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MPLS Traffic Engineering—RSVP Graceful Restart

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MPLS Traffic Engineering—RSVP Graceful Restart

Table Of Contents

MPLS Traffic Engineering—RSVP Graceful Restart

Contents

Prerequisites for MPLS TE—RSVP Graceful Restart

Restrictions for MPLS TE—RSVP Graceful Restart

Information About MPLS TE—RSVP Graceful Restart

Graceful Restart

Benefits

How to Configure MPLS TE—RSVP Graceful Restart

Enabling Graceful Restart

Setting a DSCP Value

Setting a Hello Refresh Interval

Setting a Missed Refresh Limit

Verifying Graceful Restart Configuration

Configuration Examples for MPLS TE—RSVP Graceful Restart

MPLS TE—RSVP Graceful Restart: Example

Additional References

Related Documents

Standards

MIBs

RFCs

Technical Assistance

Command Reference

ip rsvp signalling hello graceful-restart dscp

ip rsvp signalling hello graceful-restart mode help-neighbor

ip rsvp signalling hello graceful-restart refresh interval

ip rsvp signalling hello graceful-restart refresh misses

show ip rsvp counters

show ip rsvp counters state teardown

show ip rsvp hello

show ip rsvp hello client lsp detail

show ip rsvp hello client lsp summary

show ip rsvp hello client neighbor detail

show ip rsvp hello client neighbor summary

show ip rsvp hello graceful-restart

show ip rsvp hello instance detail

show ip rsvp hello instance summary

Glossary


MPLS Traffic Engineering—RSVP Graceful Restart


The Multiprotocol Label Switching (MPLS) Traffic Engineering (TE)—Resource Reservation Protocol (RSVP) Graceful Restart feature allows a neighboring route processor (RP) to recover from disruption in control plane service (specifically, the Label Distribution Protocol (LDP) component) without losing its MPLS forwarding state.

Feature History for MPLS TE—RSVP Graceful Restart

Release
Modification

12.0(29)S

This feature was introduced.


Finding Support Information for Platforms and Cisco IOS Software Images

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Contents

Prerequisites for MPLS TE—RSVP Graceful Restart

Restrictions for MPLS TE—RSVP Graceful Restart

Information About MPLS TE—RSVP Graceful Restart

How to Configure MPLS TE—RSVP Graceful Restart

Configuration Examples for MPLS TE—RSVP Graceful Restart

Additional References

Command Reference

Glossary

Prerequisites for MPLS TE—RSVP Graceful Restart

Configure RSVP on routers.

Enable MPLS.

Configure TE on routers.

Enable graceful restart.

Restrictions for MPLS TE—RSVP Graceful Restart

Graceful restart supports node failure only.

Graceful restart does not support restart or recovery on Cisco nodes, but helps in recovering a neighbor that is restart capable. Cisco routers advertise a restart time of 5 milliseconds and a recovery time of 0 in hello messages.

Unnumbered interfaces are not supported.

Information About MPLS TE—RSVP Graceful Restart

To configure MPLS TE—RSVP Graceful Restart, you need to understand the following concepts:

Graceful Restart

Benefits

Graceful Restart

Graceful restart allows RSVP TE enabled nodes to start gracefully following a node failure in the network such that the RSVP state after the failure is restored as quickly as possible. The node failure may be completely transparent to other nodes in the network as far as the RSVP state is concerned.

Graceful restart preserves the label values and forwarding information and works with third-party or Cisco routers seamlessly.

Graceful restart depends on RSVP hello messages that include Hello Request or Hello Acknowledgment (ACK) objects between two neighbors.

As shown in Figure 1, the graceful restart extension to these messages adds an object called Restart_Cap, which tells neighbors that a node may be capable of restarting if a failure occurs. The TTL in these messages is set to 255 so that adjacencies can be maintained through alternate paths even if the link between two neighbors goes down.

Figure 1 How Graceful Restart Works

The Restart_Cap object has two values—the restart time, which is the sender's time to restart the RSVP_TE component and exchange hello messages after a failure; and the recovery time, which is the desired time that the sender wants the receiver to synchronize the RSVP/MPLS databases.

In Figure 1, graceful restart is enabled on Router 1, Router 2, Router 3, and Router 4. For simplicity, assume that all routers are restart capable. A TE label-switched path (LSP) is signaled from Router 1 to Router 4.

Router 2 and Router 3 exchange periodic graceful restart hello messages every 10000 milliseconds (10 seconds), and so do Router 2 and Router 1 and Router 3 and Router 4. Assume that Router 2 advertises its restart time = 60000 milliseconds (60 seconds) and its recovery time = 60000 milliseconds (60 seconds) as shown below:

23:33:36: Outgoing Hello:
23:33:36:   version:1 flags:0000 cksum:883C ttl:255 reserved:0 length:32
23:33:36:  HELLO                type HELLO REQUEST length 12:
23:33:36:   Src_Instance: 0x6EDA8BD7, Dst_Instance: 0x00000000
23:33:36:  RESTART_CAP          type 1 length 12:
23:33:36:   Restart_Time: 0x0000EA60, Recovery_Time: 0x0000EA60

Router 3 records this into its database. Also, both neighbors maintain the neighbor status as UP. However, Router 3's control plane fails at some point (for example, a Primary Route Processor failure). As a result, RSVP and TE lose their signaling information/states although data packets are kept forwarded by the line cards.

