Cisco SCE8000 GBE Software Configuration Guide, Release 3.6.x - Global Configuration [Cisco Service Control Operating System Software]

Table Of Contents

Global Configuration

Introduction

IP Routing Configuration

Configuring the IP Routing Table

How to Configure the Default Gateway

How to Add an Entry to the IP Routing Table

How to Display the IP Routing Table

IP Advertising

Configuring IP Advertising

How to Display the Current IP Advertising Configuration

Configuring Time Clocks and Time Zone

Displaying the System Time

Displaying the System Time: Example

Displaying the Calendar Time

Displaying the Calendar Time: Example

Setting the System Clock

Options

Setting the System Clock: Example

Setting the Calendar

Options

Setting the Calendar: Example

Setting the Time Zone

Options

Setting the Time Zone: Example

Removing the Current Time Zone Setting

Configuring Daylight Saving Time

Options

Guidelines

How to Define Recurring Daylight Saving Time Transitions

How to Define Non-Recurring Daylight Saving Time Transitions

How to Cancel the Daylight Saving Time Configuration

How to Display the Current Daylight Saving Time Configuration

Configuring SNTP

How to Enable the SNTP Multicast Client

How to Disable the SNTP Multicast Client

How to Enable the SNTP Unicast Client

Options

Enabling SNTP Unicast Client: Example

Disabling the SNTP Unicast Client

How to Disable the SNTP Unicast Client and Remove All Servers

How to Remove One SNTP Server

How to Define the SNTP Unicast Update Interval

Options

How to Display SNTP Information

Domain Name Server (DNS) Settings

Configuring DNS Lookup

How to Enable DNS Lookup

How to Disable DNS Lookup

Configuring Name Servers

Options

How to Define Domain Name Servers

How to Remove a Domain Name Server

How to Remove All Domain Name Servers

How to Add a Host to the Host Table

Options

Adding Hosts to Removing them from the Host Table: Example

How to Display Current DNS Settings

Displaying Current DNS Settings: Example

Configuring Cisco Discovery Protocol

Cisco Discovery Protocol

Cisco Discovery Protocol on the Cisco SCE8000 Platform

CDP Operational Modes on the Cisco SCE8000

CDP Limitations on the Cisco SCE8000

Configuring CDP on the Cisco SCE8000 Platform

Enabling CDP Globally

Setting CDP Mode

Enabling CDP on a Specific Traffic Interface

Setting the Hold Time

Setting the Timer

Monitoring and Maintaining CDP

CDP Configuration Examples

Example: Setting the CDP Mode

Example: Monitoring and Maintaining CDP

Global Configuration

Revised: September 27, 2012, OL-21060-09

Introduction

This chapter explains how to perform global configuration tasks, including IP routing and clock and time zone settings.

•IP Routing Configuration

•Configuring Time Clocks and Time Zone

•Configuring SNTP

•Domain Name Server (DNS) Settings

•Configuring Cisco Discovery Protocol

IP Routing Configuration

•Configuring the IP Routing Table

•IP Advertising

Configuring the IP Routing Table

•How to Configure the Default Gateway

•How to Add an Entry to the IP Routing Table

•How to Display the IP Routing Table

For handling IP packets on the out-of-band MNG port, the SCE platform maintains a static routing table. When a packet is sent, the system checks the routing table for proper routing, and forwards the packet accordingly. In cases where the SCE platform cannot determine where to route a packet, it sends the packet to the default gateway.

SCE platform supports the configuration of the default gateway as the default next hop router, as well as the configuration of the routing table to provide different next hop routers for different subnets (for maximum configuration of 100 subnets).

The following sections illustrate how to use CLI commands to configure various parameters.

The following commands are relevant to IP routing tables:

•ip default-gateway

•ip route prefix mask next-hop

•no ip route all

•no ip route prefix mask

•show ip route

•show ip route prefix

•show ip route prefix mask

How to Configure the Default Gateway

Options

The following option is available:

•ip-address—the IP address of the default gateway.

Step 1 From the SCE(config)# prompt, type ip default-gateway ip-address, and press Enter.

Configuring the Default Gateway: Example

The following example shows how to set the default gateway IP of the SCE platform to 10.1.1.1.
SCE(config)#ip default-gateway 10.1.1.1
How to Add an Entry to the IP Routing Table

Options

The following options are available:

•prefix — IP address of the routing entry, in dotted notation.

•mask — The relevant subnet mask, in dotted notation

•next-hop — The IP address of the next hop in the route, in dotted notation.

Must be within the MNG interface subnet.

Step 1 From the SCE(config)# prompt, type ip route prefix mask next-hop, and press Enter.

