Cisco SCE8000 10GBE Software Configuration Guide, Release 3.7.x
Global Configuration
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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

Enabling the CLI Interface Warning Banner

OS Fingerprinting and NAT Detection

Restrictions and Limitations

Configuring OS Fingerprinting

Monitoring OS Fingerprinting

Global Configuration

Revised: February 07, 2014, OL-24150-12

IP Routing Configuration

Configuring 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.

From the SCE(config)# prompt, type:

 

Command
Purpose

ip default-gateway ip-address

Configures the default gateway.

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.

From the SCE(config)# prompt, type:

 

Command
Purpose

ip route prefix mask next-hop

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 Entire IP Routing Table

From the SCE# prompt, type:

 

Command
Purpose

show ip route

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

From the SCE# prompt, type:

 

Command
Purpose

show ip route prefix mask

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

From the SCE(config)# prompt, type:

 

Command
Purpose

ip advertising

Enables IP advertising.

How to Configure the IP Advertising Destination

From the SCE(config)# prompt, type:

 

Command
Purpose

ip advertising destination destination

Configures the destination for the IP advertising pings.

How to Configure the IP Advertising Interval

From the SCE(config)# prompt, type:

 

Command
Purpose

ip advertising interval interval

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

From the SCE# prompt, type:

 

Command
Purpose

show ip advertising

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

Configuring Time Clocks and Time Zone

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

From the SCE(config)# prompt, type:

 

Command
Purpose

show clock

Displays system time.

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

From the SCE(config)# prompt, type:

 

Command
Purpose

show calendar

Displays calendar time.

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

From the SCE# prompt, type:

 

Command
Purpose

clock set time-date

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

From the SCE(config)# prompt, type:

 

Command
Purpose

clock timezone zone hours minutes

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

From the SCE(config)# prompt, type:

 

Command
Purpose

no clock timezone

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

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

From the SCE(config)# prompt, type:

 

Command
Purpose

clock summer-time zone recurring [week1 day1 month1 time1 week2 day2 month2 time2 [ offset ]]

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

From the SCE(config)# prompt, type:

 

Command
Purpose

clock summer-time zone [ date1 month1 year1 time1 date2 month2 year2 time2 [ offset ]]

Defines non-recurring daylight saving time transitions.

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

From the SCE(config)# prompt, type:

 

Command
Purpose

no clock summer-time

Removes all daylight saving configuration.

How to Display the Current Daylight Saving Time Configuration

From the SCE# prompt, type:

 

Command
Purpose

show timezone

Displays the current time zone and daylight saving time configuration.

Configuring SNTP

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

From the SCE(config)# prompt, type:

 

Command
Purpose

sntp broadcast client

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

How to Disable the SNTP Multicast Client

From the SCE(config)# prompt, type:

 

Command
Purpose

no sntp broadcast client

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.

From the SCE(config)# prompt, type:

 

Command
Purpose

sntp server ip-address

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

From the SCE(config)# prompt, type:

 

Command
Purpose

no sntp server all

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.

From the SCE(config)# prompt, type:

s

Command
Purpose

no sntp server ip-address

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

From the SCE(config)# prompt, type;

 

Command
Purpose

sntp update-interval interval

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

From the SCE> prompt, type:

 

Command
Purpose

show sntp

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

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

From the SCE(config)# prompt, type:

 

Command
Purpose

ip domain-lookup

Enables DNS lookup.

How to Disable DNS Lookup

From the SCE(config)# prompt, type:

 

Command
Purpose

no ip domain-lookup

Disables DNS lookup.

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.

From the SCE(config)# prompt, type:

 

Command
Purpose

ip name-server server-address1 [server-address2 [server-address3]]

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

From the SCE(config)# prompt, type:

 

Command
Purpose

no ip name-server server-address1 [server-address2 [server-address3]]

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

From the SCE(config)# prompt, type:

 

Command
Purpose

no ip name-server

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

From the SCE(config)# prompt, type:

 

Command
Purpose

ip host hostname ip-address

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

From the SCE# prompt, type:

 

Command
Purpose

show hosts

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

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

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.