When four ACK messages are missed from Router 2 (40 seconds), Router 3 declares communication with Router 2 lost indicated by LOST and starts the restart time to wait for the duration advertised in Router 2's restart time previously and recorded (60 seconds). Router 1 and Router 2 suppress all RSVP messages to Router 3 except hellos. Router 3 keeps sending the RSVP Path and Resv refresh messages to Router 4 and Router 5 so that they do not expire the state for the LSP; however, Router 3 suppresses these messages for Router 2.


Note A node is restarting if it misses four ACKs or its hello src_instance (last source instance sent to its neighbor) changes so that its restart time = 0.


Before the restart time expires, Router 2 restarts and loads its configuration and graceful restart makes it send the hello messages with a new source instance to all the datalinks attached. However, since Router 2 has lost the neighbor states, it does not know what destination instance it should use in those messages; therefore, all destination instances are set to 0.

When Router 3 sees the hello from Router 2, Router 3 stops the restart time for Router 2 and sends an ACK message back. When Router 3 sees a new source instance value in Router 2's hello message, Router 3 knows that Router 2 had a control plane failure. Router 2 gets Router 3's source instance value and uses it as the destination instance going forward.

Router 3 also checks the recovery time value in the hello message from Router 2. If the recovery time is 0, Router 3 knows that Router 2 was not able to preserve its forwarding information and Router 3 deletes all RSVP state that it had with Router 2.

If the recovery time is greater than 0, Router 1 sends Router 2 Path messages for each LSP that it had previously sent through Router 2. If these messages were previously refreshed in summary messages, they are sent individually during the recovery time. Each of these Path messages includes a Recovery_Label object containing the label value received from Router 2 before the failure.

When Router 3 receives a Path message from Router 2, Router 3 sends a Resv message upstream. However, Router 3 suppresses the Resv message until it receives a Path message.

Benefits

State Information Recovery

Graceful restart allows a node to recover state information from its neighbor when there is a route processor (RP) failure or the device has undergone a stateful switchover (SSO).

Session Information Recovery

Graceful restart allows session information recovery with minimal disruption to the network.

Increased Availability of Network Services

A node can perform a graceful restart to help a neighbor recover its state by keeping the label bindings and state information thereby providing a faster recovery of the failed node and not affecting currently forwarded traffic.

How to Configure MPLS TE—RSVP Graceful Restart

This section contains the following procedures:

Enabling Graceful Restart (required)

Setting a DSCP Value (optional)

Setting a Hello Refresh Interval (optional)

Setting a Missed Refresh Limit (optional)

Verifying Graceful Restart Configuration (optional)

Enabling Graceful Restart

Perform this task to enable graceful restart.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip rsvp signalling hello graceful-restart mode help-neighbor

4. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip rsvp signalling hello graceful-restart mode help-neighbor

Example:

Router(config)# ip rsvp signalling hello graceful-restart mode help-neighbor

Enables graceful restart on a neighboring router with restart capability.

Step 4 

end

Example:

Router(config)# end

Exits to privileged EXEC mode.

Setting a DSCP Value

Perform this task to set a DSCP value.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip rsvp signalling hello graceful-restart dscp num

4. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip rsvp signalling hello graceful-restart dscp num

Example:

Router(config)# ip rsvp signalling hello graceful-restart dscp 30

Sets a DSCP value on a router with graceful restart enabled.

Step 4 

end

Example:

Router(config)# end

Exits to privileged EXEC mode.

Setting a Hello Refresh Interval

Perform this task to set a hello refresh interval.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip rsvp signalling hello graceful-restart refresh interval interval-value

4. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip rsvp signalling hello graceful-restart refresh interval interval-value

Example:

Router(config)# ip rsvp signalling hello graceful-restart refresh interval 5000

Sets a hello refresh interval on a router with graceful restart enabled.

Step 4 

end

Example:

Router(config)# end

Exits to privileged EXEC mode.

Setting a Missed Refresh Limit

Perform this task to set a missed refresh limit.

SUMMARY STEPS

1. enable

2. configure terminal

3. ip rsvp signalling hello graceful-restart refresh misses msg-count

4. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

configure terminal

Example:

Router# configure terminal

Enters global configuration mode.

Step 3 

ip rsvp signalling hello graceful-restart refresh misses msg-count

Example:

Router(config)# ip rsvp signalling hello graceful-restart refresh misses 5

Sets a refresh limit on a router with graceful restart enabled.

Step 4 

end

Example:

Router(config)# end

Exits to privileged EXEC mode.

Verifying Graceful Restart Configuration

Perform this task to verify graceful restart configuration.

SUMMARY STEPS

1. enable

2. show ip rsvp hello graceful-restart

3. end

DETAILED STEPS

 
Command or Action
Purpose

Step 1 

enable

Example:

Router> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2 

show ip rsvp hello graceful-restart

Example:

Router# show ip rsvp hello graceful-restart

Displays information about the status of graceful restart and related parameters.

Step 3 

end

Example:

Router# end

Exits to user EXEC mode.

Configuration Examples for MPLS TE—RSVP Graceful Restart

This section provides a configuration example for the MPLS TE—RSVP Graceful Restart feature.

MPLS TE—RSVP Graceful Restart: Example

MPLS TE—RSVP Graceful Restart: Example

In the following example, graceful restart is enabled, and related parameters, including a DSCP value, a refresh interval, and a missed refresh limit are set.

Router# configure terminal

Enter configuration commands, one per line.  End with CNTL/Z.