Adds the specified IP routing entry to the routing table.

How to Add an Entry to the IP Routing Table: Example

The following example shows how to set the router 10.1.1.250 as the next hop to subnet 10.2.0.0.
SCE(config)#ip route 10.2.0.0 255.255.0.0 10.1.1.250
How to Display the IP Routing Table

•How to Display the Entire IP Routing Table

•How to Display the IP Routing Table for a Specified Subnet

How to Display the Entire IP Routing Table

Step 1 From the SCE# prompt, type show ip route and press Enter.

Displays the entire routing table and the destination of last resort (default-gateway)

Displaying the Entire IP Routing Table: Example

This example shows how to display the routing table.
SCE#show ip route 
gateway of last resort is        10.1.1.1 
|    prefix       |     mask         |    next hop     | 
|-----------------|------------------|-----------------| 
|        10.2.0.0 |     255.255.0.0  |      10.1.1.250 | 
|        10.3.0.0 |     255.255.0.0  |      10.1.1.253 | 
|        198.0.0.0 |       255.0.0.0 |      10.1.1.251 | 
|        10.1.60.0 |   255.255.255.0 |      10.1.1.5   |
How to Display the IP Routing Table for a Specified Subnet

Options

The following options are available:

•prefix — IP address of the routing entry, in dotted notation.

•mask — The relevant subnet mask, in dotted notation

Step 1 From the SCE# prompt, type show ip route prefix mask and press Enter.

Displays the routing table for the specified subnet (prefix/mask).

Displaying the IP Routing Table for a Specified Subnet: Example

This example shows how to display the routing table for a specified subnet.
SCE#show ip route 10.1.60.0 255.255.255.0 
|    prefix       |     mask        |    next hop     | 
|-----------------|-----------------|-----------------| 
|       10.1.60.0 |   255.255.255.0 |        10.1.1.5 | 
sce#
IP Advertising

•Configuring IP Advertising

•How to Display the Current IP Advertising Configuration

IP advertising is the act of periodically sending ping requests to a configured address at configured intervals. This maintains the SCE platform IP/MAC addresses in the memory of adaptive network elements, such as switches, even during a long period of inactivity.

The following commands are relevant to IP advertising:

•[no] ip advertising

•ip advertising destination

•ip advertising interval

•default ip advertising destination

•default ip advertising interval

•show ip advertising

•show ip advertising destination

•show ip advertising interval

Configuring IP Advertising

To configure IP advertising, you must first enable IP advertising. You may then specify a destination address to which the ping request is to be sent and/or the frequency of the ping requests (interval). If no destination or interval is explicitly configured, the default values are assumed.

Options

The following options are available in the IP advertising commands:

•interval — The time interval between pings in seconds.

default interval = 300 seconds

•destination — The IP address of the destination for the ping requests

default destination = 127.0.0.1

How to Enable IP Advertising

Step 1 From the SCE(config)# prompt, type ip advertising and press Enter.

Enables IP advertising.

How to Configure the IP Advertising Destination

Step 1 From the SCE(config)# prompt, type ip advertising destination destination, and press Enter.

Configures the destination for the IP advertising pings.

How to Configure the IP Advertising Interval

Step 1 From the SCE(config)# prompt, type ip advertising interval interval, and press Enter.

Configures the frequency of the IP advertising pings.

Configuring IP Advertising: Example

The following example shows how to configure IP advertising, specifying 10.1.1.1 as the destination and an interval of 240 seconds.
SCE(config)#ip advertising destination 10.1.1.1
SCE(config)#ip advertising interval 240
How to Display the Current IP Advertising Configuration

Step 1 From the SCE# prompt, type show ip advertising and press Enter.

Displays the status of IP advertising (enabled or disabled), the configured destination, and the configured interval

Configuring Time Clocks and Time Zone

•Displaying the System Time

•Displaying the Calendar Time

•Setting the System Clock

•Setting the Calendar

•Setting the Time Zone

•Removing the Current Time Zone Setting

•Configuring Daylight Saving Time

The SCE platform has three types of time settings, which can be configured: the clock, the calendar, and the time zone. It is important to synchronize the clock and calendar to the local time, and to set the time zone properly. The SCE platform does not track Daylight Saving Time automatically, so you must update the time zone when the time changes bi-annually.

The SCE platform has the following two time sources:

•A real-time clock, called the calendar, that continuously keeps track of the time, even when the SCE platform is not powered up. When the SCE platform reboots, the calendar time is used to set the system clock. The calendar is not used for time tracking during system operation.

•A system clock, which creates all the time stamps during normal operation. This clock clears if the system shuts down. During a system boot, the clock is initialized to show the time indicated by the calendar.

