if a backup sender is configured.

Backup CE Default Multicast-out Bandwidth

Maximum multicast rate in kilobits per second (kbps) for the backup sender. The minimum rate is 10 kbps.

Advanced Settings

Multicast medium

Means of transmitting the multicast, either satellite or terrestrial. The default is satellite.

TTL

Time To Live expressed as the number of hops (1-255). The default is 255.

FEC transmission group

Size of an FEC (forward error correction) block in packets. (Refer to RFC 3208 PGM Reliable Transport Protocol Specification for more information.) The allowable inputs are 2, 4, 8, 16, 32, 64, and 128. The default is 16.

# of Carousel passes

Maximum number of times (1-1000000000) that a multicast sender will attempt to send missing content for on-demand carousels. The default is 5.

Note If the multicast sender finishes the last carousel on an object at time t and the multicast sender receives a NACK within t + carousel_delay, the multicast sender starts the next carousel of this object at time t + carousel_delay. That is, the multicast carousel is not triggered immediately upon receipt of the NACK if the carousel delay is greater than zero (0).

Delay between passes

Delay between file transmissions, in minutes (0-10080) (7 days * 24 hours * 60 minutes). The default is 0 minutes.

PGM Router-assist

Specifies whether IP routers are to be used to assist in distribution of content. Checking this check box enables the IP router alert option for PGM packets.

Note PGM packet routing is supported in Cisco IOS 12.0(5)T and later 12.0 T releases.

Primary-to-backup failover grace period

Amount of time allotted for the backup sender to detect whether the primary sender is active. If the backup sender does not hear a heartbeat from the primary sender within this grace period, the backup sender assumes the active role.

The range is 5-7200 minutes. The default is 30 minutes.

Backup-to-primary fallback grace period

Amount of time allotted for the primary sender to detect whether the backup is active. If the backup sender does not respond within this grace period, the primary sender assumes the active role.

The range is 5-7200 minutes. The default is 30 minutes.

Comments

Comments about the multicast cloud.

¹* = required field. All other fields are optional.

Modifying a Multicast Cloud

To modify a multicast cloud, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Network > Multicast Clouds. The Multicast Clouds window appears.

Step 2 Click the Edit icon next to the name of the multicast cloud that you want to change. The Modifying Multicast Cloud window appears.

Step 3 Edit the information or settings as needed.

Step 4 Click Submit to save the changes.

Deleting Multicast Clouds

To delete a multicast cloud, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Network > Multicast Clouds. The Multicast Clouds window appears.

Step 2 Click the Edit icon next to the name of the multicast cloud that you want to delete. The Modifying Multicast Cloud window appears.

Step 3 Click the Trash icon in the taskbar. You are prompted to confirm your action.

Step 4 Click OK. The multicast cloud is deleted.

Viewing Multicast Clouds

To view a list of all the multicast clouds configured in your network, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Network > Multicast Clouds. The Multicast Clouds window appears, listing all the multicast clouds in your ACNS network.

The table also displays the sender Content Engine for each multicast cloud.

Step 2 To print the table data, click the Printer icon.

Assigning Content Engines to a Multicast Cloud

Note Content Engines must be multicast-enabled with the multicast distribution license before you can add them to a multicast cloud. (See the "Enabling Content Engines for Multicasting" section.)

To add Content Engines to a multicast cloud, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Multicast Clouds. The Multicast Clouds window appears.

Step 2 Click the Edit icon next to the name of the multicast cloud to which you want to add receiver Content Engines. The Modifying Multicast Cloud window appears.

Step 3 In the Contents pane, click Assign Content Engines. The CE assignments for Multicast Cloud window appears.

Step 4 Assign multicast receiver, sender, and backup sender Content Engines. Table 5-6 describes the Content Engine role assignments for a multicast cloud.

a. Choose Receiver from the Role drop-down list and click the Assign icon (blue cross mark) next to the name of the Content Engine that you want to assign to the receiver role. Click Submit. Repeat this step if you wish to assign multiple receiver Content Engines to the multicast cloud.