Router(config)# ip rsvp signalling hello graceful-restart mode help-neighbor

Router(config)# ip rsvp signalling hello graceful-restart dscp 30

Router(config)# ip rsvp signalling hello graceful-restart refresh interval 10000

Router(config)# ip rsvp signalling hello graceful-restart refresh misses 4

Router(config)# end

The following example verifies the status of graceful restart and the configured parameters:

Router# show ip rsvp hello graceful-restart

Graceful Restart:Enabled (help-neighbor only)
  Refresh interval:10000 msecs
  Refresh misses:4
  DSCP:0x30
  Advertised restart time:0 secs
  Advertised recovery time:0 secs
  Maximum wait for recovery:3600000 secs


Additional References

The following sections provide references related to the MPLS TE—RSVP Graceful Restart feature.

Related Documents

Related Topic
Document Title

RSVP commands: complete command syntax, command mode, defaults, usage guidelines, and examples

Cisco IOS Quality of Service Solutions Command Reference, Release 12.3 T

QoS features including signaling, classification, and congestion management

Cisco IOS Quality of Service Solutions Configuration Guide, Release 12.3

Stateful Switchover

Stateful Switchover feature module

MPLS Label Distribution Protocol

MPLS Label Distribution Protocol (LDP) feature module

Cisco Nonstop Forwarding

Cisco Nonstop Forwarding feature module

Information on Stateful Switchover, Cisco Nonstop Forwarding, graceful restart

MPLS LDP: SSO/NSF Support and Graceful Restart feature module

Hellos for state timeout

MPLS TE—RSVP Hello State Timer feature module


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

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

To locate and download MIBs for selected platforms, Cisco IOS releases, and feature sets, use Cisco MIB Locator found at the following URL:

http://www.cisco.com/go/mibs


RFCs

RFCs
Title

RFC 3209

RSVP-TE: Extensions to RSVP for LSP Tunnels

RFC 3473

Generalized Multi-Protocol Label Switching (GMPLS) Signaling Resource Reservation Protocol-Traffic Engineering (RSVP-TE) Extensions

RFC 3478

Graceful Restart Mechanism for Label Distribution


Technical Assistance

Description
Link

Technical Assistance Center (TAC) home page, containing 30,000 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/public/support/tac/home.shtml


Command Reference

This section documents new and modified commands. All other commands used with this feature are documented in the Cisco IOS Release 12.3 command reference publications.

New Commands

ip rsvp signalling hello graceful-restart dscp

ip rsvp signalling hello graceful-restart mode help-neighbor

ip rsvp signalling hello graceful-restart refresh interval

ip rsvp signalling hello graceful-restart refresh misses

show ip rsvp counters state teardown

show ip rsvp hello client lsp detail

show ip rsvp hello client lsp summary

show ip rsvp hello client neighbor detail

show ip rsvp hello client neighbor summary

show ip rsvp hello graceful-restart

Modified Commands

show ip rsvp counters

show ip rsvp hello

show ip rsvp hello instance detail

show ip rsvp hello instance summary

ip rsvp signalling hello graceful-restart dscp

To set the differentiated services code point (DSCP) value that is in the IP header of a Resource Reservation Protocol (RSVP) Traffic Engineering (TE) graceful restart hello message, use the ip rsvp signalling hello graceful-restart dscp command in global configuration mode. To set the DSCP to its default value, use the no form of this command.

ip rsvp signalling hello graceful-restart dscp num

no ip rsvp signalling hello graceful-restart dscp

Syntax Description

num

DSCP value. Valid values are from 0 to 63.


Defaults

The default value is 48.

Command Modes

Global configuration

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

If a link is congested, set the DSCP to a value higher than 0 to reduce the likelihood that hello messages will be dropped.

The DSCP applies to all RSVP hellos created on a specific router. You can configure each router independently for the DSCP.

Examples

In the following example, hello messages have a DSCP value of 30:

Router(config)# ip rsvp signalling hello graceful-restart dscp 30

Related Commands

Command
Description

ip rsvp signalling hello graceful-restart refresh interval

Sets the hello request interval in graceful restart hello messages.

ip rsvp signalling hello graceful-restart refresh misses

Sets the missed refresh limit in graceful restart hello messages.


ip rsvp signalling hello graceful-restart mode help-neighbor

To enable Resource Reservation Protocol (RSVP) Traffic Engineering (TE) graceful restart capability on a neighboring router, use the ip rsvp signalling hello graceful-restart mode help-neighbor command in global configuration mode. To disable graceful restart capability, use the no form of this command.

ip rsvp signalling hello graceful-restart mode help-neighbor

no ip rsvp signalling hello graceful-restart mode help-neighbor

Syntax Description

This command has no arguments or keywords.

Defaults

Graceful restart is disabled.

Command Modes

Global configuration

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the ip rsvp signalling hello graceful-restart mode help-neighbor command to restart a neighboring router.

Examples

In the following example, graceful restart is enabled:

Router(config)# ip rsvp signalling hello graceful-restart mode help-neighbor

Related Commands

Command
Description

ip rsvp signalling hello graceful-restart dscp

Sets the DSCP value in graceful restart hello messages.

ip rsvp signalling hello graceful-restart refresh interval

Sets the hello request interval in graceful restart hello messages.

ip rsvp signalling hello graceful-restart refresh misses

Sets the missed refresh limit in graceful restart hello messages.


ip rsvp signalling hello graceful-restart refresh interval

To configure the Resource Reservation Protocol (RSVP) Traffic Engineering (TE) graceful restart hello request interval, use the ip rsvp signalling hello grateful-restart refresh interval command in global configuration mode. To set the interval to its default value, use the no form of this command.

ip rsvp signalling hello graceful-restart refresh interval interval-value

no ip rsvp signalling hello graceful-restart refresh interval

Syntax Description

interval-value

Frequency, in milliseconds, at which a node sends hello messages to a neighbor. Valid values are from 1000 to 30000.