It does not matter which clock you set first, as long as you use the clock and calendar read commands to ensure they are synchronized.

The time zone settings are important because they allow the system to communicate properly with other systems in other time zones. The system is configured based on Coordinated Universal Time (UTC), which is standard in the industry for coordination with other manufacturers' hardware and software. For example, Pacific Standard Time would be written as PST-10, meaning that the name of the time zone is PST, which is 10 hours behind Universal Time.

When setting and showing the time, the time is always typed or displayed according to the local time zone configured.

Displaying the System Time

Step 1 From the SCE(config)# prompt, type show clock and press Enter.

Displaying the System Time: Example

The following example shows the current system clock.
SCE#show clock 
12:50:03  UTC  MON  November 13 2001 
sce#
Displaying the Calendar Time

Step 1 From the SCE(config)# prompt, type show calendar and press Enter.

Displaying the Calendar Time: Example

The following example shows the current system calendar.
SCE#show calendar 
12:50:03  UTC  MON  May 11 2007 
sce#
Setting the System Clock

Options

The following option is available:

•time-date the time and date you want to set, in the following format:

hh:mm:ss day month year

Step 1 From the SCE# prompt, type clock set time-date and press Enter.

Sets the system clock to the specified time and date.

Setting the System Clock: Example

The following example shows how to set the clock to 20 minutes past 10 AM, May 13, 2007, updates the calendar and then displays the time.
SCE#clock set 10:20:00 13 may 2007 
SCE#clock update-calendar 
SCE#show clock 
10:21:10  UTC  THU  May  13  2007
Setting the Calendar

The calendar is a system clock that continues functioning even when the system shuts down.

Options

The following option is available:

•time-date —the time and date you want to set, in the following format:

hh:mm:ss day month year

Step 1 From the SCE# prompt, type calendar set time-date and press Enter.

Sets the system calendar to the specified time and date.

The time specified in this command is relative to the configured time zone.

Step 2 From the SCE# prompt, type clock read-calendar and press Enter.

Synchronizes the system clock with the calendar time you just set .

Setting the Calendar: Example

The following example shows that the calendar is set to 10:20 AM, May 13, 2007. The clock is then synchronized with the calendar setting.
SCE#calendar set 10:20:00 13 may 20017 
SCE#clock read-calendar 
SCE#show calendar 
10:21:06  UTC  THU  May  13  2007
Setting the Time Zone

Options

The following options are available:

•zone — The name of the time zone to be displayed.

default = GMT

•hours — The hours offset from UTC. This must be an integer in the range -23 to 23.

default = 0

•minutes — The minutes offset from UTC. This must be an integer in the range of 0 to 59. Use this parameter to specify an additional offset in minutes when the offset is not measured in whole hours.

default = 0

Step 1 From the SCE(config)# prompt, type clock timezone zone hours minutes and press Enter.

Sets the timezone to the specified timezone name with the configured offset in hours and minutes.

Setting the Time Zone: Example

The following example shows how to set the time zone to Pacific Standard Time with an offset of 10 hours behind UTC.
SCE(config)#clock timezone PST -10 
SCE(config)#
Removing the Current Time Zone Setting

Step 1 From the SCE(config)# prompt, type no clock timezone and press Enter.

Removes the timezone configuration and resets the timezone to the default value (UTC).

Configuring Daylight Saving Time

The SCE platform can be configured to automatically switch to daylight saving time on a specified date, and also to switch back to standard time. In addition, the time zone code can be configured to vary with daylight saving time if required. (For instance, in the eastern United States, standard time is designated EST, and daylight saving time is designated EDT).

•Options

•Guidelines

•How to Define Recurring Daylight Saving Time Transitions

•How to Define Non-Recurring Daylight Saving Time Transitions

•How to Cancel the Daylight Saving Time Configuration

•How to Display the Current Daylight Saving Time Configuration

Options

The transition times into and out of daylight saving time may be configured in one of two ways, depending on how the dates for the beginning and end of daylight saving time are determined for the particular location:

•recurring — If daylight saving time always begins and ends on the same day every year, (as in the United States), the clock summer-time recurring command is used. The beginning and ending days for daylight saving time can be configured once, and the system will automatically perform the switch every year.

•not recurring — If the start and end of daylight saving time is different every year, (as in Israel), the clock summer-time command is used. In this case, the transitions must be configured every year for that particular year. (Note that "year" is not necessarily a calendar year. If the transition days are determined in the fall, the transitions for that fall and the next spring may be configured.)

The day on which the transition takes place may be defined in several ways:

•Specific date — For example, March 29, 2004. A specific date, including the year, is defined for a not recurring configuration.

