Cisco IOS XR Interface and Hardware Component Configuration Guide, Release 3.6
Configuring SRP Interfaces on Cisco IOS XR Software
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Configuring SRP Interfaces on Cisco IOS XR Software

Table Of Contents

Configuring SRP Interfaces on Cisco IOS XR Software

Contents

Prerequisites for Configuring SRP Interfaces

Information About Configuring SRP Interfaces

How to Configure an SRP Interface

Enabling SRP on a Port

Restrictions

Creating a Basic SRP Configuration

Configuring Intelligent Protection Switching (IPS)

Configuring Modular Quality of Service CLI (MQC) with SRP

Adding a Node to the Ring

Configuration Examples for SRP Interfaces

Configuring SRP: Example

Configuring Modular QoS with SRP: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance


Configuring SRP Interfaces on Cisco IOS XR Software


This module describes how to configure the Spatial Reuse Protocol (SRP) on supported Cisco Dynamic Packet Transport (DPT) interfaces in routers running Cisco IOS XR software.

SRP is a MAC-layer protocol developed by Cisco and is used in conjunction with Cisco DPT products. DPT products deliver scalable Internet service, reliable IP-aware optical transport, and simplified network operations. These solutions allow you to scale and distribute your IP services across a reliable optical packet ring infrastructure.


Note Throughout the remainder of this publication, the term SRP is used to describe features related to DPT products.


Feature History for Configuring SRP Interfaces on Cisco IOS XR Software

Release
Modification

Release 3.2.2

This feature was introduced on the Cisco CRS-1 and is supported only on the 4-port OC-192c/STM-64c POS/DPT PLIM.

Release 3.4.0

This command was first supported on the 16-port OC-48c/STM-16c POS/DPT PLIM.

Release 3.5.0

No modifications.

Release 3.6.0

No modifications.


Contents

Prerequisites for Configuring SRP Interfaces

Information About Configuring SRP Interfaces

How to Configure an SRP Interface

Configuration Examples for SRP Interfaces

Additional References

Prerequisites for Configuring SRP Interfaces

Before configuring SRP interfaces, be sure that the following conditions are met:

You must be in a user group associated with a task group that includes the proper task IDs for SRP commands. Task IDs for commands are listed in the SRP Commands on Cisco IOS XR Software.

You know the interface IP address you will assign to the new SRP interface configuration.

The hardware that you are using supports SRP. As of Cisco IOS XR Software Release 3.6, SRP is supported on the 4-port OC-192c/STM-64c POS/DPT PLIM and the 16-port OC-48c/STM-16c POS/DPT PLIM.

Information About Configuring SRP Interfaces

Spatial bandwidth reuse is possible due to the packet destination-stripping property of SRP. Older technologies incorporate source stripping, where packets traverse the entire ring until they are removed by the source. Even if the source and destination nodes are next to each other on the ring, packets continue to traverse the entire ring until they return to the source to be removed. SRP provides more efficient use of available bandwidth by having the destination node remove the packet after it is read. This provides more bandwidth for other nodes on the SRP ring.

SRP rings consists of two counter rotating fibers, known as outer and inner rings, both concurrently used to carry data and control packets. SRP uses both explicit control packets and control information piggybacked inside data packets (control packets handle tasks such as keepalives, protection switching, and bandwidth control propagation). Control packets propagate in the opposite direction from the corresponding data packets, ensuring that the data takes the shortest path to its destination. The use of dual fiber-optic rings provides a high level of packet survivability. In the event of a failed node or a fiber cut, data is transmitted over the alternate ring.

SRP rings are media independent and can operate over a variety of underlying technologies, including SONET/SDH, wavelength division multiplexing (WDM), and dark fiber. This ability to run SRP rings over any embedded fiber transport infrastructure provides a path to packet-optimized transport for high- bandwidth IP networks. Figure 1 shows an SRP ring created with the Cisco CRS-1 and Cisco XR 12000 Series Routers.

To distinguish between the two rings, one is referred to as the "inner" ring and the other as the "outer" ring. SRP operates by sending data packets in one direction (downstream) and sending the corresponding control packets in the opposite direction (upstream) on the other fiber. This allows SRP to use both fibers concurrently to maximize bandwidth for packet transport and to accelerate control signal propagation for adaptive bandwidth utilization, and for self-healing purposes.

