Bgp Local Label Retention; Command Line Interface (Cli) Consistency For Bgp Commands - Cisco ASR 9000 Series Routing Configuration Manual
Aggregation services router
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- Command reference manual (1138 pages) ,
- Reference manual (696 pages) ,
- Configuration manuallines (694 pages)
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Implementing BGP
NSR does not force any software upgrades on other routers in the network, and peer routers are not required
to support NSR.
When a route processor switchover occurs due to a fault, the TCP connections and the BGP sessions are
migrated transparently to the standby route processor, and the standby route processor becomes active. The
existing protocol state is maintained on the standby route processor when it becomes active, and the protocol
state does not need to be refreshed by peers.
Events such as soft reconfiguration and policy modifications can trigger the BGP internal state to change. To
ensure state consistency between active and standby BGP processes during such events, the concept of post-it
is introduced that act as synchronization points.
BGP NSR provides the following features:
• NSR-related alarms and notifications
• Configured and operational NSR states are tracked separately
• NSR statistics collection
• NSR statistics display using show commands
• XML schema support
• Auditing mechanisms to verify state synchronization between active and standby instances
• CLI commands to enable and disable NSR
• Support for 5000 NSR sessions
BGP Local Label Retention
When a primary PE-CE link fails, BGP withdraws the route corresponding to the primary path along with its
local label and programs the backup path in the Routing Information Base (RIB) and the Forwarding Information
Base (FIB), by default.
However, until all the internal peers of the primary PE reconverge to use the backup path as the new bestpath,
the traffic continues to be forwarded to the primary PE with the local label that was allocated for the primary
path. Hence the previously allocated local label for the primary path must be retained on the primary PE for
some configurable time after the reconvergence. BGP Local Label Retention feature enables the retention of
the local label for a specified period. If no time is specified, the local lable is retained for a default value of
five minutes.
The retain local-label command enables the retention of the local label until the network is converged.
Command Line Interface (CLI) Consistency for BGP Commands
From Cisco IOS XR Release 3.9.0 onwards, the Border Gateway Protocol (BGP) commands use disable
keyword to disable a feature. The keyword inheritance-disable disables the inheritance of the feature
properties from the parent level.
Cisco ASR 9000 Series Aggregation Services Router Routing Configuration Guide, Release 5.3.x
BGP Local Label Retention
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