•First/last occurrence of a day of the week in a specified month — For example, the last Sunday in March. This is used for a recurring configuration.

•Day of the week in a specific week in a specified month — For example, Sunday of the fourth week of March. (This would be different from the last Sunday of the month whenever there were five Sundays in the month). This is used for a recurring configuration.

The following options are available:

•zone — the time zone code for daylight saving time

•week (recurring only)— the week of the month on which daylight saving begins (week1) and ends (week2)

•day (recurring only) — the day of the week on which daylight savings begin (day1) and ends (day2)

•date (non-recurring only) — the date of the month on which daylight saving begins (date1) and ends (date2)

•month — the month in which daylight saving begins (month1) and ends (month2)

•year (non-recurring only) — the year in which daylight saving begins (year1) and ends (year2)

•offset — the difference in minutes between standard time and daylight saving time.

Default = 60 minutes

Guidelines

General guidelines for configuring daylight saving time transitions:

•Specify the time zone code for daylight saving time.

•recurring — specify a day of the month (week#|first|last/day of the week/month).

•not recurring — specify a date (month/day of the month/year).

•Define two days:

–Day1 = beginning of daylight saving time.

–Day2 = end of daylight saving time.

•In the Southern hemisphere, month2 must be before month1, as daylight saving time begins in the fall and ends in the spring.

•Specify the exact time that the transition should occur (24 hour clock).

–Time of transition into daylight saving time — according to local standard time.

–Time of transition out of daylight saving time — according to local daylight savings time.

•For the clock summer-time recurring command, the default values are the United States transition rules:

–Daylight saving time begins: 2:00 (AM) on the second Sunday of March.

–Daylight saving time ends: 2:00 (AM) on the first Sunday of November.

How to Define Recurring Daylight Saving Time Transitions

Step 1 From the SCE(config)# prompt, type clock summer-time zone recurring [week1 day1 month1 time1 week2 day2 month2 time2 [offset ]] and press Enter.

Configures daylight saving time to start and stop on the specified days every year.

Defining Recurring Daylight Saving Time Transitions: Example

The following example shows how to configure recurring daylight saving time for a time zone designated "DST" as follows:

•Daylight saving time begins — 0:00 on the last Sunday of March.

•Daylight saving time ends — 23:59 on the Saturday of fourth week of November.

•Offset = 1 hour (default.
SCE(config)# clock summer-time DST recurring last Sunday March 00:00  4 Saturday November 
23:59
How to Define Non-Recurring Daylight Saving Time Transitions

Step 1 From the SCE(config)# prompt, type clock summer-time zone [date1 month1 year1 time1 date2 month2 year2 time2 [offset ]] and press Enter.

Defining Non-Recurring Daylight Saving Time Transitions: Example

The following example shows how to configure non-recurring daylight saving time for a time zone designated "DST" as follows:

•Daylight saving time begins — 0:00 on April 16, 2004.

•Daylight saving time ends — 23:59 October 23, 2004.

•Offset = 1 hour (default)
SCE(config)# clock summer-time DST April 16 2004 00:00 October 23 2004 23:59
How to Cancel the Daylight Saving Time Configuration

Step 1 From the SCE(config)# prompt, type no clock summer-time and press Enter.

Removes all daylight saving configuration.

How to Display the Current Daylight Saving Time Configuration

Step 1 From the SCE# prompt, type show timezone and press Enter.

Displays the current time zone and daylight saving time configuration.

Configuring SNTP

•How to Enable the SNTP Multicast Client

•How to Disable the SNTP Multicast Client

•How to Enable the SNTP Unicast Client

•Disabling the SNTP Unicast Client

•How to Define the SNTP Unicast Update Interval

•How to Display SNTP Information

The Simple Network Timing Protocol (SNTP) is a simple solution to the problem of synchronizing the clocks in the various elements of the network. SNTP provides access to a time source via the network. The system clock and calendar are then set in accordance with this external source.

There are two options for the SNTP client. These functions are independent, and the system employ either one or both.

•Multicast SNTP client — Listens to SNTP broadcasts and updates the system clock accordingly.

•Unicast SNTP client — Sends a periodic request to a configured SNTP server, and updates the system clock according to the server response.

Note It is recommended that an IP access control list be configured to prevent access from unauthorized SNTP or NTP multicast servers (see Configuring Access Control Lists (ACLs)).

The following commands are relevant to SNTP configuration:

•[no] sntp broadcast client

•[no] sntp server address

•no sntp server all

•sntp update-interval

•show sntp

How to Enable the SNTP Multicast Client

Step 1 From the SCE(config)# prompt, type sntp broadcast client and press Enter.

Enables the SNTP multicast client. It will accept time updates from any broadcast server.

