From: Lanny Ballard (lanny26ga@hotmail.com)
Date: Wed May 25 2005 - 08:49:43 GMT-3
Upon further consideration, I'm going to have to assume that configuring
ospf over 6to4 tunnels is not possible. With other tunnels, like Isatap,
the network is the same and the host ID is different on the tunnels;
however, with 6to4, the actual network address on each end of the tunnel is
different. which is why I believe ospf was getting stuck in the exstart
state.
Does this make sense? Has anybody seen a situation in which ospf will form
an adjacency with a neighbor that isn't on the same network?
You were correct in stating that OSPF still believes that the tunnels are
p2p; however, i have not been able to get an automatic to work using a p2p
network. In order to get it to work i have had to change it to nbma and
specify neighbors. Is there an easier way to do this?
Lanny
>From: "Sean C" <Upp_and_Upp@hotmail.com>
>Reply-To: "Sean C" <Upp_and_Upp@hotmail.com>
>To: "GroupStudy" <ccielab@groupstudy.com>
>Subject: Re: ipv6 ospf
>Date: Tue, 24 May 2005 21:44:27 -0400
>
>Hi Lanny,
>
>2 things:
>1-I've always thought that the default for OSPF tunnels is point-to-point -
>IPv4 or IPv6. But I see where you can assume different from the CD:
>http://www.cisco.com/univercd/cc/td/doc/product/software/ios123/123cgcr/ipv6_c/sa_tunv6.htm#wp1048589
>"The key difference between automatic 6to4 tunnels and manually configured
>tunnels is that the tunnel is not point-to-point; it is
>point-to-multipoint. In automatic 6to4 tunnels, routers are not configured
>in pairs because they treat the IPv4 infrastructure as a virtual
>nonbroadcast multiaccess (NBMA) link."
>Have read that, I have to think that the router still assumes an 6to4
>tunnel would use an OSPF network type of point-to-point. Hard to explain,
>but I think while the router will allow the tunnel to be NBMA, OSPF doesn't
>care - it sees the tunnel as a p2p unless told otherwise. Perhaps someone
>else can verify or explain this better.
>
>2-Can you post your configs? Perhaps it's as something as simple as the
>hex is wrong. I got stuck on my first 6to4 tunnel for 30 mins simply
>because I designated my source IP, not my source interface (hope that makes
>sense). Anyway, configs help us help you.
>
>HTH,
>Sean
>----- Original Message ----- From: "Lanny Ballard" <lanny26ga@hotmail.com>
>To: <ccielab@groupstudy.com>
>Sent: Tuesday, May 24, 2005 7:50 PM
>Subject: ipv6 ospf
>
>
>>I'm trying to get ospf running over an ipv6 tunnel
>>I'm using a 6to4 tunnel, and i can ping each end.
>>My understanding is that automatic tunnels are treated as nbma or
>>point-to-multipoint
>>
>>I noticed under sh ipv6 ospf int, that the tunnel was considered as
>>point-to-point even after I enabled ospf on it. I changed the network
>>type to point-to-multipoint with no luck. I then changed it to
>>Non-broadcast and manually configured ipv6 ospf neighbors, but still no
>>luck, they got stuck in the Exstart state. They kept on retransmitting
>>the DBDs, it was like the DBDs got lost or something. It is not an MTU
>>error, seeing as how I have ipv6 ospf mtu-ignore on both sides of the
>>tunnel.
>>
>>I think I'm just missing a basic configuration here. Can someone help?
>>
>>TIA
>>Lanny
>>
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