Specifications

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Cisco Nexus 3000 Series NX-OS Unicast Routing Configuration Guide, Release 5.0(3)U2(2)
OL-25782-02
Chapter 6 Configuring Advanced BGP
Configuring Advanced BGP
To disable checking whether or not a single-hop eBGP peer is directly connected, use the following
command in neighbor configuration mode:
Configuring eBGP Multihop
You can configure the eBGP time-to-live (TTL) value to support eBGP multihop. In some situations, an
eBGP peer is not directly connected to another eBGP peer and requires multiple hops to reach the remote
eBGP peer. You can configure the eBGP TTL value for a neighbor session to allow these multihop
sessions.
To configure eBGP multihop, use the following command in neighbor configuration mode:
Disabling a Fast External Failover
Typically, when a BGP router loses connectivity to a directly connected eBGP peer, BGP triggers a fast
external failover by resetting the eBGP session to the peer. You can disable this fast external failover to
limit the instability caused by link flaps.
To disable fast external failover, use the following command in router configuration mode:
Command Purpose
disable-connected-check
Example:
switch(config-router-neighbor)#
disable-connected-check
Disables checking whether or not a single-hop
eBGP peer is directly connected. You must
manually reset the BGP sessions after using this
command.
Command Purpose
ebgp-multihop ttl-value
Example:
switch(config-router-neighbor)#
ebgp-multihop 5
Configures the eBGP TTL value for eBGP
multihop. The range is from 2 to 255. You must
manually reset the BGP sessions after using this
command.
Command Purpose
no fast-external-failover
Example:
switch(config-router)# no
fast-external-failover
Disables a fast external failover for eBGP peers.
This command is enabled by default.