Defaults

10000 milliseconds (10 seconds)

Command Modes

Global configuration

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

A node periodically generates a hello message containing a Hello Request object for all its neighbors. The frequency of those hello messages is determined by the hello interval.

Examples

In the following example, hello requests are sent to a neighbor every 5000 milliseconds:

Router(config)# ip rsvp signalling hello graceful-restart refresh interval 5000

Related Commands

Command
Description

ip rsvp signalling hello graceful-restart dscp

Sets the DSCP value in graceful restart hello messages.

ip rsvp signalling hello graceful-restart refresh misses

Sets the missed refresh limit in graceful restart hello messages.


ip rsvp signalling hello graceful-restart refresh misses

To specify how many sequential Resource Reservation Protocol (RSVP) Traffic Engineering (TE) graceful restart hello acknowledgments (ACKs) a node can miss before the node considers communication with its neighbor lost, use the ip rsvp signalling hello graceful-restart refresh misses command in global configuration mode. To return the missed refresh limit to its default value, use the no form of the command.

ip rsvp signalling hello graceful-restart refresh misses msg-count

no ip rsvp signalling hello graceful-restart refresh misses

Syntax Description

msg-count

The number of sequential hello acknowledgments (ACKs) that a node can miss before RSVP considers the state expired and tears it down. Valid values are from 4 to 10.


Defaults

The default is 4.

Command Modes

Global configuration

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

A hello messages comprises a hello message, a Hello Request object, and a Hello ACK object. Each request is answered by an acknowledgment. If a link is very congested or a router has a very heavy load, set this number to a value higher than the default value to ensure that hello does not falsely declare that a neighbor is down.

Examples

In the following example, if the node does not receive five sequential hello acknowledgments, the node declares that its neighbor is down:

Router(config)# ip rsvp signalling hello graceful-restart refresh misses 5

Related Commands

Command
Description

ip rsvp signalling hello graceful-restart dscp

Sets the DSCP value in graceful restart hello messages.

ip rsvp signalling hello graceful-restart refresh interval

Sets the request interval in graceful restart hello messages.


show ip rsvp counters

To display the number of Resource Reservation Protocol (RSVP) messages that were sent and received on each interface, use the show ip rsvp counters command in privileged EXEC mode.

show ip rsvp counters [authentication | interface interface_unit | neighbor | summary]

Syntax Description

authentication

(Optional) List of RSVP authentication counters.

interface interface_unit

(Optional) Number of RSVP messages sent and received for the specified interface name.

neighbor

(Optional) Number of RSVP messages sent and received by the specified neighbor.

summary

(Optional) Cumulative number of RSVP messages sent and received by the router over all interfaces.


Defaults

If you enter the show ip rsvp counters command without a keyword, the command displays the number of RSVP messages that were sent and received for each interface on which RSVP is configured.

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(14)ST

This command was introduced.

12.2(13)T

The neighbor keyword was added, and the command was integrated into Cisco IOS Release 12.2(13)T.

12.2(15)T

The output was modified to show the errors counter incrementing whenever an RSVP message is received on an interface with RSVP authentication enabled, but the authentication checks failed on that message.

12.0(24)S

This command was integrated into Cisco IOS Release 12.0(24)S.

12.0(29)S

The optional authentication keyword was added and the command output was modified to include hello and message queues information.


Examples

The following command shows the values for the number of RSVP messages of each type that were sent and received by the router over all interfaces including the hello and message queues information:

Router# show ip rsvp counters summary

All Interfaces          Recv      Xmit                        Recv      Xmit
    Path                  110        15    Resv                   50        28
    PathError               0         0    ResvError               0         0
    PathTear                0         0    ResvTear                0         0
    ResvConf                0         0    RTearConf               0         0
    Ack                     0         0    Srefresh                0         0
    Hello                5555      5554    IntegrityChalle         0         0
    IntegrityRespon         0         0    DSBM_WILLING            0         0
    I_AM_DSBM               0         0
    Unknown                 0         0    Errors                  0         0

Recv Msg Queues                Current       Max
    RSVP                             0         2
    Hello (per-I/F)                  0         1
    Awaiting Authentication          0         0

Table 1 describes the significant fields shown in the display.

Table 1 show ip rsvp counters summary Field Descriptions 

Field
Description

All Interfaces

Types of messages displayed for all interfaces.

Note Hello is a summary of graceful restart, reroute (hello state timer), and Fast Reroute messages.

Recv

Number of messages received on the specified interface or on all interfaces.

Xmit

Number of messages transmitted from the specified interface or from all interfaces.

Recv Msg Queues

Queues for received messages for RSVP, hello per interface, and awaiting authentication. Current = number of messages presently queued. Max = maximum number of messages ever queued.


Related Commands

Command
Description

clear ip rsvp counters

Clears (sets to zero) all IP RSVP counters that are being maintained.


show ip rsvp counters state teardown

To display counters for Resource Reservation Protocol (RSVP) events that caused a state to be torn down, use the show ip rsvp counters state teardown command in privileged EXEC mode.

show ip rsvp counters state teardown

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the show ip rsvp counters state teardown command when a label-switched path (LSP) is down. If graceful restart triggered the state teardown, the numbers in the Path, Resv-In, and Resv-Out columns in the display below are greater than 0.