Alternatively, click the Assign all Content Engines icon in the taskbar to perform a bulk addition of all Content Engines in various locations to the multicast cloud and click Submit.

b. Choose Primary Sender from the Role drop-down list and click the Assign icon next to the name of the Content Engine that you want to assign to the primary sender role and click Submit.

c. If you wish, choose Backup Sender from the Role drop-down list and click the Assign icon next to the name of the Content Engine that you want to assign to the backup sender role and click Submit.

Note The Content Distribution Manager GUI allows you to assign Content Engines that are not multicast enabled. However, you must ensure that any Content Engine that you assign to a multicast cloud is multicast enabled with a multicast license. (See the "Enabling Content Engines for Multicasting" section.)

Table 5-6 Content Engine Role Assignments for Multicast Clouds

Role Assignment

Description

Receiver

Content Engines that receive content from the primary sender. To create a functional multicast cloud, you must add at least one receiver Content Engine.

Use the following guidelines when adding receiver Content Engines:

•You must choose at least one Content Engine to be a receiver.

•The maximum number of receivers you can add is the total number of Content Engines in the system (excluding the sender Content Engine).

•The receiver cannot be a receiver in another multicast cloud.

•The receiver cannot be a sender in the same multicast cloud. Only Content Engines that are not assigned to another multicast cloud are displayed as selections in the Content Distribution Manager GUI.

•Only a fully configured multicast cloud (with at least one receiver Content Engine) can be associated with a channel to enable multicast capability.

•The list of Content Engines for selection is sorted by location. You can choose individual Content Engines from one or more locations to add to this multicast cloud.

Note Only Content Engines that are not assigned as receiver Content Engines to another multicast cloud or as sender Content Engines to this cloud are displayed as selections in the Content Distribution Manager GUI.

Primary sender

Primary Content Engine forwarder that pushes content to a set of Content Engine receivers using multicast.

Primary senders must conform to the following rules:

•The primary sender cannot be the backup sender for the same cloud.

•The primary sender cannot be the receiver for the same cloud.

•The primary sender cannot be the primary sender for a different cloud.

•The primary sender cannot be the backup sender for a different cloud.

A sender Content Engine cannot be deleted from the network. Before deleting a sender Content Engine, you must choose another Content Engine as the sender for the multicast cloud.

Backup sender

Content Engine configured for backup in the event of failure of the primary sender Content Engine.

Backup senders must conform to the following rules:

•The backup sender cannot be the primary sender for the same cloud.

•The backup sender cannot be the receiver for the same cloud.

•The backup sender cannot be the primary sender for a different cloud.

•The backup sender cannot be the backup sender for a different cloud.

The primary and backup senders of a multicast cloud should subscribe to the same set of multicast-enabled channels.

To remove a Content Engine from the multicast cloud, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Devices > Multicast Clouds. The Multicast Clouds window appears.

Step 2 Click the Edit icon next to the name of the multicast cloud from which you want to remove receiver Content Engines. The Modifying Multicast Cloud window appears.

Step 3 In the Contents pane, click Assign Content Engines. The CE assignments for Multicast Cloud window appears.

Step 4 Click the Unassign icon next to the name of the Content Engine that you want to remove. Alternatively, you can click the Unassign all Content Engines icon in the taskbar to perform a bulk removal of all Content Engines in various locations from the multicast cloud.

Step 5 Click Submit to remove the Content Engines from the multicast cloud. After you click Submit, a blue cross mark appears next to the unassigned Content Engine.

Assigning and Removing Multicast Clouds from Channels

You can assign or remove multicast clouds only from channels that are multicast-enabled. A channel is multicast-enabled when you click the Multicast/Unicast radio button or the Multicast-only radio button when you create or modify the channel. (To create a new channel, see the "Creating and Modifying Channels" section.)

Note When a multicast cloud is assigned to a channel, the Content Engines that are part of the multicast cloud must also be individually assigned to the channel for multicasting. To assign Content Engines to a channel, follow the procedure in the "Adding and Removing Content Engines from Channels" section.

To assign a multicast cloud from a multicast-enabled channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels. The Channels window appears (see Figure 5-8), listing all the channels in your ACNS network.

