By default, neighbors or peer groups have no congured maximum values. The range is 0 - 300. The disable keyword is used to stop a
neighbor from inheriting the conguration from the peer-group or global and to the use system default value.
To congure a peer group named "PeerGroup1" and set a maximum AS path value of 7, enter the following commands:
device(config-bgp)# neighbor PeerGroup1 peer-group
device(config-bgp)# neighbor PeerGroup1 maxas-limit in 7
BGP4 max-as error messages
This section lists error log messages that you might see when the device receives routes that exceed the congured AS segment limit or
the internal memory limit. The log messages can contain a maximum of 30 ASNs. If a message contains more than 30 ASNs, the
message is truncated and an ellipsis appears.
Maximum AS path limit error
SYSLOG: <11>Jan 1 00:00:00 mu1, BGP: From Peer 192.168.1.2 received Long AS_PAT H= AS_CONFED_SET(4) 1 2 3
AS_CONFED_SEQUENCE(3) 4 AS_SET(1) 5 6 7 AS_SEQ(2) 8 9 attribute length (9) More than configured MAXAS-LIMIT
7
Memory limit error
SYSLOG: <11>Jan 1 00:00:00 mu1, BGP: From Peer 192.168.1.2 received Long AS_PAT H= AS_CONFED_SET(4) 1 2 3
AS_CONFED_SEQUENCE(3) 4 AS_SET(1) 5 6 7 AS_SEQ(2) 8 9 attribute length (9) Exceeded internal memory limit
NOTE
The device generates a log message one time every two minutes. Because of this rate limit, it is possible that some errors might
not appear in the log. In this case, you can use the debug ip bgp events command to view errors pertaining to the maxas-limit
value and the actual AS path attributes received.
Originating the default route
By default, the device does not originate and advertise a default route using BGP4. A BGP4 default route is the IP address 0.0.0.0 and
the route
prex 0 or network mask 0.0.0.0. For example, 0.0.0.0/0 is a default route.
NOTE
The device checks for the existence of an IGP route for 0.0.0.0/0 in the IP route table before creating a local BGP4 route for
0.0.0.0/0.
To congure the device to originate and advertise a default BGP4 route, enter this command.
device(config-bgp)# default-information-originate
Syntax: [no] default-information-originate
Changing the default metric used for route cost
By default, BGP4 uses the BGP MED value as the route cost when adding the route to the RTM. However, you can
congure BGP4 to
use the IGP cost instead.
BGP4 max-as error messages
FastIron Ethernet Switch Layer 3 Routing
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