As shown in Figure 1, an SRP node uses SRP Side A to receive (RX) outer ring data and transmit (TX) inner ring data. The node uses SRP Side B to receive (RX) inner ring data and transmit (TX) outer ring data. Side A on one node connects to Side B on an adjacent SRP node.

The commands for configuring SRP interfaces are provided in the Cisco IOS XR Interface and Hardware Component Command Reference.

Figure 1 SRP Ring Example

1

Cisco CRS-1

2

Cisco XR 12000 or 12000 Series Router


How to Configure an SRP Interface

This section contains the following procedures:

Enabling SRP on a Port (required)

Creating a Basic SRP Configuration (required)

Configuring Intelligent Protection Switching (IPS) (optional)

Configuring Modular Quality of Service CLI (MQC) with SRP (optional)

Adding a Node to the Ring (optional)

Enabling SRP on a Port

To enable the use of SRP, you must perform this task. By default, POS/DPT PLIMs support only POS.

Restrictions

On the 4-port OC-192c/STM-64c POS/DPT PLIM, each port pair (0 and 1 or 2 and 3) must be configured the same. If you configure port 0 to be SRP and do not configure port 1 to be SRP, the configuration does not work.

On the 16-port OC-48c/STM-16c POS/DPT PLIM, each group of four ports must be configured the same. If you want to use ports 0 and 1 as a single SRP interface, you must configure all four ports: 0, 1, 2, and 3 to be SRP. Similarly, ports 4-7, 8-11, and 12-15 must be configured the same, as either SRP or POS, for the configuration to work.

SUMMARY STEPS

1. configure

2. hw-module port port-number-1 srp location instance

3. hw-module port port-number-2 srp location instance

4. hw-module port port-number-3 srp location instance

5. hw-module port port-number-4 srp location instance

6. end
or
commit

7. hw-module location node-id reload

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

configure

Example:

RP/0/RP0/CPU0:router# configure

Enters global configuration mode.

Step 2 

hw-module port port-number-1 srp location instance

Example:

RP/0/RP0/CPU0:router(config)# hw-module port 0 srp location 0/5/cpu0

Enables SRP functionality on the first port.

Note An SRP interface requires two consecutive physical ports for proper configuration. The first, lower-numbered port must be even, for example 0 or 2.

Note On the 16-port OC-48c/STM-16c POS/DPT PLIM, groups of four consecutive ports must be configured the same: ports 0-3, 4-7, 8-11 and 12-15.

Step 3 

hw-module port port-number-2 srp location instance

Example:

RP/0/RP0/CPU0:router(config)# hw-module port 1 srp location 0/5/cpu0

Enables SRP functionality on the second port.

Note An SRP interface requires two consecutive physical ports for proper configuration. The second, higher-numbered port must be odd.

Note On the 16-port OC-48c/STM-16c POS/DPT PLIM, groups of four consecutive ports must be configured the same: ports 0-3, 4-7, 8-11, and 12-15.

Step 4 

hw-module port port-number-3 srp location instance

Example:

RP/0/RP0/CPU0:router(config)# hw-module port 2 srp location 0/5/cpu0

Enables SRP functionality on the third port, for 16-port OC-48c/STM-16c POS/DPT PLIMs.

Note An SRP interface requires two consecutive physical ports for proper configuration. The first, lower-numbered port must be even; for example, 0 or 2.

Note On the 16-port OC-48c/STM-16c POS/DPT PLIM, groups of four consecutive ports must be configured the same: ports 0-3, 4-7, 8-11, and 12-15.

Step 5 

hw-module port port-number-4 srp location instance

Example:

RP/0/RP0/CPU0:router(config)# hw-module port 3 srp location 0/5/cpu0

Enables SRP functionality on the fourth port, for 16-port OC-48c/STM-16c POS/DPT PLIMs.

Note An SRP interface requires two consecutive physical ports for proper configuration. The second, higher-numbered port must be odd.

Note On the 16-port OC-48c/STM-16c POS/DPT PLIM, groups of four consecutive ports must be configured the same: ports 0-3, 4-7, 8-11, and 12-15.

Step 6 

end

or

commit

Example:

RP/0/RP0/CPU0:router(config)# end

or

RP/0/RP0/CPU0:router(config)# commit

Saves configuration changes.

