Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 470)

If a route from a peer exceeds the configured Maximum AS path limit, the device also removes the
same route from that peer, if it exists, from its own RIB.
After a maximum AS path length is configured, the maximum AS path limit applies to all new inbound
routes. To update previously stored routes, you must perform an inbound soft reset for all of the
address families activated for that particular BGP neighbor session.
NOTE
If the neighbor soft-reconfiguration feature is enabled, you must perform a hard reset on the device to
impose the maximum length limit.
NOTE
maxas-limit in is checked against the received AS_PATH and AS4_PATH attributes.
BGP devices check for and, if configured, apply maxas-limit in in the following order:
1. Neighbor value
2. Peer group value
3. Global value
In a case where a neighbor has no maximum AS limit, a peer group has a value of 3 configured,
and the system has a value of 9 configured, all of the devices in the peer group will only use the
peer group value; the global value will never be used.
Setting a global maximum AS path limit
The syntax for the global maximum AS path limit command is:
Syntax: [no] maxas-limit in num
The maxas-limit keyword specifies the limit on the AS numbers in the as-path attribute. The in
keyword allows the as-path attribute from any neighbor imposing a limit on AS numbers received. The
default maximum length for the global system is 300. The range is 0 - 300. The no keyword removes
the configuration at the global level.
NOTE
The device applies the BGP4 maximum AS path limit on a per virtual device basis.
To configure the global Maximum AS path limit to 15, enter the following command:
device(config-bgp)# maxas-limit in 15
Setting a maximum AS path limit for a peer group or neighbor
To set maximum AS path limit for a peer group or a neighbor, the syntax is:
Syntax: neighbor { ip-addr | peer-group-name } maxas-limit in [ num | disable ]
By default, neighbors or peer groups have no configured maximum values. The range is 0 - 300. The
disable keyword is used to stop a neighbor from inheriting the configuration from the peer-group or
global and to the use system default value.
Setting a global maximum AS path limit
470 FastIron Ethernet Switch Layer 3 Routing Configuration Guide
53-1003087-04