Step 2 Click the Edit icon next to the name of the channel to which you want to assign a multicast cloud a multicast cloud. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 Enable multicasting on the channel, if you have not already done so.

a. Click the Multicast only or Multicast/Unicast radio button.

b. Click Submit.

Step 4 In the Contents pane, choose Assign Multicast Cloud. The Assigning Multicast Clouds to Channel window appears. (See Figure 5-13.)

Figure 5-13 Assigning Multicast Clouds to Channel Window

Step 5 Click the Assign Multicast Cloud to Channel icon in the taskbar. The Assign Multicast Cloud to Channel Assignment window appears.

Step 6 Choose a multicast cloud from the drop-down list. The window refreshes, showing the IP address range for that multicast cloud. In the IP address to use for this Channel field, enter any available IP address from this range to assign to this channel. (The first available address automatically populates this field; however, you can change the address.)

In Figure 5-14 a multicast cloud has already been chosen and the window has refreshed, showing the IP address range for the cloud.

Figure 5-14 Assign Multicast Cloud to Channel Assignment Window

Step 7 Click Submit.

To remove a multicast cloud from a channel, follow these steps:

Step 1 From the Content Distribution Manager GUI, choose Content > Channels. The Channels window appears (see Figure 5-8), listing all the channels in your ACNS network.

Step 2 Click the Edit icon next to the name of the channel from which you want to remove a multicast cloud. The Modifying Channel window appears. (See Figure 5-7.)

Step 3 Click the Edit icon next to the name of the multicast cloud that you want to remove. The Assign Multicast Cloud to Channel Assignment window appears.

Step 4 Click the Trash icon. You are prompted to confirm the action.

Step 5 Click OK. The channel is removed.

Verifying the Multicast Configuration

Use the following checklist to verify your multicast configuration:

1. Verify that all Content Engines being added to the multicast cloud are online and enabled for multicasting by using the show multicast EXEC command.

2. After multicast connectivity has been confirmed, configure the multicast cloud parameters: sender, advertisement address, transfer address, range, multicast-out bandwidth, multicast medium (satellite or terrestrial), number of carousel passes, and receiver Content Engines.

3. Verify the properties of the multicast cloud by using the show distribution mcast-data-sender EXEC command for the sender Content Engine and show distribution mcast-data-receiver EXEC command for receiver Content Engines.

4. Configure a channel for multicasting and assign a multicast cloud to it.

5. Assign multicast senders and the desired receiver Content Engines from the assigned multicast cloud to the channel.

6. After a multicast channel has been configured on the Content Distribution Manager, use the show statistics distribution mcast-sender EXEC command and the show statistics distribution mcast-receiver EXEC command to show the progress of a data transfer.

Commands Related to Multicasting

Table 5-7 lists and describes CLI commands that are related to multicasting. For complete descriptions of these commands, including usage guidelines and examples, refer to the Cisco ACNS Software Command Reference, Release 5.2 publication.

Table 5-7 Multicast-Related Commands

Command

Syntax

Description

distribution multicast

distribution multicast send-nack-now

Generates a NACK for missing objects and sends them to the multicast receiver.

distribution multicast resend

Resends an individual object (object option) or specifies that the first round of carousel passes be triggered by a NACK only (on-demand-only option).

distribution multicast stop

Sets the number of carousel passes completed to the maximum value so that no more multicast carousels can be triggered.

multicast

multicast {accept-license-agreement | enable | evaluate | license-key key | sender-delay delay}

Controls enabling and disabling of multicasting, including reading and accepting the license and entering the key.

Note We recommend that you use the Content Distribution Manager GUI rather than the CLI to configure multicasting.

multicast connectivity-test

Verifies multicast connectivity between a sender and one or more receivers.

multicast fixed-carousel enable

Enables fixed carousel sending, regardless of receiver feedback; NACK triggered carousel passes are disabled. Only applies to the primary sender and is disabled if the Content Engine becomes a backup sender.

multicast priority-weight

Sets the percentage of multicast bandwidth for priority-based scheduling. The remaining bandwidth is given to time-based scheduling of queued jobs.