When you issue the end command, the system prompts you to commit changes:

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? [cancel]:
 
        

Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.

Step 7 

hw-module location node-id reload

Example:

RP/0/RP0/CPU0:router# hw-module location 0/5/cpu0 reload

Reloads the PLIM and makes the hw-module port command become effective.


Note You must reload the PLIM to enable this configuration change and create the SRP interface.


After you complete this procedure, the following SRP interfaces are available to be configured on the PLIM in slot 5:

0/5/0/0, which comprises ports 0/5/0/0 and 0/5/0/1

0/5/0/2, which comprises ports 0/5/0/2 and 0/5/0/3

Creating a Basic SRP Configuration

This task explains how to create a basic SRP configuration. There are many other possible parameters that can be set and only the most basic are illustrated in this task.


Note You must enable SRP on the interface before you can perform this task. See Enabling SRP on a Port.


SUMMARY STEPS

1. show interfaces

2. configure

3. controller sonet instance clock source internal

4. interface srp instance

5. ipv4 address ip-address mask

6. srp topology-timer value

7. no shutdown

8. end
or
commit

9. show interfaces srp instance

10. show running-config

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

show interfaces

Example:

RP/0/RP0/CPU0:router# show interfaces

(Optional) Displays configured interfaces.

Also use this command to confirm that the router recognizes the PLIM card.

Step 2 

configure

Example:

RP/0/RP0/CPU0:router# configure

Enters global configuration mode.

Step 3 

controller sonet instance clock source internal

Example:

RP/0/RP0/CPU0:router(config)# controller sonet 0/1/0/0 clock source internal

RP/0/RP0/CPU0:router(config)# controller sonet 0/1/0/1 clock source internal

Configures the SONET port transmit clock source for each port comprising the SRP interface. The controller instance is in the notation rack/slot/module/port, and the internal keyword specifies internal clock.

Note Internal clocking is required for SRP interfaces.

Note Refer to Configuring Clear Channel SONET Controllers on Cisco IOS XR Software for more detailed information on the SONET controller configuration.

Step 4 

interface srp instance

Example:

RP/0/RP0/CPU0:router(config)# interface srp 0/1/0/0

Specifies the SRP interface name and notation rack/slot/module/port, and enters interface configuration mode.

Step 5 

ipv4 address ip-address

Example:

RP/0/RP0/CPU0:router(config-if)# ipv4 address 10.1.2.1 255.255.255.224

Assigns an IP address and subnet mask to the interface.

Step 6 

srp topology-timer value

Example:

RP/0/RP0/CPU0:router(config-if)# srp topology-timer 1

(Optional) Specifies how frequently topology discovery messages are sent around the ring to identify the current nodes on the SRP ring.

Step 7 

no shutdown

Example:

RP/0/RP0/CPU0:router(config-if)# no shutdown

Removes the shutdown configuration.

The removal of the shutdown configuration removes the forced administrative down state on the interface, enabling it to move to an up or down state.

Step 8 

end

or

commit

Example:

RP/0/RP0/CPU0:router(config-if)# end

or

RP/0/RP0/CPU0:router(config-if)# commit

Saves configuration changes.

When you issue the end command, the system prompts you to commit changes:

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? [cancel]:
 
        

Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.

Step 9 

show interfaces srp instance

Example:

RP/0/RP0/CPU0:router# show interfaces srp 0/1/0/0

(Optional) Displays the SRP interface configuration.

Step 10 

show running-config

Example:

RP/0/RP0/CPU0:router# show running-config

(Optional) Displays the configuration information currently running on the router.

Configuring Intelligent Protection Switching (IPS)

Perform this task to configure IPS on an SRP interface. This is an optional task.

Intelligent Protection Switching (IPS) provides IP self-healing and restoration, and performance monitoring after a link or node failure. There are two SRP IPS modes:

Automatic SRP IPS mode takes effect when the SRP ring detects an event, a fiber cut, or a node failure, and remains in effect until the trigger condition is cleared. Once the trigger is cleared, the SRP IPS mode remains in effect until the wait-to-restore (WTR) value expires.

User-configured SRP IPS mode takes effect as soon as you enter the command and remains in effect until it is removed by a user command or overridden by an SRP IPS command with higher priority. You can use the no srp ips request forced-switch global configuration command or the srp remove manual-switch EXEC command to negate a user-configured command.

