Hello, I believe I've hit a bug in the BGP implementation of Xorp but before reporting it through bugzilla I want to double check it here. In essence, the problem lies in route advertisements propagation from a 2-byte ASN Xorp instance (old-bgp speaker) to a 4-byte ASN Xorp instance (new-bgp speaker). The simplest way to see it is to configure 3 bgp speakers in the following way: New-bgp (AS 1.0) +----+ Old-bgp (AS 2) +----+ New-bgp (AS 3.0) The way Old-bgp needs to be configured involves two peerings with AS_TRANS (23456) because both AS 1.0 and 3.0 use the AS_TRANS in their open message. Then, suppose that AS 1.0 advertises the prefix 10.100.0.0/16. The route advertisement reaches AS 2 which installs it correctly in its routing table with AS_PATH = 23456. However, AS 3.0 never receives this advertisement from AS 2. In theory, AS 3.0 should get an update message from AS 2 with AS_PATH = 2 23456 and AS4_PATH = 1.0 but this is simply not happening. I've tried to use Quagga as the old-bgp speaker and in this case AS 3.0 receives the update. Unless I've missed some important configuration detail, I believe there is a bug in the way Xorp (doesn't) forward the advertisements for AS_TRANS peers. Both AS 1.0 and 3.0 have enable-4byte-as-numbers: true while AS 2 doesn't.
I can provide more details if necessary. Does it appear as a bug to you? Thanks Marco Canini, Ph.D. EPFL, Networked Systems Laboratory _______________________________________________ Xorp-hackers mailing list [email protected] http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/xorp-hackers
