[Xorp-users] OSPFv2 P2P still uses 224.0.0.5
Christian Svensson
info at cmd.nu
Sun Apr 27 22:46:05 PDT 2008
Hi,
I see. I will look into using virtual links, maybe the solution for me
lies there.
Thanks!
On Mon, Apr 28, 2008 at 5:01 AM, Atanu Ghosh <atanu at icsi.berkeley.edu> wrote:
> Hi.
>
> The specification requires that the destination address for
> point-to-point networks is 225.0.0.5.
>
> RFC 2328 A.1 Encapsulation of OSPF packets
> ----------------------------------------
> AllSPFRouters
> This multicast address has been assigned the value
> 224.0.0.5. All routers running OSPF should be prepared to
> receive packets sent to this address. Hello packets are
> always sent to this destination. Also, certain OSPF
> protocol packets are sent to this address during the
> flooding procedure.
> ----------------------------------------
>
> RFC 2328 8.1. Sending protocol packets
> ----------------------------------------
> The IP destination address for the packet is selected as
> follows. On physical point-to-point networks, the IP
> destination is always set to the address AllSPFRouters. On all
> other network types (including virtual links), the majority of
> OSPF packets are sent as unicasts, i.e., sent directly to the
> other end of the adjacency. In this case, the IP destination is
> just the Neighbor IP address associated with the other end of
> the adjacency (see Section 10). The only packets not sent as
> unicasts are on broadcast networks; on these networks Hello
> packets are sent to the multicast destination AllSPFRouters, the
> Designated Router and its Backup send both Link State Update
> Packets and Link State Acknowledgment Packets to the multicast
> address AllSPFRouters, while all other routers send both their
> Link State Update and Link State Acknowledgment Packets to the
> multicast address AllDRouters.
> ----------------------------------------
>
> Atanu.
>
> >>>>> "Christian" == Christian Svensson <info at cmd.nu> writes:
>
> Christian> Hello.
> Christian> My configuration looks like this:
>
> Christian> area 0.0.0.3 {
> Christian> area-type: "normal"
> Christian> interface "eth0" {
> Christian> link-type: "p2p"
> Christian> vif "eth0" {
> Christian> address 10.254.0.1 {
> Christian> priority: 128
> Christian> hello-interval: 10
> Christian> router-dead-interval: 40
> Christian> interface-cost: 5
> Christian> retransmit-interval: 5
> Christian> transit-delay: 1
> Christian> passive: false
> Christian> neighbor 10.254.0.2 {
> Christian> router-id: 10.254.0.2
> Christian> }
> Christian> disable: false
> Christian> }
> Christian> }
> Christian> }
> Christian> }
>
> Christian> Looking at the packets that passes out of eth0, the only ones that
> Christian> seems to be OSPF-related are heading towards 224.0.0.5. My link
> Christian> between 10.254.0.1 and 10.254.0.2 strips some undocumented segments
> Christian> from packets and it does not handle multicast at all, thus I'm looking
> Christian> for a way of using unicast instead of multicast for inter-router
> Christian> communications. Looking at the OSPFv2 RFC and the P2P mode it appears
> Christian> that this is what I'm looking for but I could be wrong.
>
> Christian> Using Xorp 1.4.
>
> Christian> Greetings,
> Christian> --
> Christian> Christian Svensson
> Christian> Command Systems
>
> Christian> _______________________________________________
> Christian> Xorp-users mailing list
> Christian> Xorp-users at xorp.org
> Christian> http://mailman.ICSI.Berkeley.EDU/mailman/listinfo/xorp-users
>
--
Christian Svensson
Command Systems
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