A a user-configured, forced-switch adds a high-priority protection switch wrap on each end of a specified span by entering the user-configured srp ips request forced-switch command. For example, you can enter an srp ips request forced-switch command to force data traffic to one side of the ring before a DPT PLIM is removed from a router slot, or in response to an event.

Table 1 describes the IPS requests in the order of priority, from higher to lower.

Table 1 Explanation of SRP IPS User Requests

SRP IPS Request
Description

Forced-switch

Adds a high-priority protection switch wrap on each end of a specified span by entering the user-configured srp ips request forced-switch command.

Manual-switch

Adds a low-priority protection switch wrap on each end of a specified span by entering the user-configured srp request manual-switch command.



Note Before removing the DPT PLIM, you can use the srp ips request forced-switch command on both sides of the interface that is to be removed.


If an automatic or user-configured protection switch is requested for a given span, the node that receives the protection request issues a protection request to the node on the other end of the span using both the short path over the failed span, because the failure may be unidirectional, and the long path around the ring.

As the protection requests travel around the ring, the protection hierarchy is applied. For example, if a high-priority Signal Fail (SF) request enters the ring, it overrides a preexisting lower-priority request. If an event or a user-configured command enters a low-priority request, it is not allowed if a high-priority request is present on the ring.


Note An exception is that multiple signal-fail and forced-switch requests can coexist on the SRP ring and will bisect the ring if they occur on separate fiber links.


All protection switches are performed bidirectionally and enter wraps at both ends of a span for transmit and receive directions, even if a failure is only unidirectional.

SUMMARY STEPS

1. configure

2. interface srp instance

3. srp ips wtr-timer seconds

4. srp ips timer seconds

5. srp ips request forced-switch {a | b}

6. end
or
commit

7. srp {request | remove} manual-switch {a | b} interface srp instance

8. show srp ips interface srp instance

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

configure

Example:

RP/0/RP0/CPU0:router# configure

Enters global configuration mode.

Step 2 

interface srp instance

Example:

RP/0/RP0/CPU0:router(config)# interface srp 0/1/0/0

Specifies the SRP interface name in the notation rack/slot/module/port and enters interface configuration mode.

Step 3 

srp ips wtr-timer seconds

Example:

RP/0/RP0/CPU0:router(config-if)# srp ips wtr-timer 60

(Optional) Configures the amount of time in seconds that a wrap remains in place after the cause of the wrap is removed.

Step 4 

srp ips timer seconds

Example:
RP/0/RP0/CPU0:router(config-if)# srp ips timer 
60 a

(Optional) Specifies the frequency of the transmission of IPS requests. The default is 1 second.


Note We recommend that the IPS timer value be the same for all nodes on a ring. Therefore, if the IPS timer value is changed on one node, you should change it for all nodes on the ring using srp ips timer command.


Step 5 

srp ips request forced-switch {a | b}

Example:

RP/0/RP0/CPU0:router(config-if)# srp ips request forced-switch a

(Optional) Adds a high-priority protection switch wrap on each end of a specified span.

Note Use this command only as necessary, as it disables the node.

Step 6 

end

or

commit

Example:

RP/0/RP0/CPU0:router(config-if)# end

or

RP/0/RP0/CPU0:router(config-if)# commit

Saves configuration changes.

When you issue the end command, the system prompts you to commit changes:

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? [cancel]:
 
        

Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.

Step 7 

srp {request | remove} manual-switch {a | b} interface srp instance

Example:

RP/0/RP0/CPU0:router# srp remove manual-switch a interface srp 0/1/0/0

(Optional) Adds or removes a low-priority protection switch wrap on each end of a specified span.

Note Use this command only as necessary.

Step 8 

show srp ips interface srp instance

Example:

RP/0/RP0/CPU0:router# show srp ips interface srp 0/1/0/0

(Optional) Displays the IPS configuration on the SRP interface.

Configuring Modular Quality of Service CLI (MQC) with SRP

Perform this task to configure quality-of-service (QoS) classifications with SRP using the Modular QoS command-line interface (MQC) feature. This is an optional task.