From the SCE(config)# prompt, type:

 

Command
Purpose

no cdp run

Disables CDP.

To reenable CDP after disabling it, use the following command.

From the SCE(config)# prompt, type:

 

Command
Purpose

cdp run

Enables CDP.


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.

From the SCE(config)# prompt, type:

 

Command
Purpose

cdp mode (standard | monitor | bypass)

Changes the CDP mode.

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 interface, use the no cdp enable command in the appropriate interface configuration mode.

To reenable 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.

From the SCE(config if)# prompt, type:

 

Command
Purpose

cdp enable

Enables CDP on a specific interface.


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

From the SCE(config)# prompt, type:

 

Command
Purpose

cdp holdtime seconds

Sets hold time.

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

From the SCE(config)# prompt, type:

 

Command
Purpose

cdp timer seconds

Sets the timer.

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 Ten 3/0/0 169 R S I CISCO7604 Ten 3/1
Lab-Router Ten 3/1/0 169 R S I CISCO7604 Ten 3/2
Lab-Router Ten 3/2/0 169 R S I CISCO7604 Ten 3/3
Lab-Router Ten 3/3/0 169 R S I CISCO7604 Ten 3/4
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.

Enabling the CLI Interface Warning Banner

A warning banner is a message displayed when the user connects to the SCE using either Telnet or the console connection. It serves as a security warning for unauthorized users trying to connect to SCE platform. It can also provide device details, as well as information about the service and application.

By default the banner is disabled. You do not have to shutdown the SCE platform in order to enable or disable the banner.

From the SCE(config)# prompt, type:

 

Command
Purpose

banner login “ banner-text"

Enables the display of the specified text as the warning banner when the CLI interface is accessed.

Banner text should be enclosed in quotation marks or other delimiting characters.

OS Fingerprinting and NAT Detection

OS fingerprinting is the process of determining the identity of a remote host operating system by analyzing packets from that host. It detects the operating system used by the subscriber and whether the subscriber is present in a NAT environment by analyzing subscriber traffic. NAT detection is based on whether the same subscriber is connecting using multiple operating systems.

An encrypted fingerprint file that has the list of OS signatures is packaged with each SCOS release. Signature files are updated as needed, and the updated signature files are available on cisco.com.

The detected OS type is reported using the following mechanisms:

  • RDRs—The subscriber OS type is reported in the Real-time Subscriber Usage RDR (SUR). These RDRs can be stored by the CM and interpreted using Insight.
  • CLI—The subscriber OS type is available through OS fingerprinting and party info commands.
  • VSA—Over mobile interfaces, the OS type is sent as a VSA in CCR-U over Gx.
  • SCA BB Console—The OS type is available through an API that displays the OS type on the SCA BB console as part of the status of a subscriber.

Restrictions and Limitations

Due to the nature of the SCE platform, there are certain limitations to the scope of the OS fingerprinting and NAT detection feature:

  • OS information is available only for logged-in and active subscribers.
  • OS fingerprinting is not done continuously for any subscriber. If a subscriber changes OS or moves to a NAT environment during the time when they are not sampled, OS type or NAT environment cannot be detected.
  • OS fingerprinting depends mainly on the parameters in the TCP-SYN packets. The signature database is built based on the default settings used by various operating systems. If the subscriber changes default parameters, such as TCP window size, through registries, it may lead to misclassification of the OS.
  • The OS type will not be detected in any of the following situations:

If the subscriber connects to the internet using an http-proxy, or if there is a proxy or gateway that changes L3/L4 packets of the subscriber.

If the subscriber has only one flow.

If the subscriber has only UDP flows

  • In case of multiple IP or IP range subscribers, OS fingerprinting is done only for a limited number IP addresses (default is 5).
  • NAT detection is based on whether the same subscriber is connecting using multiple operating systems. Therefore, if all the users behind a NAT use the same OS, it is not possible to detect the NAT.
  • When a subscriber runs multiple operating systems using vmware, it may be detected as a NAT even though the subscriber is not in NAT environment.

