Configuring Bgp Next-Hop Address Tracking; Configuring Next-Hop Filtering - Cisco Nexus 7000 Series Configuration Manual

Chapter 11 Configuring Advanced BGP
S e n d d o c u m e n t c o m m e n t s t o n e x u s 7 k - d o c f e e d b a c k @ c i s c o . c o m .
Command
next-hop-self
Example:
switch(config-router-neighbor-af)#
next-hop-self
next-hop-third-party
Example:
switch(config-router-neighbor-af)#
next-hop-third-party

Configuring BGP Next-Hop Address Tracking

BGP next-hop address tracking is enabled by default and cannot be disabled.
You can modify the delay interval between RIB checks to increase the performance of BGP next-hop
tracking.
To modify the BGP next-hop address tracking, use the following commands address-family
configuration mode:
Command
nexthop trigger-delay {critical |
non-critical} milliseconds
Example:
switch(config-router-af)# nexthop
trigger-delay critical 5000

Configuring Next-Hop Filtering

BGP next-hop filtering allows you to specify that when a next-hop address is checked with the RIB, the
underlying route for that next-hop address is passed through the route map. If the route map rejects the
route, the next-hop address is treated as unreachable.
BGP marks all next hops that are rejected by the route policy as invalid and does not calculate the best
path for the routes that use the invalid next-hop address.
To configure BGP next-hop filtering, use the following command in address-family configuration mode:
OL-20002-02
Purpose
Uses the local BGP speaker address as the next-hop
address in route updates. This command triggers an
automatic soft clear or refresh of BGP neighbor
sessions.
Sets the next-hop address as a third-party address.
Use this command for single-hop EBGP peers that
do not have next-hop-self configured
Purpose
Specifies the next-hop address tracking delay timer
for critical next-hop reachability routes and for
noncritical routes. The range is from 1 to
4294967295 milliseconds. The critical timer
default is 3000. The noncritical timer default is
10000.
Cisco Nexus 7000 Series NX-OS Unicast Routing Configuration Guide, Release 4.x
Configuring Advanced BGP
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