Examples

The following is sample output from the show ip rsvp counters state teardown command:

Router# show ip rsvp counters state teardown

States
  Reason for Teardown                          State torn down
                                                 Path    Resv-In   Resv-Out
  PathTear arrival                                  0          0          0
  ResvTear arrival                                  0          0          0
  Local application requested tear                  0          0          0
  Output or Input I/F went down                     0          0          0
  Missed refreshes                                  0          0          0
  Preemption                                        0          0          0
  Backup tunnel failed for FRR Active LSP           0          0          0
  Reroutabilty changed for FRR Active LSP           0          0          0
  Hello RR Client (HST) requested tear              0          0          0
  Graceful Restart (GR) requested tear              0          0          0 <-----GR
  Downstream neighbor SSO-restarting                0          0          0
  Resource unavailable                              0          0          0
  Policy rejection                                  0          0          0
  Policy server sync failed                         0          0          0
  Traffic control error                             0          0          0
  Error in received message                         0          0          0
  Non RSVP HOP upstream, TE LSP                     0          0          0
  Other                                             0          0          0


Table 2 describes the significant fields shown in the display.

Table 2 show ip rsvp counters state teardown Field Descriptions 

Field
Description

States

RSVP state including path state block (PSB) and reservation state block (RSB) information.

Reason for Teardown

Event triggering the teardown.


Related Commands

Command
Description

clear ip rsvp counters

Clears (sets to zero) all IP RSVP counters that are being maintained.


show ip rsvp hello

To display the status of Resource Reservation Protocol (RSVP) Traffic Engineering (TE) hellos and statistics, use the show ip rsvp hello command in privileged EXEC mode.

show ip rsvp hello

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(22)S

This command was introduced.

12.0(29)S

The command output was modified to include graceful restart, reroute (hello state timer), and Fast Reroute information.


Usage Guidelines

Use the show ip rsvp hello command to check the status (enabled or disabled) of graceful restart.

Examples

The following is sample output from the show ip rsvp hello command:

Router# show ip rsvp hello

Hello:
  Fast-Reroute/Reroute:Enabled
    Statistics:Enabled
  Graceful Restart:Enabled (help-neighbor only)

Table 3 describes the significant fields shown in the display.

Table 3 show ip rsvp hello Field Descriptions 

Field
Description

Hello

Subsequent fields describe the processes for which hello is enabled. Choices include Fast Reroute, reroute (hello for state timer), and graceful restart for a neighbor with restart capability.

Statistics

Status of hello statistics. Valid values are as follows:

Enabled—Statistics are configured. Hello packets are time-stamped when they arrive in the hello input queue for the purpose of recording the time it takes until they are processed.

Disabled—Hello statistics are not configured.

Shutdown—Hello statistics are configured but not operational. The input queue is too long (that is, more than 10,000 packets are queued).


Related Commands

Command
Description

show ip rsvp hello statistics

Shows how long hello packets have been in the hello input queue.


show ip rsvp hello client lsp detail

To display detailed information about Resource Reservation Protocol (RSVP) Traffic Engineering (TE) client hellos for label-switched paths (LSPs), use the show ip rsvp hello client lsp detail command in privileged EXEC mode.

show ip rsvp hello client lsp detail

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the show ip rsvp hello client lsp detail command to display information about the LSPs including IP addresses and their types.

Examples

The following is sample output from the show ip rsvp hello client lsp detail command:

Router# show ip rsvp hello client lsp detail

Hello Client LSPs (all lsp tree)

  Tun Dest:   88.1.1.1  Tun ID: 14  Ext Tun ID: 55.1.1.1
  Tun Sender: 55.1.1.1  LSP ID: 31
    Lsp flags: 0x32
    Lsp GR DN nbr: 99.1.1.1
    Lsp RR DN nbr: 15.0.0.3 HST

Table 4 describes the significant fields shown in the display.

Table 4 show ip rsvp hello client lsp detail Field Descriptions 

Field
Description

Hello Client LSPs

Subsequent fields provide information that uniquely identifies the LSP. Current clients include graceful restart (GR), reroute (RR) (hello state timer), and Fast Reroute (FRR).

Tun Dest

IP address of the destination tunnel.

Tun ID

Identification number of the tunnel.

Ext Tun ID

Extended identification number of the tunnel. Usually, this is the same as the source address.

Tun Sender

IP address of the tunnel sender.

LSP ID

Identification number of the LSP.

Lsp Flags

LSP database information.

Lsp GR DN nbr

IP address of the LSP graceful restart downstream neighbor.

Lsp RR DN nbr

IP address LSP reroute downstream neighbor; HST = hello state timer.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.


show ip rsvp hello client lsp summary

To display summary information about Resource Reservation Protocol (RSVP) Traffic Engineering (TE) client hellos for label-switched paths (LSPs), use the show ip rsvp hello client lsp summary command in privileged EXEC mode.

show ip rsvp hello client lsp summary

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the show ip rsvp hello client lsp summary command to display information about the LSPs including IP addresses and identification numbers.

Examples

The following is sample output from the show ip rsvp hello client lsp summary command:

Router# show ip rsvp hello client lsp summary

Local           Remote          tun_id  lsp_id  FLAGS       
55.1.1.1        88.1.1.1        14      31      0x32

Table 5 describes the significant fields shown in the display.

