Configuring OSPFv3 Fast Convergence - LSA and SPF Throttling

Information About OSPFv3 Fast Convergence: LSA and SPF Throttling

The Open Shortest Path First version 3 (OSPFv3) link-state advertisement (LSAs) and shortest-path first (SPF) throttling feature provides a dynamic mechanism to slow down link-state advertisement updates in OSPFv3 during times of network instability. It also allows faster OSPFv3 convergence by providing LSA rate limiting in milliseconds.

OSPFv3 can use static timers for rate-limiting SPF calculation and LSA generation. Although these timers are configurable, the values used are specified in seconds, which poses a limitation on OSPFv3 convergence. LSA and SPF throttling achieves subsecond convergence by providing a more sophisticated SPF and LSA rate-limiting mechanism that is able to react quickly to changes and also provide stability and protection during prolonged periods of instability.

How to Configure OSPFv3 Fast Convergence: LSA and SPF Throttling

The following sections provide configuration information about OSPFv3 Fast Convergence: LSA and SPF throttling.

Tuning LSA and SPF Timers for OSPFv3 Fast Convergence

To tune LSA and SPF timers for OSPFv3 fast convergence, perform this procedure:

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. router ospfv3 [process-id ]
  4. timers lsa arrival milliseconds
  5. timers pacing flood milliseconds
  6. timers pacing lsa-group seconds
  7. timers pacing retransmission milliseconds

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

router ospfv3 [process-id ]

Example:

Device(config)# router ospfv3 1

Enables OSPFv3 router configuration mode for the IPv4 or IPv6 address family.

Step 4

timers lsa arrival milliseconds

Example:

Device(config-rtr)# timers lsa arrival 300

Sets the minimum interval at which the software accepts the same LSA from OSPFv3 neighbors.

Step 5

timers pacing flood milliseconds

Example:

Device(config-rtr)# timers pacing flood 30

Configures LSA flood packet pacing.

Step 6

timers pacing lsa-group seconds

Example:

Device(config-router)# timers pacing lsa-group 300

Changes the interval at which OSPFv3 LSAs are collected into a group and refreshed, checksummed, or aged.

Step 7

timers pacing retransmission milliseconds

Example:

Device(config-router)# timers pacing retransmission 100

Configures LSA retransmission packet pacing in IPv4 OSPFv3.

Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

To configure LSA and SPF throttling for OSPFv3 fast convergence, perform this procedure:

SUMMARY STEPS

  1. enable
  2. configure terminal
  3. ipv6 router ospf process-id
  4. timers throttle spf spf-start spf-hold spf-max-wait
  5. timers throttle lsa start-interval hold-interval max-interval
  6. timers lsa arrival milliseconds
  7. timers pacing flood milliseconds

DETAILED STEPS

  Command or Action Purpose

Step 1

enable

Example:

Device> enable

Enables privileged EXEC mode.

  • Enter your password if prompted.

Step 2

configure terminal

Example:

Device# configure terminal

Enters global configuration mode.

Step 3

ipv6 router ospf process-id

Example:

Device(config)# ipv6 router ospf 1

Enables OSPFv3 router configuration mode.

Step 4

timers throttle spf spf-start spf-hold spf-max-wait

Example:

Device(config-rtr)# timers throttle spf 200 200 200

Turns on SPF throttling.

Step 5

timers throttle lsa start-interval hold-interval max-interval

Example:

Device(config-rtr)# timers throttle lsa 300 300 300

Sets rate-limiting values for OSPFv3 LSA generation.

Step 6

timers lsa arrival milliseconds

Example:

Device(config-rtr)# timers lsa arrival 300

Sets the minimum interval at which the software accepts the same LSA from OSPFv3 neighbors.

Step 7

timers pacing flood milliseconds

Example:

Device(config-rtr)# timers pacing flood 30

Configures LSA flood packet pacing.

Example: Configuring LSA and SPF Throttling for OSPFv3 Fast Convergence

The following example show how to display the configuration values for SPF and LSA throttling timers: 


Device# show ipv6 ospf 

Routing Process "ospfv3 1" with ID 10.9.4.1
Event-log enabled, Maximum number of events: 1000, Mode: cyclic
 It is an autonomous system boundary router
 Redistributing External Routes from, 
    ospf 2  
 Initial SPF schedule delay 5000 msecs 
 Minimum hold time between two consecutive SPFs 10000 msecs 
 Maximum wait time between two consecutive SPFs 10000 msecs 
 Minimum LSA interval 5 secs
 Minimum LSA arrival 1000 msecs

Additional References

Related Documents

Related Topic

Document Title

IPv6 addressing and connectivity

IPv6 Configuration Guide

OSPFv3 Fast Convergence: LSA and SPF Throttling

OSPF Shortest Path First Throttling module

Standards and RFCs

Standard/RFC

Title

RFCs for IPv6

IPv6 RFCs

Feature History for OSPFv3 Fast Convergence: LSA and SPF Throttling

This table provides release and related information for the features explained in this module.

These features are available in all the releases subsequent to the one they were introduced in, unless noted otherwise.

Release

Feature

Feature Information

Cisco IOS XE Gibraltar 16.11.1

OSPFv3 Fast Convergence - LSA and SPF Throttling

The Open Shortest Path First version 3 (OSPFv3) LSAs and SPF throttling feature provides a dynamic mechanism to slow down link-state advertisement updates in OSPFv3 during times of network instability

Use the Cisco Feature Navigator to find information about platform and software image support. To access Cisco Feature Navigator, go to https://cfnng.cisco.com/.