The default is 50%.

multicast back-version-compatibility

Makes the multicast sender backward compatible with the receivers of the specified software version.

show multicast

show multicast [license-agreement]

Displays the current status of the multicast client. If the license-agreement option is included in the command string, the full text of the multicast license agreement is displayed.

show distribution

show distribution mcast-data-receiver

show distribution mcast-data-sender

show distribution location

Shows information about the multicast receiver or the sender. Displays information about the multicast cloud.

show statistics distribution

show statistics distribution mcast-data-receiver

show statistics distribution mcast-data-sender

Displays the content distribution statistics of the multicast data receiver or sender.

clear statistics distribution

clear statistics distribution mcast-data-receiver

clear statistics distribution mcast-data-sender

Clears multicast statistics.

Multicast Sender Interoperability Issues

A multicast sender Content Engine running ACNS 5.2 software can successfully send content to multicast receiver Content Engines running ACNS 5.0 or 5.1 software; however, a multicast receiver Content Engine running ACNS 5.2 software cannot interact with sender Content Engines that are running a lower version of ACNS software. We recommend that you upgrade your multicast sender to ACNS 5.2 software first and then upgrade your receivers to ACNS 5.2 software.

ACNS software releases prior to ACNS 5.1.x do not support some of the multicast cloud features introduced in ACNS 5.1.x software and supported in ACNS 5.2.x software. If you are running mixed versions of ACNS software in your network, you should consider the following additional information regarding multicast sender interoperability.

•Condition 1: The ACNS network is set up for multicast distribution with Content Engines subscribed to multicast-enabled channels. Multicast sender and receiver Content Engines are running mixed versions of ACNS software. All Content Engines have been successfully enabled for multicasting. The Content Distribution Manager is running ACNS 5.1.x or a later release of ACNS 5.x software.

Symptom:

–Only senders running ACNS 5.1.x or a later release of ACNS 5.x software support failover to a backup sender. Only receivers running ACNS 5.1.x or a later release of ACNS 5.x software can send negative acknowledgements (NACKs).

–If both the primary sender and the backup sender are actively sending the same file, the receiver Content Engine locks out one of the two and receives one copy of the file from the first sender.

Note Cases 1 through 6 assume that you are using a Content Distribution Manager that is running ACNS 5.1.x or a later release of ACNS 5.x software.

Case 1: The primary sender is using an ACNS software release earlier than ACNS 5.1.x. The backup sender is using ACNS 5.1.x or a later release of ACNS 5.x software, as is the receiver.

–The backup sender considers the primary sender inactive and becomes active after the configured failover period.

–The primary sender periodically sends multicast files as configured in the carousel pass and multicast-out bandwidth settings.

–The receiver tries to send a NACK to the primary sender, but receives NACK failures and begins sending NACKs to the backup sender. The backup sender responds to the NACK.

Case 2: Both the primary sender and the backup sender are using ACNS 5.1.x or a later release of ACNS 5.x software. The receiver is using an ACNS software release earlier than ACNS 5.1.x.

–Failover works between the primary and backup senders, but neither the primary sender nor the backup sender ever receives a NACK response from the receiver.

–The primary sender sends out the first carousel pass for content without the need for a NACK, so the receiver might be able to obtain content if it joins the group promptly. If it does not, the receiver is not able to obtain content.

Case 3: Both the primary sender and the receiver are using an ACNS software release earlier than ACNS 5.1.x. The backup sender is using ACNS 5.1.x or a later release of ACNS 5.x software.

–The backup sender considers the primary sender inactive and becomes active after the configured failover grace period. The backup sender continues to wait for a NACK response from the receiver before sending the multicast, but the receiver is unable to send a NACK.

–The primary sender periodically sends multicast files as configured in the carousel pass and multicast-out bandwidth settings.

–The receiver should be able to obtain content from the primary sender.

•Condition 2: Although you may have received a warning message from the Content Distribution Manager, you can still configure a Content Engine as a backup sender if the Content Engine is registered with a Content Distribution Manager running ACNS 5.1.x or a later release of ACNS 5.x software and the Content Engine is running ACNS software earlier than ACNS 5.1.x. Cases 4 through 6 discuss the backup sender operating under these conditions.