Table 5 show ip rsvp hello client lsp summary Field Descriptions 

Field
Description

Local

IP address of the tunnel sender.

Remote

IP address of thetunnel destination.

tun id

Identification number of the tunnel.

lsp id

Identification number of the LSP.

Flags

Database information.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.


show ip rsvp hello client neighbor detail

To display detailed information about Resource Reservation Protocol (RSVP) Traffic Engineering (TE) client hellos for neighbors, use the show ip rsvp hello client neighbor detail command in privileged EXEC mode.

show ip rsvp hello client neighbor detail

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the show ip rsvp hello client neighbor detail command to display information about the hello neighbors including their state and type.

Examples

The following is sample output from the show ip rsvp hello client neighbor detail command:

Router# show ip rsvp hello client neighbor detail

Hello Client Neighbors

  Remote addr 15.0.0.1,  Local addr  15.0.0.3
    Nbr State: Normal    Type: Reroute
    Nbr Hello State: Up
    LSPs protecting: 1
    I/F: Et1/3

  Remote addr 55.1.1.1,  Local addr  99.1.1.1
    Nbr State: Normal    Type: Graceful Restart
    Nbr Hello State: Lost
    LSPs protecting: 1

Table 6 describes the significant fields shown in the display.

Table 6 show ip rsvp hello client neighbor detail Field Descriptions 

Field
Description

Hello Client Neighbors

Subsequent fields provide information that uniquely identifies the neighbors. Clients can include graceful restart, reroute (hello state timer), and Fast Reroute.

Remote addr

IP address of the remote neighbor. For graceful restart, this is the neighbor router's ID; for Fast Reroute and hello state timer (reroute), this is one of the neighbor's interface addresses.

Local addr

IP address of the local neighbor. For graceful restart, this is the neighbor router's ID; for Fast Reroute and hello state timer (reroute), this is one of the neighbor's interface addresses.

Nbr State

State of the neighbor; values can be the following:

Normal = neighbor is functioning normally.

Restarting = neighbor is restarting.

Recover Nodal = neighbor is recovering from node failure.

HST_GR_LOST = HST (hello state timer for reroute) is lost; waiting to see if GR (graceful restart) is also lost.

WAIT PathTear = PathTear message is delayed to allow traffic in the pipeline to be transmitted.

Type

Type of client; graceful restart, reroute (hello state timer), or Fast Reroute.

Nbr Hello State

State of hellos for the neighbor. Values are Up (node is communicating with its neighbor) and Lost (communication has been lost or never was established).

Lsps protecting

Number of LSPs being protected.

I/F

Interface name and number associated with the hello instance.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.


show ip rsvp hello client neighbor summary

To display summary information about Resource Reservation Protocol (RSVP) Traffic Engineering (TE) client hellos for neighbors, use the show ip rsvp hello client neighbor summary command in privileged EXEC mode.

show ip rsvp hello client neighbor summary

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the show ip rsvp hello client neighbor summary command to display information about the neighbors including state, type, and hello instance status.

Examples

The following is sample output from the show ip rsvp hello client neighbor summary command:

Router# show ip rsvp hello client neighbor summary

Local           Remote          Type    NBR_STATE    HI_STATE    LSPs
15.0.0.1        15.0.0.3        RR      Normal       Up             1
55.1.1.1        99.1.1.1        GR      Normal       Lost           1

Table 7 describes the significant fields shown in the display.

Table 7 show ip rsvp hello client neighbor summary Field Descriptions 

Field
Description

Local

IP address of the tunnel sender.

Remote

IP address of the tunnel destination.

Type

Type of client; graceful restart (GR), reroute (RR (hello state timer)), or Fast Reroute (FRR).

NBR_STATE

State of the neighbor; values can be the following:

Normal = neighbor is functioning normally.

Restarting = neighbor is restarting.

Recover Nodal = neighbor is recovering from node failure.

HST_GR_LOST = HST (hello state timer for reroute) is lost; waiting to see if GR (graceful restart) is also lost.

WAIT PathTear = PathTear message is delayed to allow traffic in the pipeline to be transmitted.

HI_STATE

State of hello instances for the neighbor. Values are Up (node is communicating with its neighbor) and Lost (communication has been lost or never was established).

LSPs

Number of LSPs going to or coming from the neighbor.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.


show ip rsvp hello graceful-restart

To display information about Resource Reservation Protocol (RSVP) Traffic Engineering (TE) graceful restart hellos, use the show ip rsvp hello graceful-restart command in privileged EXEC mode.

show ip rsvp hello graceful-restart

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(29)S

This command was introduced.


Usage Guidelines

Use the show ip rsvp hello graceful-restart command to display the status of graceful restart and related statistics for a neighbor node with restart capability.

Examples

The following is sample output from the show ip rsvp hello graceful-restart command:

Router# show ip rsvp hello graceful-restart

Graceful Restart: Enabled (help-neighbor only)
  Refresh interval: 10000 msecs
  Refresh misses: 4
  DSCP: 0x30
  Advertised restart time: 5 msecs
  Advertised recovery time: 0 msecs
  Maximum wait for recovery: 3600000 msecs

Table 8 describes the significant fields shown in the display.

Table 8 show ip rsvp hello graceful-restart Field Descriptions 

Field
Description

Graceful Restart

Enabled = on for a neighboring router that is restart capable. Disabled = off.