Configuring OS Fingerprinting

By default, the OS fingerprinting feature is disabled. When OS fingerprinting is enabled, you can also configure the following OS fingerprinting parameters:

  • Sampling window—How long flows from a subscriber are fingerprinted
  • Sampling interval—Interval between OS fingerprinting sampling windows

OS fingerprinting is done for "sampling window" seconds every "sampling interval" minutes.

  • NAT detection window—Time period within which detecting multiple operating systems for the same subscriber or IP address triggers NAT identification
  • OS flush time–Time interval after which OS information is flushed from the system
  • Signature file—Name of OS fingerprint signature file
  • Scan port—Port used for opening OS fingerprinting flows
  • GX reporting—Enable sending subscriber OS information in Gx messages

SUMMARY STEPS

1. enable

2. configure

3. interface linecard 0

4. os-fingerprinting

5. (Optional) os-fingerprinting sampling window window interval interval

6. (Optional) os-fingerprinting NAT-detection-window time

7. (Optional) os-fingerprinting os-flush-time time

8. (Optional) os-fingerprinting signature-file filename

9. (Optional) os-fingerprinting scan-port port#

10. (Optional) os-fingerprinting gx-report

DETAILED STEPS

 

Command
Purpose

Step 1

enable

Example:

SCE> enable

Enables privileged EXEC mode. Enter your password when prompted.

Step 2

configure

Example:

SCE# configure

Enters global configuration mode.

Step 3

interface linecard

Example:

SCE(config)# interface linecard 0

Enters interface linecard configuration mode.

Step 4

os -fingerprinting

Example:

SCE(config if)# os-fingerprinting

Enables OS fingerprinting and loads the default.fp signature file.

Step 5

os -fingerprinting sampling window window interval interval

Example:

SCE(config if)# os-fingerprinting sampling window 60 interval 5

(Optional) Configures the following:

  • Length of the OS sampling window, in seconds (10-300)
  • Interval between sampling windows, in minutes (10-1440)

Step 6

os -fingerprinting NAT-detection-window time

Example:

SCE(config if)# os-fingerprinting NAT-detection-window 600

(Optional) Enables NAT detection and configures the time period, in seconds, within which detecting multiple operating systems for one subscriber will trigger NAT identification. (10-300)

Step 7

os -fingerprinting os-flush-time time

Example:

SCE(config if)# os-fingerprinting os-flush-time 3

(Optional) Enables flushing the OS fingerprinting information and configures the time interval, in days, after which OS fingerprinting information is flushed from the system. (1-5)

Step 8

os -fingerprinting signature-file filename

Example:

SCE(config if)# os-fingerprinting signature-file new-signature-file

(Optional) Specifies the signature file used for OS fingerprinting.

Step 9

os -fingerprinting scan-port port#

Example:

SCE(config if)# os-fingerprinting scan-port 50

(Optional) Configures the port used for opening OS fingerprinting flows. The port numbers can be in the range of 0 - 65535. However, the following port numbers are blocked, and cannot be used for OS fingerprinting:

20, 21, 194, 554, 651, 654, 1720, 1755, 2000, 2948, 2949, 4374, 5060, 5061.
For more information on this command, see the Cisco SCE8000 CLI Command Reference, Release 3.7.x .

Step 10

os -fingerprinting gx-report

Example:

SCE(config if)# os-fingerprinting gx-report

(Optional) Enables sending subscriber OS information in Gx messages.

Monitoring OS Fingerprinting

To monitor OS fingerprinting, use one or more of the following commands.

These commands are in viewer mode.

 

Command
Purpose

show os-fingerprinting config

Displays the current OS fingerprinting configuration.The following information is displayed:

  • State of OS fingerprinting (enabled or disabled)
  • Sampling period
  • Sampling interval
  • NAT detection window
  • OS flush time
  • OS fingerprinting port
  • Signature file

show os-finger-printing signature-file

Displays the unencrypted contents of the signature file.

show interface linecard slot-number subscriber name name [os-info]

Displays information about a specified subscriber, including detected OS. To display only the OS fingerprinting information, use the os-info option .

show os-finger-printing subscriber-name name

Displays the OS fingerprinting information for the specified subscriber. This command displays the same information as the show interface linecard slot-number subscriber name name command with the os-info option.