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| -rw-r--r-- | doc/bird.sgml | 27 |
1 files changed, 27 insertions, 0 deletions
diff --git a/doc/bird.sgml b/doc/bird.sgml index edc871fb..e0b60c81 100644 --- a/doc/bird.sgml +++ b/doc/bird.sgml @@ -3269,6 +3269,8 @@ protocol ospf [v2|v3] <name> { tick <num>; ecmp <switch> [limit <num>]; merge external <switch>; + graceful restart <switch>|aware; + graceful restart time <num>; area <id> { stub; nssa; @@ -3412,6 +3414,31 @@ protocol ospf [v2|v3] <name> { from different LSAs are treated as separate even if they represents the same destination. Default value is no. + <tag><label id="ospf-graceful-restart">graceful restart <m/switch/|aware</tag> + When an OSPF instance is restarted, neighbors break adjacencies and + recalculate their routing tables, which disrupts packet forwarding even + when the forwarding plane of the restarting router remains intact. + <rfc id="3623"> specifies a graceful restart mechanism to alleviate this + issue. For OSPF graceful restart, restarting router originates + Grace-LSAs, announcing intent to do graceful restart. Neighbors + receiving these LSAs enter helper mode, in which they ignore breakdown + of adjacencies, behave as if nothing is happening and keep old routes. + When adjacencies are reestablished, the restarting router flushes + Grace-LSAs and graceful restart is ended. + + This option controls the graceful restart mechanism. It has three + states: Disabled, when no support is provided. Aware, when graceful + restart helper mode is supported, but no local graceful restart is + allowed (i.e. helper-only role). Enabled, when the full graceful restart + support is provided (i.e. both restarting and helper role). Note that + proper support for local graceful restart requires also configuration of + other protocols. Default: aware. + + <tag><label id="ospf-graceful-restart-time">graceful restart time <m/num/</tag> + The restart time is announced in the Grace-LSA and specifies how long + neighbors should wait for proper end of the graceful restart before + exiting helper mode prematurely. Default: 120 seconds. + <tag><label id="ospf-area">area <M>id</M></tag> This defines an OSPF area with given area ID (an integer or an IPv4 address, similarly to a router ID). The most important area is the |