Refresh interval

Frequency in milliseconds (msec) with which a node sends a hello message to its neighbor.

Refresh misses

Number of sequential acknowledgments that a node did not receive.

DSCP

The differentiated services code point (DSCP) value in hello messages.

Advertised restart time

The time, in milliseconds (msec) that it takes the sender to restart the RSVP_TE component and exchange hello messages after a failure.

Advertised recovery time

The desired time, in milliseconds (msec), that the sender wants the receiver to synchronize the RSVP/MPLS databases after a failure.

Maximum wait for recovery

The maximum amount of time, in milliseconds (msec), that the router waits for a neighbor to recover.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.


show ip rsvp hello instance detail

To display detailed information about a Resource Reservation Protocol (RSVP) Traffic Engineering (TE) hello instance, use the show ip rsvp hello instance detail command in privileged EXEC mode.

show ip rsvp hello instance detail [filter destination ip-address]

Syntax Description

filter destination ip-address

(Optional) IP address of the neighbor node.


Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(22)S

This command was introduced.

12.0(29)S

The command output was modified to include graceful restart, hello state timer (reroute), and Fast Reroute information.


Usage Guidelines

Use the show ip rsvp hello instance detail command to display information about the processes (clients) currently configured.

Examples

The following is sample output from the show ip rsvp hello instance detail command:

Router# show ip rsvp hello instance detail

Neighbor 12.0.0.3  Source  12.0.0.2
    Type: Active    (sending requests)
    I/F:  Serial2/0
    State:   Up        (for 2d19h2d19h)
    Clients: ReRoute
    LSPs protecting: 1
    Missed acks: 4, IP DSCP: 0x30
    Refresh Interval (msec)
      Configured: 6000
      Statistics: (from 40722 samples)
        Min:      6000
        Max:      6064
        Average:  6000
        Waverage: 6000 (Weight = 0.8)
        Current:  6000
    Last sent Src_instance: 0xE617C847
    Last recv nbr's Src_instance: 0xFEC28E95
    Counters:
      Communication with neighbor lost:
        Num times:                    0
        Reasons:
          Missed acks:                0
          Bad Src_Inst received:      0
          Bad Dst_Inst received:      0
          I/F went down:              0
          Neighbor disabled Hello:    0
      Msgs Received:   55590
           Sent:       55854
           Suppressed: 521

  Neighbor 14.0.0.1  Source  14.0.0.2
    Type: Passive   (responding to requests)
    I/F:  Serial2/1
    Last sent Src_instance: 0xF7A80A52
    Last recv nbr's Src_instance: 0xD2F1B7F7
    Counters:
      Msgs Received:   199442
           Sent:       199442

Table 9 describes the significant fields shown in the display.

Table 9 show ip rsvp hello instance detail Field Descriptions 

Field
Description

Neighbor

IP address of the adjacent node.

Source

IP address of the node that is sending the hello message.

Type

Values are Active (node is sending a request) and Passive (node is responding to a request).

I/F

Interface from which hellos are sent for this instance. Any means that the hellos can be sent out any interface.

State

Status of communication. Values are Up (node is communicating with its neighbor and for how long) and Lost (communication has been lost or never was established).

Clients

Client(s) that created this hello instance; they include graceful restart, reroute (hello state timer), and Fast Reroute.

LSPs protecting

Number of LSPs that are being protected by this hello instance.

Missed acks

Number of times that communication was lost due to missed ACKs.

IP DSCP

IP DSCP value used in the hello IP header.

Refresh Interval (msec)

The frequency (in milliseconds) with which a node generates a hello message containing a Hello Request object for each neighbor whose status is being tracked.

Configured

Configured refresh interval.

Statistics

Refresh interval statistics from a specified number of samples (packets).

Min

Minimum refresh interval.

Max

Maximum refresh interval.

Average

Average refresh interval.

Waverage

Weighted average refresh interval.

Current

Current refresh interval.

Last sent Src_instance

The last source instance sent to a neighbor.

Last recv nbr's Src_instance

The last source instance field value received from a neighbor. (0 means none received.)

Counters

Incremental information relating to communication with a neighbor.

Communication with neighbor lost

Subsequent fields designate the number of times that communication with a neighbor was lost and why.

Num times

Total number of times that communication with a neighbor was lost.

Reasons

Subsequent fields designate why communication with a neighbor was lost.

Missed acks

Number of times that communication was lost due to missed ACKs.

Bad Src_Inst received

Number of times that communication was lost due to bad source instance fields.

Bad Dst_Inst received

Number of times that communication was lost due to bad destination instance fields.

I/F went down

Number of times that the interface became unoperational.

Neighbor disabled Hello

Number of times that a neighbor disabled hello messages.

Msgs Received

Number of messages that were received.

Sent

Number of messages that were sent.

Suppressed

Number of messages that were suppressed due to optimization.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.

show ip rsvp hello instance summary

Displays summary information about a hello instance.


show ip rsvp hello instance summary

To display summary information about a Resource Reservation Protocol (RSVP) Traffic Engineering (TE) hello instance, use the show ip rsvp hello instance summary command in privileged EXEC mode.

show ip rsvp hello instance summary

Syntax Description

This command has no arguments or keywords.

Defaults

No default behavior or values

Command Modes

Privileged EXEC

Command History

Release
Modification

12.0(22)S

This command was introduced.

12.0(29)S

The command output was modified to include graceful restart, reroute (hello state timer), and Fast Reroute information.