How to Disable the SNTP Multicast Client

Step 1 From the SCE(config)# prompt, type no sntp broadcast client and press Enter.

Disables the SNTP multicast client. It will not accept any broadcast time updates.

How to Enable the SNTP Unicast Client

Options

The following option is available:

•ip-address — the IP address of the SNTP unicast server.

Step 1 From the SCE(config)# prompt, type sntp server ip-address and press Enter

Defines the SNTP unicast server so that SNTP client is able to query that server.

Enabling SNTP Unicast Client: Example

The following example shows how to enable an SNTP server at IP address 128.182.58.100.
SCE(config)# sntp server 128.182.58.100
Disabling the SNTP Unicast Client

How to Disable the SNTP Unicast Client and Remove All Servers

Step 1 From the SCE(config)# prompt, type no sntp server all and press Enter.

Removes all SNTP unicast servers, preventing unicast SNTP query.

How to Remove One SNTP Server

Options

The following option is available:

•ip-address — the IP address of the SNTP unicast server.

Step 1 From the SCE(config)# prompt, type no sntp server ip-address and press Enter

Removes the specified SNTP unicast server.

How to Define the SNTP Unicast Update Interval

Options

The following option is available:

•interval — the time in seconds between updates (64 through 1024)

default interval = 64 seconds

Step 1 From the SCE(config)# prompt, type sntp update-interval interval, and press Enter.

Configures the SNTP unicast client to query the server at the defined intervals.

Example

The following example shows how to set the SNTP update interval for 100 seconds.
SCE(config)# sntp update-interval 100
How to Display SNTP Information

Step 1 From the SCE> prompt, type show sntp, and press Enter.

Displays the configuration of both the SNTP unicast client and the SNTP multicast client.

Example

This example illustrates how to use this command.
SCE# show sntp 
SNTP broadcast client: disabled 
last update time: not available 
SNTP unicast client: enabled 
SNTP unicast server: 128.182.58.100 
last update time: Feb 10 2002, 14:06:41 
update interval: 100 seconds
Domain Name Server (DNS) Settings

•Configuring DNS Lookup

•Configuring Name Servers

•How to Add a Host to the Host Table

•How to Display Current DNS Settings

When a name of a host is given as a parameter to a CLI command that expects a host name or an IP address, the system translates the name to an IP address according to the following:

1. If the name is in a dotted decimal notation (that is, in the format x.x.x.x), it is directly translated to an IP address it represents.

2. If the name does not contain the dot character (.), the system looks it up in the IP Host table. If the name is found on the table, it is mapped to the corresponding IP address. The IP host table can be configured using the command ip host.

3. If the name does not contain the dot (.) character, and the domain name function is enabled (See the ip domain-lookup command), and a default domain name is specified (See the ip domain-name command), the default domain name is appended to the given name to form a fully qualified host name. This, in turn, is used to perform a DNS query translating the name to an IP address.

4. Otherwise, if the domain name function is enabled, the name is considered to be fully qualified, and is used to perform a DNS query translating the name to an IP address.

The following commands are relevant to DNS settings:

•ip name-server

•ip domain-name

•no ip domain-name

•ip domain-lookup

•show hosts

Configuring DNS Lookup

How to Enable DNS Lookup

Step 1 From the SCE(config)# prompt, type ip domain-lookup and press Enter.

Enables DNS lookup.

How to Disable DNS Lookup

Step 1 From the SCE(config)# prompt, type no ip domain-lookup and press Enter.

Configuring Name Servers

•Options

•How to Define Domain Name Servers

•How to Remove a Domain Name Server

•How to Remove All Domain Name Servers

Options

The following options are available:

•server-ip-address — The IP address of the domain name server. You can define more than one DNS server (server-ip-address1, server-ip-address2, server-ip-address3)

How to Define Domain Name Servers

Use this command to specify the address of one or more name servers to use for name and address resolution.

Step 1 From the SCE(config)# prompt, type ip name-server server-address1 [server-address2 [server-address3]] and press Enter.

Defines the servers at the specified addresses as domain name servers.

Defining Domain Name Servers: Example

The following example shows how to configure the two name server (DNS) IP addresses.
SCE(config)#ip name-server 10.1.1.60 10.1.1.61
How to Remove a Domain Name Server

Step 1 From the SCE(config)# prompt, type no ip name-server server-address1 [server-address2 [server-address3]] and press Enter.

Removes the specified server from the DNS list.

Removing a Domain Name Server: Example

The following example shows how to remove name server (DNS) IP addresses.
SCE(config)#no ip name-server 10.1.1.60 10.1.1.61
How to Remove All Domain Name Servers

Step 1 From the SCE(config)# prompt, type no ip name-server and press Enter.

