Table of Contents

Preparing to Configure CDN Devices

Preparing to Configure CDN Devices

Before you configure CDN devices on your network, you must prepare for the configuration. This chapter tells you what you must do before you begin the configuration process and what information you need during the configuration process.

This chapter contains the following sections:

• What to Do Before Configuration
  
  
• Configuring DNS
  
  
• Determining Whether Your Network Uses a DHCP Server
  
  
• Setting Up the Oracle 8i DBMS
  
  
• About Configuring CDN Devices
  
  

What to Do Before Configuration

When you set up a Content Delivery Network, you work with three types of devices: a Content Distribution Manager, Content Routers, and Content Engines. Optionally, a fourth and fifth device type can be added: Content Services Switches for the creation of supernodes, and Cisco Catalyst 4000 or 5000 Family switches.

Before you begin configuring CDN devices, you must do the following:

• Configure DNS.
  
  

DNS must be configured before you use your CDN to deliver content, or the CDN will not deliver the content. Configuring DNS correctly is critical, so do it first. For information, see the "Configuring DNS" section.

• Determine whether your network uses a Dynamic Host Configuration Protocol (DHCP) server.
  

If your network does not use a DHCP server or if it uses a DHCP server that does not assign static IP addresses, you must provide network information when you configure the Content Distribution Manager, Content Routers, and Content Engines. For information, see the "Determining Whether Your Network Uses a DHCP Server" section.

• Set up the Oracle 8i database.
  
  

The Content Distribution Manager uses an external Oracle 8i database to store current CDN policies, so you must set up the database. For information, see the "Setting Up the Oracle 8i DBMS" section.

• Obtain the information you need for configuring your CDN devices.
  
  

During the configuration process, you need to enter information about your network to respond to prompts from the setup script. For information, see the "Gathering Device Configuration Information" section.

Configuring DNS

When end users click CDN URLs to request content, Cisco Internet CDN Software uses DNS to route the requests, using Content Routers, to the Content Engines hosting the content requested. Content Routers and Content Engines run DNS servers that know how to answer requests related to the CDN. Before your CDN can serve content associated with a domain, you must have DNS configured properly. It is important that you understand the following definitions before you proceed with configuring DNS.

• Hosted domain—A hosted domain name always has a minimum of four components. An example of a hosted domain is www.cdn.example.com.
  
• Delegated domain—A delegated domain is the name that is delegated from some other DNS server to the CDN. It comprises the last three parts of a hosted domain. An example of a delegated domain is cdn.example.com. It is possible to have multiple domains delegated to the CDN, and to create many hosted domains per delegated domain.
  

Configuring DNS involves defining the delegated domain on your DNS server and creating mappings in the configuration file (also known as a "zone file") of a domain to the Content Routers that will handle requests for that domain.

Note   You should create CDN parent domains on your DNS server before you create the hosted domain on the Content Distribution Manager user interface.

For instructions on creating hosted domains through the Content Distribution Manage user interface, refer to Chapter 2 of the Cisco Internet CDN Software User Guide.

Parent domains must be configured using conventional DNS tools.

To configure a delegated domain, list the Content Router host names as name servers for the domain. Cisco Internet CDN Software allows you to configure a maximum of eight Content Routers.

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Note   Be careful to create only as many name servers as you have Content Routers at hand—even if you plan on adding Content Routers to your CDN later. Reserving IP addresses for Content Routers that you are not assigning to actual devices will adversely affect content routing on your CDN.

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To create your delegated domains, apply one of the following three naming conventions to the domain names:

• If you want the hosted domain to appear as a subdomain of the customer, a delegated domain (cdn, in the following example) must be created within each customer domain. A sample DNS zone file fragment follows:
  

$ORIGIN example.com

...

cdn 

IN NS 1d hostname_of_content_router_1.example.com.

IN NS 1d hostname_of_content_router_2.example.com.

IN NS 1d hostname_of_content_router_3.example.com.

where:

example.com is the company for which you are serving content.

cdn is the subdomain you created within www.example.com.

hostname_of_content_router_x is the host name of the Content Router to which you want to map this domain.