Usage Guidelines

Use the show ip rsvp hello instance summary command to see which nodes are sending hellos (active instances) and which nodes are responding to hellos (passive instances).

Examples

The following is sample output from the show ip rsvp hello instance summary command:

Router# show ip rsvp hello instance summary

Active Instances:
  Client  Neighbor        I/F        State      LostCnt  LSPs Interval
  RR      12.0.0.3        Se2/0      Up               0     1 6000    
  GR      55.1.1.1        Any        Up              13     1 10000   
  GR      99.1.1.1        Any        Lost             0     1 10000   

Passive Instances:
  Neighbor        I/F       
  14.0.0.1        Se2/1     

Active = Actively tracking neighbor state on behalf of clients:
         RR = ReRoute, FRR = Fast ReRoute, or GR = Graceful Restart
Passive = Responding to hello requests from neighbor

Table 10 describes the significant fields shown in the display.

Table 10 show ip rsvp hello instance summary Field Descriptions 

Field
Description

Active Instances

Subsequent fields describe the active nodes that are sending hello requests.

Client

Client(s) on behalf of which hellos are sent; they include GR (graceful restart), RR (reroute = hello state timer), and FRR (Fast Reroute).

Neighbor

IP address of adjacent node. For graceful restart, this is the neighbor router's ID; for Fast Reroute and hello state timer (reroute), this is one of the neighbor's interface addresses.

I/F

Interface from which hellos are sent for this instance. Any means that the hellos can be sent out any interface.

State

Status of communication. Values are Up (node is communicating with its neighbor) and Lost (communication has been lost or never was established).

LostCnt

Number of times that communication was lost with the neighbor.

LSPs

Number of label-switched paths (LSPs) protected by this hello instance.

Interval

Hello refresh interval in milliseconds

Passive Instances

Subsequent fields describe the passive nodes that are responding to hello requests.

Neighbor

IP address of adjacent node. For graceful restart, this is the neighbor router's ID; for Fast Reroute and hello state timer (reroute), this is one of the neighbor's interface addresses.

I/F

Interface from which hellos are sent for this instance. Any means that the hellos can be sent out any interface.


Related Commands

Command
Description

show ip rsvp hello

Displays hello status and statistics for Fast Reroute, reroute (hello state timer), and graceful restart.

show ip rsvp hello instance detail

Shows detailed information about a hello instance.


Glossary

AS—autonomous system. A collection of networks that share the same routing protocol and that are under the same system administration.

ASBR—autonomous system boundary router. A router that connects and exchanges information between two or more autonomous systems.

backup tunnel—An MPLS Traffic Engineering tunnel used to protect other (primary) tunnels' traffic when a link or node failure occurs.

DSCP—Differentiated Services Code Point. Six bits in the IP header, as defined by the IETF. These bits determine the class of service provided to the IP packet.

Fast Reroute—A mechanism for protecting MPLS Traffic Engineering (TE) LSPs from link and node failure by locally repairing the LSPs at the point of failure, allowing data to continue to flow on them while their headend routers attempt to establish end-to-end LSPs to replace them. FRR locally repairs the protected LSPs by rerouting them over backup tunnels that bypass failed links or nodes.

graceful restart—A process for helping a neighboring route processor restart after a node failure has occurred.

headend—The router that originates and maintains a given LSP. This is the first router in the LSP's path.

IGP—Interior Gateway Protocol. Internet protocol used to exchange routing information within an autonomous system. Examples of common Internet IGPs include IGRP, OSPF, and RIP.

instance—A mechanism that implements the RSVP hello extensions for a given router interface address and remote IP address. Active hello instances periodically send Hello Request messages, expecting Hello ACK messages in response. If the expected ACK message is not received, the active hello instance declares that the neighbor (remote IP address) is unreachable (that is, it is lost). This can cause LSPs crossing this neighbor to be fast rerouted.

label—A short, fixed-length data identifier that tells switching nodes how to forward data (packets or cells).

LDP—Label Distribution Protocol. The protocol that supports MPLS hop-by-hop forwarding by distributing bindings between labels and network prefixes. The Cisco proprietary version of this protocol is the Tag Distribution Protocol (TDP).

LSP—label-switched path. A configured connection between two routers, in which MPLS is used to carry packets. A path created by the concatenation of one or more label switched hops, allowing a packet to be forwarded by swapping labels from an MPLS node to another MPLS node.

merge point—The tail of the backup tunnel.

MPLS—Multiprotocol Label Switching. A method for forwarding packets (frames) through a network. MPLS enables routers at the edge of a network to apply labels to packets (frames). ATM switches or existing routers in the network core can switch packets according to the labels.

PLR—point of local repair. The headend of the backup tunnel.

RSVP—Resource Reservation Protocol. A protocol that supports the reservation of resources across an IP network. Applications running on IP end systems can use RSVP to indicate to other nodes the nature (bandwidth, jitter, maximum burst, and so on) of the packet streams they want to receive.

state—Information that a router must maintain about each LSP. The information is used for rerouting tunnels.

tailend—The router upon which an LSP is terminated. This is the last router in the LSP's path.

TE—traffic engineering. The techniques and processes used to cause routed traffic to travel through the network on a path other than the one that would have been chosen if standard routing methods had been used.

topology—The physical arrangement of network nodes and media within an enterprise networking structure.

tunnel—Secure communications path between two peers, such as two routers.


Note Refer to Internetworking Terms and Acronyms for terms not included in this glossary.