On 12/04/2013 12:57 PM, Sun Paul wrote: > As I know, the A to C and A to D case must have a router in between to form > SCTP multihome topology.
Not necessary. I've produced proper multihoming topologies with just VLANs and different subnet assignment. You can even remove VLANs if you correctly set your arp_ignore and arp_announce values. -vlad > On Dec 4, 2013 10:51 PM, "David Laight" <david.lai...@aculab.com> wrote: > >>>> In normal operation, IP-A sends INIT to IP-X, IP-X returns INIT_ACK to >>>> IP-A. IP-A then sends HB to IP-X, IP-X then returns HB_ACK to IP-A. In >>>> the meantime, IP-B sends HB to IP-Y and IPY returns HB_ACK. >>>> >>>> In case of the path between IP-A and IP-X is broken, IP-B sends INIT >>>> to IP-X, NODE-B uses IP-Y to return INIT_ACK to IP-B. Then IP-B sends >>>> HB to IP-X, and IP-Y returns HB_ACK to IP-B. In the meantime, the HB >>>> communication between IP-B and IP-Y follows the normal flow. >>>> >>>> Can I confirm, is it really valid? >>> >>> As long as NODE-B knows about both IP-A and IP-B, and NODE-A knows about >>> both IP-X and IP-Y (meaning all the addresses were exchanged inside INIT >>> and INIT-ACK), then this situation is perfectly valid. In fact, this >>> has been tested an multiple interops. >> >> There are some network configurations that do cause problems. >> Consider 4 systems with 3 LAN segments: >> A) 10.10.10.1 on LAN X and 192.168.1.1 on LAN Y. >> B) 10.10.10.2 on LAN X and 192.168.1.2 on LAN Y. >> C) 10.10.10.3 on LAN X. >> D) 10.10.10.4 on LAN X and 192.168.1.2 on LAN Z. >> There are no routers between the networks (and none of the systems >> are running IP forwarding). >> >> If A connects to B everything is fine - traffic can use either LAN. >> >> Connections from A to C are problematic if C tries to send anything >> (except a HB) to 192.168.1.1 before receiving a HB response. >> One of the SCTP stacks we've used did send messages to an >> inappropriate address, but I've forgotten which one. >> >> Connections between A and D fail unless the HB errors A receives >> for 192.168.1.2 are ignored. >> >> Of course the application could explicitly bind to only the 10.x address >> but that requires the application know the exact network topology >> and may be difficult for incoming calls. >> >> David >> >> > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