1d is one day, the TTL (Time To Live) value of the NS (Name Server) record. You can specify the TTL value in days (d), hours (h), minutes (m), or seconds (s).

With the preceding DNS configuration, the following hosted domain is mapped to the Content Routers that you specified:

www.cdn.example.com 

• If you want the hosted domain to appear as a subdomain of the Internet service provider's domain, a single delegated domain (content, in the following example) can be shared by all content providers as follows:
  

$ORIGIN ISP.net

...

content 

IN NS hostname_of_content_router_1.ISP.net.

IN NS hostname_of_content_router_2.ISP.net.

IN NS hostname_of_content_router_3.ISP.net.

 

where:

ISP.net is you, the service provider.

content is the subdomain you created within www.ISP.net.

hostname_of_content_router_x is the host name of the Content Router to which you want to map this domain.

Using the preceding DNS configuration, you could create the following hosted domains mapped to the Content Routers that you specified:

www.customer1.content.ISP.net 
www.customer2.content.ISP.net

• If you want to assign an alias to the hosted domain, for example, to advertise a name with only three components, you must enter the alias name in the Edit Hosted Domain page of the Content Distribution Manager. You must also enter the following in the configuration file of the hosted domain:
  
  

$ORIGIN example.com

...

www IN CNAME 1d www.cdn.

 

or

www IN CNAME 1d example.content.ISP.net.

Determining Whether Your Network Uses a DHCP Server

We recommend that you determine whether your network uses a DHCP server, and what kind of a DHCP server it is.

• If your network uses a DHCP server, the DHCP server automatically provides your CDN devices with network configuration information.
  

Caution   Do not use your DHCP server if it cannot assign static IP addresses, because every MAC address on your network must have a single, fixed IP address and fully qualified domain name associated with it.

• If your network does not use a DHCP server or if it uses a DHCP server that does not assign static IP addresses, you must provide network configuration information (the IP address, netmask, and gateway address) when you configure your CDN devices.
  

For the network information you must provide, see the "Gathering Device Configuration Information" section.

Setting Up the Oracle 8i DBMS

You must have an Oracle 8i database in use at your organization that can be used as the Cisco Internet CDN policy database. The Oracle server does not need to be dedicated to the Cisco Internet CDN. Use the instructions below to properly install the Oracle database, if you have not already done so, and to reserve resources on the Oracle database that will be used by the Cisco Internet CDN.

Installing the Oracle DBMS

You must install the Oracle 8i database management system (DBMS) on your host network. To do so, follow the instructions included with the Oracle DBMS.

During the installation, note the port number that the Oracle listener is configured to use. You need this port number when you configure the Content Distribution Manager.

Note   The default listener port number is 1521.

You also need the database administrator account username and password.

Note   The default database administrator account username is system, and the default password is manager.

Use the Oracle tools to create a database and note the session name you assign when you create the database.

Configuring the Oracle Database

From a Windows, Linux, or UNIX client, log in as the database administrator to the Oracle session and host previously created using a database administration tool such as SQL*Plus.

Note   You may need to enter the connection information in the tnsnames.ora file found under the Oracle/networks/admin directory on your client system.

Perform the following SQL commands.

Note   The following SQL commands are provided as an example. Refer to an SQL command reference for more information.

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Note   Change the data file path to match the physical drives on the host Oracle server. SQL*Plus allows you to enter a single command as multiple lines.

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SQL> create tablespace cdn DATAFILE `datafile path on Oracle Server' 
SIZE 250M REUSE default storage(initial 25K next 10K minextents 1 
maxextents unlimited pctincrease 50);

 
SQL> create tablespace cdntemp DATAFILE 
`datafile path on Oracle Server' SIZE 250M REUSE default 
storage(initial 25K next 10K minextents 1 maxextents unlimited 
pctincrease 50);

 

Additional data files can be associated with the tablespace using the following command.