Note For more information regarding MQC, refer to Configuring Modular Quality of Service Packet Classification on Cisco IOS XR Software and Cisco IOS XR Modular Quality of Service Command Reference.


SUMMARY STEPS

1. configure

2. class-map match-any access-group-name

3. match mpls experimental topmost exp-value

4. exit

5. class-map match-any access-group-name

6. match precedence precedence-value

7. exit

8. policy-map policy-name

9. class class-name

10. police cir kbps

11. set cos cos-value

12. priority

13. exit

14. class class-name

15. priority

16. set cos cos-value

17. exit

18. exit

19. interface srp instance

20. service-policy output policy-map

21. end
or
commit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

configure

Example:

RP/0/RP0/CPU0:router# configure

Enters global configuration mode.

Step 2 

class-map match-any class-map-name

Example:

RP/0/RP0/CPU0:router(config)# class-map match-any voice

Enters class map configuration mode.

Creates a class map to be used for matching packets to the class whose name you specify.

If you specify match-any, one of the match criteria must be met for traffic entering the traffic class to be classified as part of the traffic class.

Step 3 

match mpls experimental topmost exp-value

Example:

RP/0/RP0/CPU0:router(config-cmap)# match mpls experimental topmost 4

Configures a class map so that the three-bit experimental (EXP) field in the topmost Multiprotocol Label Switching (MPLS) labels are examined for EXP field values.

The EXP value argument is specified as the exact value from 0 to 7.

Step 4 

exit

Example:

RP/0/RP0/CPU0:router(config-cmap)# exit

Exits the current submode.

Step 5 

class-map match-any class-map-name

Example:

RP/0/RP0/CPU0:router(config)# class-map match-any ctrl

Enters class map configuration mode.

Creates a class map to be used for matching packets to the class whose name you specify.

If you specific match-any, one of the match criteria must be met for traffic entering the traffic class to be classified as part of the traffic class.

Step 6 

match precedence precedence-value

Example:

RP/0/RP0/CPU0:router(config-cmap)# match precedence internet

(Optional) Identifies IP precedence values as match criteria.

The range is from 0 to 63.

Reserved keywords can be specified instead of numeric values.

Step 7 

exit

Example:

RP/0/RP0/CPU0:router(config-cmap)# exit

Exits the current submode.

Step 8 

policy-map policy-name

Example:

RP/0/RP0/CPU0:router(config)# policy-map srp-policy

Enters policy map configuration mode.

Creates or modifies a policy map that can be attached to one or more interfaces to specify a service policy.

Step 9 

class class-name

Example:

RP/0/RP0/CPU0:router(config-pmap)# class voice

Specifies the name of the class whose policy you want to create or change.

Step 10 

police cir kbps

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# police cir 2000000

Configures traffic policing.

Note 2000000 represents 10 percent of the interface line rate.

Step 11 

set cos cos-value

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# set cos 4

Sets the Layer 2 class of service (CoS) value of an outgoing packet.

Step 12 

priority

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# priority

Gives priority to a class of traffic belonging to a policy map.

Note The priority command should only be used if the set cos command is also used and specifies a cos value greater then or equal to 2.

Step 13 

exit

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# exit

Exits the current submode.

Step 14 

class class-name

Example:

RP/0/RP0/CPU0:router(config-pmap)# class ctrl

Specifies the name of the class whose policy you want to create or change.

Step 15 

priority

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# priority

Gives priority to a class of traffic belonging to a policy map.

Note The priority command should only be used if the set cos command is also used and specifies a cos value greater than or equal to 2.

Step 16 

set cos cos-value

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# set cos 6

Sets the Layer 2 CoS value of an outgoing packet.

Step 17 

exit

Example:

RP/0/RP0/CPU0:router(config-pmap-c)# exit

Exits the current submode.

Step 18 

exit

Example:

RP/0/RP0/CPU0:router(config-pmap)# exit

Exits the current submode.

Step 19 

interface srp instance

Example:

RP/0/RP0/CPU0:router(config)# interface srp 0/1/0/0

Specifies the SRP interface in the notation rack/slot/module/port and enters interface configuration mode.

Step 20 

service-policy output policy-map

Example:

RP/0/RP0/CPU0:router(config-if)# service-policy output srp-policy

Attaches a policy map to an input or output interface to be used as the service policy for that interface.

