> Are you saying that if you have multiple interfaces on the same subnet, > they must be in an IPMP group, or the config is broken?
Yes -- though the issue is really with having multiple interfaces on the same link, rather than the same subnet. > Or if you have multiple IP addresses (on the same subnet) on the same > interface, it is broken? The latter does not seem so, but want to make > sure Right, that is fine -- in fact, it is an extremely common configuration. > > With IPMP, outbound interface selection is determined in a round-robin > > fashion the first time an application attempts to send to a particular > > destination that does not yet have an IRE cache entry. > > See illgrp_scheduler() for details. > > For servers expecting connections to be established from a client, will > the IRE entry be set on the initial incoming datagram? Or the first > outgoing? Tobias' setup suggests that some responses go out one > interface, and others a different one. It will be set up when the server first needs to contact the client. In the case of a TCP connection, this will be done in the kernel as part of the three-way handshake in tcp_conn_request() -- so, for TCP, it is effectively a set on the initial incoming datagram (TCP SYN). > Is this due to the fact that there are, based my expectation of the > first part, multiple interfaces on the same subnet but not in an IPMP > group, therefore not associated correctly. Sorry, what is "this" in "is this due to the fact"? > I still don't understand the IRE behavior differences when IPMP is > enable vs. when not. Even after having tried to make sense of it > multiple times since IPMP was delivered. What differences are you referring to? The primary difference is that we round-robin across the available interfaces; this is necessary for outbound load-spreading. A consequence of this is that one cannot predict what interface in the group packets will be sent on. However, once an IRE cache entry to a particular destination has been created, the outgoing interface will remain constant until the IRE cache entry is removed. -- meem _______________________________________________ zones-discuss mailing list email@example.com