SQL> alter tablespace cdn add DATAFILE 
`datafile path on Oracle Server' SIZE 250M REUSE default 
storage(initial 25K next 20K minextents 1 maxextents unlimited 
pctincrease 50);

 

Step 2   List the names of the rollback segments:

SQL> select segment_name from dba_rollback_segs;

 

Rollback segments are used to keep information about the current transaction so that if an error occurs, the database can be returned to the state it was in before the transaction began.

Step 3   For the rollback segment listed in Step 2, change the max extents to be unlimited.

SQL> alter rollback segment rollback_segment_name STORAGE (NEXT 2 M 
MAXEXTENTS unlimited);

 

You may also want to create a database user for Cisco Internet CDN Software at this time.

Step 4   Use the following command to create a Cisco Internet CDN Software user account and password along with default tablespaces.

SQL> create user username identified by password default tablespace 
cdn temporary tablespace cdntemp;

 

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Note   When prompted to enter a database username during the dbsetup component of the device setup routine, do not enter the database username you created here. Instead, enter the default Oracle administrator username and password. See Cha pter 3, "Configuring CDN Devices," for information on using dbsetup to configure CDN devices.

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Step 5   Grant access rights to the new user.

SQL> grant CREATE SESSION, connect, resource to username;

 

You can use dbsetup to create your database schema (see the "Configuring the Content Distribution Manager" section), but you can also install the Cisco Internet CDN Software database schema by using an SQL script shipped with Cisco Internet CDN Software. This script contains the table definitions for Cisco Internet CDN Software and can be modified to change things such as tablespace declarations, but the actual table column definition should remain unchanged.

Step 6   To load and run the script, you must first reconnect to the database using SQL*Plus and log in as the database user for Cisco Internet CDN Software. Then use the start command to run the following MerlotCreate.sql script:

SQL> start LOCALPATH\MerlotCreate.sql

 

About Configuring CDN Devices

With the exception of the Content Services Switch, CDN devices must be configured using the setup program. Setup is a comprehensive configuration program that encompasses three other configuration routines:

• netsetup—This routine captures network configuration for the device such as the primary and content IP addresses, subnet, gateway, and DHCP information.
  
• dbsetup—This routine validates the Oracle 8i database that stores CDN data.
  
• register—This routine connects Content Engines and Content Routers to their assigned Content Distribution Manager.
  

You run the setup program on each device to name the device, specify the Oracle database information and DNS server information for the Content Distribution Manager, specify network interfaces and network information, bring the network online, generate certificates, and register the Content Distribution Manager, Content Routers, and Content Engines.

Note   If you have not completed the preconfiguration tasks described in the "What to Do Before Configuration" section, do them before you start configuring your CDN devices. Otherwise, your CDN will not deliver content to users.

Configuration Priorities

When you begin your CDN device configuration, configure your devices according to the following priorities:

See the following sections for CDN device configuration information:

• "Configuration Information for Content Services Switches" section
  
  
• "Configuring the Content Services Switch" section
  
  
• "Configuration Information for Content Distribution Manager, Content Engines, and Content Routers" section
  
  
• "Configuring the Content Distribution Manager" section
  
  
• "Configuring a Content Router" section
  
  
• "Configuring a Content Engine" section
  
  

CDN Device Network Addressing

Your CDN devices use a number of different network addresses to manage different types of content requests from end users and from other devices on the CDN. This section identifies and explains the different kinds of addresses you are asked to supply during configuration of your CDN devices. Make sure that you understand the purpose of each type of network address before continuing with device configuration.

Primary Versus Content IP Address

Content Routers and Content Engines require two IP addresses to operate: a primary IP address and a content IP address. The Content Distribution Manager requires only a single address, the primary IP address.

• The primary IP address is used for inter-CDN communication and administration of the system: for example, passing configuration information from the Content Distribution Manager to the devices it manages.
  

The primary IP address does not change. If DHCP is used for the primary IP address, an administrator must make sure that the Content Router or Content Engine is always assigned the same IP address by the server.

