init-route-calc-delay

Enables BGP delayed route calculation in specific scenarios: router reload, BGP process restart, and admin reset of all the BGP peers in a VRF/SAFI using the clear ip | ipv6 bgp neighbor all command. BGP BEST-path selection is delayed until BGP has the route update information from all of its RIB-IN peers.

Syntax

init-route-calc-delay [ min-delay min_secs| max-delay max_secs | msg-idle-time idle_secs]

no init-route-calc-delay [ min-delay | max-delay | msg-idle-time ]

Command Default

By default, BGP delayed route calculation is disabled.

Parameters

min-delay min_secs: Specifies the minimum delay time in seconds by which the BGP BEST-path selection is delayed. Enter an integer from 60 to 900. When the delay route calculation is enabled, the default is 180 seconds.
max-delay max_secs: Specifies the maximum delay time in seconds by which the BGP BEST-path selection is delayed. Enter an integer from 180 to 900. When the delay route calculation is enabled, the default is 300 seconds.
msg-idle-time idle_secs: Specifies the message idle time in seconds to detect the end of the learning phase for a peer. A peer is moved out of the learning phase if the time difference between subsequent update messages from the peer exceeds the message idle time. Enter an integer from 1 to 60. When the delay route calculation is enabled, the default is 2 seconds.

Modes

BGP configuration mode

Usage Guidelines

Use the no init-route-calc-delay command to disable the delay route calculation. When an optional keyword is include with the no form of this command, it resets the default setting for the keyword.

If you enter the init-route-calc-delay command without any options, the default settings for the minimum and maximum delay and message idle time are used.

TCP is the underlying transport mechanism used by BGP for propagating BGP update messages. Optimal usage of TCP directly helps in improving BGP performance and convergence. Configuring higher IP MTU values (4500 bytes) for the interfaces through which BGP peer IP connectivity is established helps to select optimal MSS size for BGP TCP sessions.

Examples

The following example enables the BGP delay route calculation.

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# init-route-calc-delay

The following example configures the minimum delay time to 200 seconds.

device# configure terminal
device(config)# router bgp
device(config-bgp-router)# init-route-calc-delay min-delay 200