Removes all configured DNS servers.

How to Add a Host to the Host Table

Options

The following options are available:

•hostname — The name of the host.

•ip-address — The IP address of the host

Step 1 From the SCE(config)# prompt, type ip host hostname ip-address and press Enter.

Adds the specified host to the host table.

Adding Hosts to Removing them from the Host Table: Example

The following example shows how to add a host to the host table.
SCE(config)#ip host PC85 10.1.1.61
The following example shows how to remove a hostname together with all its IP mappings.
SCE(config)#no ip host PC85
How to Display Current DNS Settings

Step 1 From the SCE# prompt, type show hosts and press Enter.

Displays current DNS settings.

Displaying Current DNS Settings: Example

The following example shows how to display current DNS information.
SCE#show hosts 
Default domain is Cisco.com  
Name/address lookup uses domain service 
Name servers are 10.1.1.60, 10.1.1.61 
Host                 Address 
----                 ------- 
PC85                 10.1.1.61 
sce#
Configuring Cisco Discovery Protocol

Cisco Discovery Protocol (CDP) is a device discovery protocol that runs on Cisco manufactured equipment, and is now supported on the Cisco SCE8000 platform.

•Cisco Discovery Protocol

•Cisco Discovery Protocol on the Cisco SCE8000 Platform

•Configuring CDP on the Cisco SCE8000 Platform

•Monitoring and Maintaining CDP

•CDP Configuration Examples

Cisco Discovery Protocol

CDP is primarily used to obtain protocol addresses of neighboring devices and discover the platform of those devices. It is media- and protocol-independent, and runs on all equipment manufactured by Cisco, including routers, bridges, access servers, and switches.

CDP runs on all media that support Subnetwork Access Protocol (SNAP), including LAN, Frame Relay, and ATM physical media. CDP runs over the data link layer only. Therefore, two systems that support different network-layer protocols can learn about each other.

Each device configured for CDP sends periodic messages, known as advertisements, to a multicast address. Each device advertises at least one address where it can receive SNMP messages. The advertisements also contain time-to-live, or holdtime, information, which indicates the length of time a receiving device should hold CDP information before discarding it. Each device also listens to the periodic CDP messages sent by others in order to learn about neighboring devices and determine when their interfaces to the media go up or down.

CDP Version-2 (CDPv2) is the most recent release of the protocol and provides more intelligent device tracking features. These features include a reporting mechanism that allows for more rapid error tracking, thereby reducing costly downtime. Reported error messages can be sent to the console or to a logging server, and include instances of native VLAN IDs (IEEE 802.1Q) on connecting ports that do not match, and port duplex states between connecting devices that do not match.

Type-Length-Value fields (TLVs) are blocks of information embedded in CDP advertisements. Table 6-1 summarizes the TLV definitions for CDP advertisements.

Table 6-1 Type-Length-Value Definitions for CDPv2

TLV

Definition

Device-ID TLV

Identifies the device name in the form of a character string.

Address TLV

Contains a list of network addresses of both receiving and sending devices.

Port-ID TLV

Identifies the port on which the CDP packet is sent.

Capabilities TLV

Describes the functional capability for the device in the form of a device type, for example, a switch.

Version TLV

Contains information about the software release version on which the device is running.

Platform TLV

Describes the hardware platform name of the device, for example, Cisco 4500.

IP Network Prefix TLV

Contains a list of network prefixes to which the sending device can forward IP packets. This information is in the form of the interface protocol and port number, for example, Eth 1/0.

VTP Management Domain TLV

Advertises the system's configured VTP management domain name-string. Used by network operators to verify VTP domain configuration in adjacent network nodes.

Native VLAN TLV

Indicates, per interface, the assumed VLAN for untagged packets on the interface. CDP learns the native VLAN for an interface. This feature is implemented only for interfaces that support the IEEE 802.1Q protocol.

Full/Half Duplex TLV

Indicates status (duplex configuration) of CDP broadcast interface. Used by network operators to diagnose connectivity problems between adjacent network elements.

Cisco Discovery Protocol on the Cisco SCE8000 Platform

Because the Cisco SCE8000 platform functions differently from a router or a switch, there are several unique features of CDP as supported on this device.

CDP Operational Modes on the Cisco SCE8000

With a typical Cisco device, CDP is either enabled or disabled. When enabled, CDP packets are received and transmitted. When disabled, CDP packets are discarded and no packets are transmitted.

