Brocade FastIron Ethernet Switch Layer 3 Routing Configuration Guide - Manual (Page 392)

FIGURE 29 Management module switchover behavior for BGP4 peer notification
If the active management module fails due to a fault, the management module does not have the
opportunity to reset BGP4 sessions with neighbors as described for intentional failovers. In this
situation the management module will reboot, or the standby management module becomes the new
active management module. Since the new active management module does not have the TCP/BGP4
information needed to reset the previous sessions, a remote BGP4 peer session is only reset when it
sends a BGP4/TCP keep-alive packet to this device, or when the BGP4 hold-time expires.
To help reduce the reconnection time after a management module failover or system reload, if an
incoming TCP packet contains an MD5 digest, and no matching TCP session is found, the device
attempts to find a matching BGP4 peer based on the IP address. If a BGP4 peer configuration can be
found, the device looks up the MD5 password configured for the peer, and uses it to send a RESET
packet.
BGP4 neighbor local AS
This feature allows you to configure a device so that it adds a peer to an AS that is different from the
AS to which it actually belongs. This feature is useful when an ISP is acquired by another ISP. In this
situation, customers of the acquired ISP might not want to (or might not be able to) adjust their
configuration to connect to the AS of the acquiring provider.
In this example, Customer C is connected to ISP-A which is in AS 100 and ISP-B which is in AS 200.
BGP4 neighbor local AS
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