Brocade Multi-Service IronWare Routing Configuration Guide (Supporting R05.6.00) - Manual (Page 70)

42 Multi-Service IronWare Routing Configuration Guide
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Enabling fast external fallover
Enabling fast external fallover
BGP4 devices rely on KEEPALIVE and UPDATE messages from neighbors to signify that the
neighbors are alive. For BGP4 neighbors that are two or more hops away, such messages are the
only indication that the BGP4 protocol has concerning the alive state of the neighbors. As a result,
if a neighbor becomes non-operational, the device waits until the Hold Time expires or the TCP
connection fails before concluding that the neighbor is not operational and closing its BGP4
session and TCP connection with the neighbor.
The device waits for the Hold Time to expire before ending the connection to a directly-attached
BGP4 neighbor that becomes non-operational.
For directly-attached neighbors, the device immediately senses loss of a connection to the
neighbor from a change of state of the port or interface that connects the device to the neighbor.
For directly-attached EBGP neighbors, the device uses this information to immediately close the
BGP4 session and TCP connection to locally attached neighbors that become non-operational.
NOTE
The fast external failover feature applies only to directly attached EBGP neighbors. The feature does
not apply to IBGP neighbors.
To enable fast external fallover, enter the following command.
Brocade(config-bgp)# fast-external-fallover
To disable fast external fallover again, enter the following command.
Brocade(config-bgp)# no fast-external-fallover
Syntax: [no] fast-external-fallover
Setting the local AS number
The local autonomous system number (ASN) identifies the AS in which the BGP4 device resides.
To set the local AS number, enter commands such as the following.
Brocade(config)# router bgp
BGP4: Please configure 'local-as' parameter in order to enable BGP4.
Brocade(config-bgp)# local-as 10
Brocade(config-bgp)# write memory
Syntax: [no] local-as num
The num parameter specifies a local AS number in the range 1 – 4294967295. It has no default.
AS numbers 64512 – 65535 are the well-known private BGP4 AS numbers and are not advertised
to the Internet community.
Setting the local AS number for VRF instances
The local autonomous system (AS) number identifies the AS in which the BGP4 device resides.
In releases prior to NetIron R05.3.00, you can assign only a single BGP AS number for the entire
system, including instances of BGP VRF. In NetIron R05.3.00, you can assign different BGP AS
numbers for each VRF instance. If you do not assign an AS number, the BGP VRF instances use the
default BGP AS number, as in previous releases.