The Cisco SCE8000 is not a typical Cisco device. It is usually installed as a bump-in-the-wire device, and transparently forwards packets from one interface to the corresponding interface. This behavior conflicts with typical Cisco CDP packet processing; a typical Cisco device never forwards CDP packets from one interface to another interface. To accommodate this behavior, the Cisco SCE8000 extends the enabled state with three different CDP modes:

•Standard mode: Standard CDP operation. CDP packets are received and processed, as well as generated.

In this mode CDP functions as it does on a typical Cisco device. This mode should be used in most cases, even though it is not the default mode.

•Bypass mode (default): CDP packets are received and transmitted unchanged. Received packets are not processed. No packets are generated.

In this mode, "bump-in-the-wire" behavior is applied to CDP packets. This is the backward-compatible mode, equivalent to not having CDP support.

•Monitor mode: CDP packets are received, processed, and transmitted unchanged. CDP packets are analyzed and CDP neighbor information is available. No packets are generated.

In this mode "bump-in-the-wire" behavior is applied to CDP packets. This mode may be confusing to operators and network management tools, because it is contrary to the concept of CDP as a physical link protocol.

Table 6-2 summarizes the CDP state and modes behavior in the Cisco SCE8000.

Note When CDP is either not running or disabled at the interface level, CDP packets are discarded and CDP packets are not generated, regardless of the CDP mode.

Table 6-2 CDP Modes in the Cisco SCE8000

CDP Mode

"cdp run" AND "cdp enable"

"no cdp run" OR "no cdp enable"

Standard

Received CDP packets processed

CDP packets generated

Received CDP packets discarded

CDP packets not generated

Bypass (Default)

Received CDP packets bypassed (not processed)

CDP packets not generated

Received CDP packets discarded

CDP packets not generated

Monitor

Received CDP packets processed and bypassed

CDP packets not generated

Received CDP packets discarded

CDP packets not generated

CDP Limitations on the Cisco SCE8000

CDP as currently supported on the Cisco SCE8000 has the following limitations:

•CDP is supported on traffic interfaces only (including cascade ports).

•CDP is currently managed by CLI only. There is currently no SNMP support for CDP on the Cisco SCE8000.

•CDP always sends version 2 CDP packets. However it may receive v1 or v2 packets

Configuring CDP on the Cisco SCE8000 Platform

To configure CDP, perform the tasks in the following sections:

•Enabling CDP Globally

•Setting CDP Mode

•Enabling CDP on a Specific Traffic Interface

•Setting the Hold Time

•Setting the Timer

Enabling CDP Globally

By default, CDP is enabled on the Cisco SCE8000. If you prefer not to use the CDP device discovery capability, use the following command to disable it.

Step 1 From the SCE(config)# prompt, type no cdp run and press Enter.

To re enable CDP after disabling it, use the following command.

Step 1 From the SCE(config)# prompt, type cdp run and press Enter.

Note By default, when you enable CDP, it is set to bypass mode. To change the mode, see Setting CDP Mode.

Setting CDP Mode

The Cisco SCE8000 is usually installed as a bump-in-the-wire device, and therefore forwards packets (including CDP packets) from one interface to the corresponding interface, whereas a typical Cisco device never forwards CDP packets from one interface to another interface. Therefore, the Cisco SCE8000 extends the enabled state with the following three CDP modes:

•standard—function as a typical CDP device

•monitor—monitor the CDP packets

•bypass—bypass the CDP packets

(See CDP Operational Modes on the Cisco SCE8000 for a description of the different CDP modes.)

Caution In cascade topologies, both SCE8000 platforms must be configured to the same CDP mode.

By default, the CDP mode is set to bypass.

To reset the CDP mode to the default mode (bypass) use the default cdp mode command.

To change the CDP mode, use the following command in global configuration mode.

Step 1 From the SCE(config)# prompt, type cdp mode (standard | monitor | bypass) and press Enter.

Enabling CDP on a Specific Traffic Interface

By default, CDP is enabled on all traffic interfaces (see CDP Limitations on the Cisco SCE8000).

To disable CDP on a specific traffic interface, use the no cdp enable command in the appropriate interface configuration mode.

To renewable CDP on a specific interface after disabling it, use the following command in the appropriate interface configuration mode. CDP must be enabled globally on the SCE8000 platform (cdp run command) in order to enable a specific interface.

Step 1 From the SCE(config if)# prompt, type cdp enable and press Enter.

Tip For consistent CDP operation, it is recommended that both ports of any one traffic link be either enabled or disabled.

Setting the Hold Time

Use this command to set the mount of time the receiving device should hold a CDP packet from your router before discarding it. Use either the no or the default form of the command to restore the holdtime to the default value.

Options

The following option is available:

•seconds— Hold time value to be sent in the CDP update packets in seconds.

default = 180 seconds

Step 1 From the SCE(config)# prompt, type cdp holdtime seconds and press Enter.