The traffic policy evaluates all traffic leaving that interface.

Step 21 

end

or

commit

Example:

RP/0/RP0/CPU0:router(config-if)# end

or

RP/0/RP0/CPU0:router(config-if)# commit

Saves configuration changes.

When you issue the end command, the system prompts you to commit changes:

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? [cancel]:
 
        

Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.

Adding a Node to the Ring

This task describes how to add a node to an existing SRP ring, using Cisco IOS XR commands that insert forced-switch wraps away from the area on the fiber where the node is being added, to ensure a minimal loss of data traffic.

For the purpose of this example, a fifth node is added to a four-node ring. Node 5 is added between Node 1 and Node 4. Figure 2 and Figure 3 show the physical configuration using a single DPT PLIM. Figure 4 and Figure 5 show the logical configuration.

SUMMARY STEPS

1. configure

2. interface srp instance

3. srp ips request forced-switch {a | b}

4. end
or
commit

5. interface srp instance

6. no srp ips request forced-switch {a | b}

7. end
or
commit

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

configure

Example:

RP/0/RP0/CPU0:router1# configure

Enters global configuration mode.

Step 2 

interface srp instance

Example:

RP/0/RP0/CPU0:router1(config)# interface srp 0/1/0/0

Specifies the SRP interface in the notation rack/slot/module/port for Node 1 and enters interface configuration mode.

Step 3 

srp ips request forced-switch {a | b}

Example:

RP/0/RP0/CPU0:router1(config-if)# srp ips request forced-switch a

(Optional) Adds a high-priority protection switch wrap on each end of the specified span. This stops traffic flowing from Node 1 on the fiber that will be disconnected and creates a wrap next to Node 1 on Side A.

Note If you choose not to use the srp ips request forced-switch command, as soon as you perform Step 5, a signal failure is detected by Node 1 and Node 4, and they automatically insert two signal-fail wraps away from the failure between the nodes. We recommend that you use the srp ips request forced-switch command to minimize data loss.

Step 4 

end

or

commit

Example:

RP/0/RP0/CPU0:router1(config-if)# end

or

RP/0/RP0/CPU0:router1(config-if)# commit

Saves configuration changes.

When you issue the end command, the system prompts you to commit changes:

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? [cancel]:
 
        

Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.

Step 5 

Disconnect the fiber-optic cables connecting Node 1 to Node 4.

 

Step 6 

Connect the cables to add the new node while observing the receive (RX) and transmit (TX) cabling relationship.

See Figure 5.

Step 7 

interface srp instance

Example:

RP/0/RP0/CPU0:router1(config)# interface srp 0/1/0/0

Specifies the SRP interface in the notation rack/slot/module/port for Node 1 and enters interface configuration mode.

Step 8 

no srp ips request forced-switch {a | b}

Example:

RP/0/RP0/CPU0:router1(config-if)# no srp ips request forced-switch a

Removes the high-priority protection switch wrap on each end of the specified span. This allows traffic to flow again from Node 1. (See Figure 5.)

Note If you performed Step 3, then you must use the no srp ips request forced-switch command to remove the wraps. If you did not perform Step 3, the wraps are removed automatically when the WTR timer has expired.

Step 9 

end

or

commit

Example:

RP/0/RP0/CPU0:router1(config-if)# end

or

RP/0/RP0/CPU0:router1(config-if)# commit

Saves configuration changes.

When you issue the end command, the system prompts you to commit changes:

Uncommitted changes found, commit them before 
exiting(yes/no/cancel)? [cancel]:
 
        

Entering yes saves configuration changes to the running configuration file, exits the configuration session, and returns the router to EXEC mode.

Entering no exits the configuration session and returns the router to EXEC mode without committing the configuration changes.

Entering cancel leaves the router in the current configuration session without exiting or committing the configuration changes.

Use the commit command to save the configuration changes to the running configuration file and remain within the configuration session.

Step 10 

show srp ips

Example:

RP/0/RP0/CPU0:router5# show srp ips

Confirms that the wraps have disappeared and the new node is part of the ring. (See Figure 5.)

Step 11 

show srp errors

Example:

RP/0/RP0/CPU0:router5# show srp errors

Confirms that there are no problems with the new ring configuration. If there are failures, note the status on the LEDs to determine what the problem might be.