• The content IP address is used by devices to respond to DNS queries originating from web browsers, media players, and DNS servers located outside the CDN. Content Routers accept DNS queries at their content IP address. Content Engines accept DNS queries, as well as HTTP and Real-Time Streaming Protocol (RTSP) requests at their content IP address. Content Distribution Managers do not have a content IP address.
  

You must assign each IP address to an Ethernet port. The primary and content IP addresses can each use a unique Ethernet port, or they can share a single port.

• The primary IP address should be assigned to the first Ethernet port interface, eth0.
  
• The content IP address can be assigned to either eth0 or a different port.
  

If you decide to use separate Ethernet ports for the primary and content IP addresses, you must provide separate subnet and gateway information for each port. In this case, DHCP is capable of assigning one IP address per interface.

See the "CDN Device Wiring Configuration" section for more information on assigning your primary and content IP addresses to the appropriate port on your CDN device.

Virtual Address

The Content Services Switch is configured with one or more virtual IP addresses. These addresses are assigned one per cluster for each cluster associated with the Content Services Switch.

When requests are received for a particular cluster using that cluster's virtual IP address, the Content Services Switch uses Network Address Translation (NAT) to map the virtual IP address to the content IP addresses of the Content Engines in that cluster.

Internal Subnet Addresses

The Content Services Switch maintains an internal subnet of Content Engine content IP addresses referred to as the internal subnet. It is from this list of addresses that the Content Services Switch chooses Content Engines to serve content.

CSS Configuration Address

The Content Services Switch maintains an address, the CSS configuration address, through which it communicates with the Content Distribution Manager. Requests and commands are sent from the Content Distribution Manager, programmatically, to the Content Services Switch at the CSS configuration address using Secure Shell (SSH) to encrypt this traffic.

Gathering Device Configuration Information

Before you configure your CDN devices, you need to have specific information available so you can respond to prompts during configuration.

Configuration Information for Content Distribution Manager, Content Engines, and Content Routers

Table 2-1 shows the device information you need when you configure the Content Distribution Manager, Content Routers, and Content Engines.

If your network uses a DHCP server, then you do not provide network configuration information when you configure CDN devices. If your network does not use a DHCP server, then you must provide network configuration information when you configure your CDN devices. Table 2-2 shows the network information you need for the Content Distribution Manager, Content Routers, and Content Engines.

The Content Distribution Manager uses an external Oracle 8i database to store current CDN policies. Table 2-3 shows the Oracle database server information you need during the Content Distribution Manager configuration.

After you have the database and network information, you are ready to configure your CDN devices.

Configuration Information for Content Services Switches

The Content Services Switch is an optional component of the Internet CDN Software. If you are not deploying a Content Services Switch on your CDN, continue with the next chapter.

Note   Before you can use the Content Services Switch with your other CDN devices, you must first obtain a valid Secure Shell (SSH) license and license key and then activate your SSH software. The SSH software license key is on a sticker attached to the cover of your Content Services Switch documentation.

Table 2-4 shows the device information you need when you configure the Content Services Switch, which is used to create supernodes.

Connecting to CDN Devices Using the Command-Line Interface

Although the Content Distribution Manager graphical user interface (GUI) can be used to modify many CDN device configuration settings once a device has been properly configured, initial device setup takes place using the CDN command-line interface (CLI). After initial setup, certain maintenance and troubleshooting activities—such as modifying a device network address or restarting a device that has been stopped—also require you to interact with CDN devices using the CLI.

You can access the CLI for a CDN device by connecting a console cable to the designated console cable port on the device and attaching the device to a console terminal or a PC running terminal emulation software such as Telnet or SSH. Refer to the Cisco hardware documentation that came with your CDN device for instructions on connecting the console cable.

Note   Before you can use the Content Services Switch with your other CDN devices, you must first obtain a valid SSH license and license key and then activate your SSH software. The SSH software license key is on a sticker attached to the cover of your Content Services Switch documentation.

Refer to the Cisco hardware documentation that came with your CDN device for detailed information on cabling and accessing the device's CLI or web-based management interface (where applicable). Also refer to the Cisco Internet CDN Software Command Reference for detailed instructions on using Cisco Internet CDN Software commands.