Setting the Timer

Use this command to configure how often the SCE8000 platform sends CDP updates. Use either the no or the default form of the command to restore the timer to the default value.

Options

The following option is available:

•seconds— How often the SCE8000 platform sends CDP updates, in seconds.

default = 60 seconds

Step 1 From the SCE(config)# prompt, type cdp timer seconds and press Enter.

Monitoring and Maintaining CDP

To monitor and maintain CDP on the Cisco SCE8000, use one or more of the following commands.

The clear commands are in privileged EXEC mode. The show commands are in viewer mode.

Command

Purpose

clear cdp counters

Resets CDP traffic counters to zero

clear cdp table

Clears the table that contains CDP information about neighbors

show cdp

Displays the following information:

•Interval between transmissions of CDP advertisements (transmission timer)

•Number of seconds the CDP advertisement is valid for a given port (hold time)

•Version of the advertisement

•CDP mode

show cdp entry {*|device-name[*] [protocol | version]}

Displays protocol and version information about a specific neighboring device discovered using CDP.

•Use "*" to display all devices.

•Use device-name* to display all devices beginning with device-name.

•Use the protocol keyword to display only protocol information

•Use the version keyword to display only version information.

show cdp neighbors [type number] [detail]

Displays the following information:

•Type of device that was discovered

•Name of the device

•Number and type of the local interface (port)

•Number of seconds the CDP advertisement is valid for the port

•Device type

•Device product number

•Port ID

If you use the detail keyword, the following additional information is displayed:

•Entry address(es)

•[Network protocol] address

•Version

•Advertisement version

•Native VLAN ID

•Duplex mode

•VTP domain name associated with neighbor devices.

show cdp traffic

Displays the following information:

•Total CDP packets output

•Total CDP packets input

•Number of CDP advertisements with bad headers

•Number of times the checksum operation failed

•Number of times CDP failed to send advertisements

•Number of times the local device did not have enough memory to store the CDP advertisements

•Number of invalid CDP advertisements

•Number of times fragments of CDP advertisement were received

•CDP version 1 advertisements output

•CDP version 1 advertisements input

•CDP version 2 advertisements output

•CDP version 2 advertisements input

CDP Configuration Examples

Example: Setting the CDP Mode

The following example illustrates how to configure CDP mode to `standard'.

Caution In cascade topologies, both SCE8000 platforms must be configured to the same CDP mode.

The show command verifies that the CDP configuration has been correctly updated.
sce(config)# cdp mode standard
sce(config)# do show cdp 
Global CDP information:
Sending CDP packets every 60 seconds
        Sending a holdtime value of 180 seconds
        Sending CDPv2 advertisements is enabled
standard mode - CDP packets are received and processed. CDP packets are generated.
Example: Monitoring and Maintaining CDP

The following example shows a typical series of steps for viewing information about CDP neighbors.

Table 6-3 describes the significant fields shown in the output of the show cdp neighbors command.
sce> show cdp   
Global CDP information:
        Sending CDP packets every 60 seconds
        Sending a holdtime value of 180 seconds
        Sending CDPv2 advertisements is enabled
        standard mode - CDP packets are received and processed. CDP packets are generated.
sce> show cdp neighbors 
Capability Codes: R - Router, T - Trans Bridge, B - Source Route Bridge
                  S - Switch, H - Host, I - IGMP, r - Repeater, P - Phone
Device ID        Local Intrfce     Holdtme    Capability  Platform  Port ID
Lab-Router       Gig 3/0/0          169         R S I     ME-C6524GSGig 1/5
Lab-Router       Gig 3/0/1          169         R S I     ME-C6524GSGig 1/6
Lab-Router       Gig 3/0/2          169         R S I     ME-C6524GSGig 1/7
Lab-Router       Gig 3/0/3          169         R S I     ME-C6524GSGig 1/8
sce>
Table 6-3 show cdp neighbors Field Description

Field

Definition

Device ID

The name of the neighbor device and either the MAC address or the serial number of this device.

Local Intrfce

The protocol being used by the connectivity media.

Holdtme

The remaining amount of time (in seconds) the current device will hold the CDP advertisement from a sending router before discarding it.

Capability (Capability Codes)

Capability (type of routing device) of the listed neighboring device.

The capability types that can be discovered are:

R—Router

T—Transparent bridge

B—Source-routing bridge

S—Switch

H—Host

I— device is using IGMP

r—Repeater

Note The capability of the SCE8000 is `r' (Repeater), since it is installed as a bump-in-the-wire device.

Platform

The product number of the device.

Port ID

The protocol and port number of the device.