Deployment Guide
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.2(0.0) Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information
This command is enabled by default, that is for all updates received from EBGP peers, BGP ensures that the rst
AS of the rst AS segment is always the AS of the peer. If not, the update is dropped and a counter is increments.
To view the “failed enforce-rst-as check” counter, use the show ip bgp neighbors command.
If you disable the enforce-first-as command, it can be viewed using the show ip protocols command.
Related Commands
show ip bgp neighbors — views the information the BGP neighbors exchange.
show ip protocols — views information on routing protocols.
bgp fast-external-failover
Enable the fast external failover feature, which immediately resets the BGP session if a link to a directly connected external peer fails.
Syntax
bgp fast-external-failover
To disable fast external failover, use the no bgp fast-external-failover command.
Defaults Enabled
Command Modes ROUTER BGP
Supported Modes Full–Switch
Command History
Version Description
9.9(0.0) Introduced on the FN IOM.
9.2(0.0) Introduced on the MXL 10/40GbE Switch IO Module.
Usage Information
The bgp fast-external-failover command appears in the show config command output.
bgp four-octet-as-support
Enable 4-byte support for the BGP process.
Syntax
bgp four-octet-as-support
To disable fast external failover, use the no bgp four-octet-as-support command.
Defaults Disabled (supports 2–byte format)
Command Modes ROUTER BGP
Supported Modes Full–Switch
Border Gateway Protocol IPv4 (BGPv4) 297