Figure 2 Four Routers on the SRP Ring

Figure 3 Adding a Router to an SRP Ring

Figure 4 SRP Ring Topology with Four Nodes

1

Cisco CRS-1

2

Cisco XR 12000 or 12000 Series Router


Figure 5 SRP Ring Topology with a Fifth Node Added to a Wrapped Ring

1

Cisco CRS-1

2

Cisco XR 12000 or 12000 Series Router


Configuration Examples for SRP Interfaces

This section provides the following configuration examples:

Configuring SRP: Example

Configuring Modular QoS with SRP: Example

Configuring SRP: Example

This example shows how to configure SRP. First the ports are set to SRP mode using the hw-module port command, then the PLIM is reloaded, and then the basic interface configuration is performed.

RP/0/RP0/CPU0:router# configure 
RP/0/RP0/CPU0:router(config)# hw-module port 0 srp location 0/3/CPU0
RP/0/RP0/CPU0:router(config)# hw-module port 1 srp location 0/3/CPU0
RP/0/RP0/CPU0:router(config)# controller SONET 0/3/0/0 clock source internal
RP/0/RP0/CPU0:router(config)# controller SONET 0/3/0/1 clock source internal
RP/0/RP0/CPU0:router(config)# commit
RP/0/RP0/CPU0:router(config)# end
RP/0/RP0/CPU0:router# hw-module node 0/3/CPU0 reload
 
<Wait for LC to be reloaded, and interface created.  Or can use 'preconfigure'...>
 
RP/0/RP0/CPU0:router# configure 
RP/0/RP0/CPU0:router(config)# interface SRP 0/3/0/0
RP/0/RP0/CPU0:router(config-if)# ipv4 address 172.18.189.38 255.255.255.224
RP/0/RP0/CPU0:router(config-if)# no shutdown
RP/0/RP0/CPU0:router(config-if)# commit
RP/0/RP0/CPU0:router(config)# end
 
   

Configuring Modular QoS with SRP: Example

This example shows how to configure two quality-of-service (QoS) classes. One is for voice traffic and is identified by an MPLS experimental bit value of 4; the second is control traffic that is identified by an IP precedence value of 6. Both classes of traffic are sent to the SRP high priority queue and are marked with high SRP priority (4 and 6).

Last configuration change at 04:56:06 UTC Tue Sep 06 2005 by lab
!
hostname router
class-map match-any ctrl
 match precedence internet
!
class-map match-any voice
 match mpls experimental topmost 4
!
policy-map srp-policy
 class voice
  police cir 2000000
  set cos 4
  priority
 !
 class ctrl
  priority
  set cos 6
 !
!
interface SRP0/7/0/0
 description "Connected to 3-nodes ring"
 service-policy output srp-policy
 ipv4 address 30.30.30.2 255.255.255.0
 
   

Additional References

The following sections provide references related to SRP interface configuration.

Related Documents

Related Topic
Document Title

Cisco IOS XR master command reference

Cisco IOS XR Master Commands List

Cisco IOS XR interface configuration commands

Cisco IOS XR Interface and Hardware Component Command Reference

Initial system bootup and configuration information for a router using the Cisco IOS XR software

Cisco IOS XR Getting Started Guide

Cisco IOS XR AAA services configuration information

Cisco IOS XR System Security Configuration Guide and
Cisco IOS XR System Security Command Reference

Information about user groups and task IDs

Cisco IOS XR Task ID Reference Guide

Information about configuring interfaces and other components on the Cisco CRS-1 from a remote Craft Works Interface (CWI) client management application

Cisco CRS-1 Series Carrier Routing System Craft Works Interface Configuration Guide


Standards

Standards
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.


MIBs

MIBs
MIBs Link

To locate and download MIBs using Cisco IOS XR software, use the Cisco MIB Locator found at the following URL and choose a platform under the Cisco Access Products menu: http://cisco.com/public/sw-center/netmgmt/cmtk/mibs.shtml


RFCs

RFCs
Title

RFC-2892

The Cisco SRP MAC Layer Protocol


Technical Assistance

Description
Link

The Cisco Technical Support website contains thousands of pages of searchable technical content, including links to products, technologies, solutions, technical tips, and tools. Registered Cisco.com users can log in from this page to access even more content.

http://www.cisco.com/techsupport