Symptom: The Content Distribution Manager does not send related configuration information and configuration changes to the Content Engine running the earlier software version. This results in the the Content Engine not being able to identify itself as the multicast backup sender. This scenario might also occur if a backup sender using ACNS 5.1.x or a later release of ACNS 5.x software is downgraded to an earlier software version through the Content Engine CLI.

Case 4: Both the primary sender and the backup sender are using an ACNS software release earlier than ACNS 5.1.x. The receiver is running ACNS 5.1.x or a later release of ACNS 5.x software.

–The receiver alternates attempts to send NACKs between the primary sender and the backup sender but is unsuccessful.

–The primary sender periodically sends multicast files as configured in the carousel and multicast-out bandwidth settings.

Case 5: The primary sender and the receiver are using ACNS 5.1.x or a later release of ACNS 5.x software. The backup sender is using an ACNS software release earlier than ACNS 5.1.x.

–The primary sender considers the backup sender inactive after the configured failover grace period.

–The receiver can successfully send NACKs only to the primary sender. If the primary sender fails, the receiver sends the NACKs to the backup sender, and when it receives a NACK failure as expected, the receiver retries the primary sender. The receiver alternates sending NACKs between the senders until the primary sender becomes active again.

Case 6: The primary sender is using ACNS 5.1.x or a later release of ACNS 5.x software. Both the backup sender and the receiver are using an ACNS software release earlier than ACNS 5.1.x.

–The primary sender considers the backup sender inactive and becomes active after the configured failover grace period. The primary sender sends the first carousel pass of content without needing to receive a NACK. The primary sender then waits for the receiver's NACK to trigger further carousel passes if more than one carousel pass is configured.

–The receiver never sends a NACK to the primary sender or the backup sender.

•Condition 3: The Content Distribution Manager is using an ACNS software release earlier than ACNS 5.1.x. In software releases earlier than ACNS 5.1.x, only one sender is configurable for each multicast cloud.

Case 7: The sender is using ACNS 5.1.x or a later release of ACNS 5.x software. The receiver is using a software release earlier than ACNS 5.1.x.

The sender behaves like a primary sender running ACNS 5.1.x software. That is, it sends the first round of content without requiring a NACK to trigger the carousel pass. However, the sender is unable to continue making carousel passes because the receiver is unable to send NACKs.

Case 8: Both the sender and the receiver are using ACNS 5.1.x or a later release of ACNS 5.x software.

The sender is able to perform carousel passes and the receiver is able to send NACKs for missing content; however, there is no support for a backup sender or for configuring the NACK interval multiplier.

Case 9: The sender is using an ACNS software release earlier than ACNS 5.1.x. The receiver is using ACNS 5.1.x or a later release of ACNS 5.x software.

–The sender periodically sends multicast files as configured in the carousel pass and multicast-out bandwidth settings so that the receiver can obtain content.

–The receiver tries to send NACKs to the sender but continually fails and retries.

Workaround for Cases 1 through 9: Upgrade both senders and receivers to ACNS 5.1.x or a later release of ACNS 5.x software. Upgrade the sender first, and then upgrade the receivers.

Workarounds for Case 7 only:

–Use the distribution multicast resend EXEC command on the sender Content Engine to trigger a multicast carousel pass manually.

–Upgrade both senders and receivers to ACNS 5.1.x or a later release of ACNS 5.x software. Upgrade the sender first, and then upgrade the receivers.

Where to Go Next

In this chapter you have accomplished the following tasks:

•Configured your distribution topology by creating and modifying locations

•Defined websites, providing URLs for the origin web servers that store the website content

•Created channels to map content from the origin server to the Content Engines in your ACNS network

•Enabled channels for unicast or multicast transmission, or both

•Assigned Content Engines to channels

•Created multicast clouds for multicasting

Now you are ready to configure additional device settings for acquiring pre-positioned content and to define the content that you want to acquire. Proceed to the next chapter, "Configuring the ACNS Network for Content Acquisition."