bird and OSPF on p2p

[Ondrej Zajicek]

On Wed, Aug 22, 2012 at 04:32:24PM +0600, Eugene M. Zheganin wrote:
> Hi.
>
> On 22.08.2012 14:39, Ondrej Zajicek wrote:
>> As i understand it correctly, you have Quagga at one end and BIRD
>> on the other? AFAIK there is some problem related to unnumbered
>> ptp links in Quagga which causes incompatibility with BIRD,
>> Joakim Tjernlund has some patches for that for Quagga.
> As far as I understand unnumbered interfaces are those that have  
> something like this
>
> interface Loopback0
> ip address 1.1.1.1/255.255.255.255
> !
> interface Tunnel0
> ip unnumbered Loopback0
>
> And I have no knowledge about quagga possibilities here, and no such  
> configuration in my quagga too.
...
> Excuse me, but why do you consider /32 prefix as improper ?

Generally, i consider that network has proper IP prefix if all
interfaces connected to that network share that prefix [*] (i.e.
192.168.1.10 and 192.168.1.20 in 192.168.1.0/24, or even 192.168.1.10
and 192.168.1.11 in 192.168.1.10/31). This is usual network setup.

Another possibility is 'unnumbered' as you wrote above (i.e. IP address
just for loopback). Third possibility is 'ptp' addressing as set
by 'ip addr add 192.168.1.10 peer 192.168.1.20' on Linux.

I am not sure whether these two other possibilities are standardized in
some RFC (i suppose they are just some nonstandard but common
extensions). Esp. 'ptp' addressing is not discussed in OSPF RFC.

I always considered the 'ptp' addressing as a variant of
real 'unnumbered' addressing, as it is in most ways very similar
to 'real' unnumbered variant - you just give a hint what is
IP of the other side, which is useful for running pseudo-unnumbered
links on broadcast media like ethernet, where you could have several
problems with 'real' unnumbered setups.

There are some assumptions that depend on how you consider 'ptp'
addressing. For example whether these 'ptp' addresses have to be unique
on each iface or whether you could share local IP between several
ifaces.

[*] for simplicity assume one IP per iface and one prefix per network.




But back to your problem. Perhaps i jumped to conclusions here. When i
looked at the output you sent it seemed that Quagga does not have BIRD
as neighor, while BIRD has Quagga as full/ptp, is this true? That would
be probably different problem, as the mentioned one is related to
routing table calculation, not neighbor establishment.

You could also try the attached patch for BIRD, if the connection works
with it, then it is the mentioned problem.

-- 
Elen sila lumenn' omentielvo

Ondrej 'SanTiago' Zajicek (email: santiago at crfreenet.org)
OpenPGP encrypted e-mails preferred (KeyID 0x11DEADC3, wwwkeys.pgp.net)
"To err is human -- to blame it on a computer is even more so."
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