[quagga-users 5678] OSPF and PPP interfaces

[Svetlana Atanasova]

Hello,

I have a problem with ospfd using quagga-0.98.5
It tries to add a multicast address on every PPP interface and
doesn't recognize that it's point-to-point type of network. I have
a lot of dynamic PPP interfaces, and when their count reaches
kernel (or maybe ospf daemon) maximum for multicast interfaces ospfd
starts to send
inconsistent LSA-updates looking like this:
IP (tos 0x0, ttl 1, id 40842, offset 0, flags [+], length: 1500)
X.X.X.X > 224.0.0.6: OSPFv2, LS-Update (4), length: 1480 [len 1528]
They doesn't contain Router-ID neither any other information.
Designated router which receives this updates (cisco router in this
case) produces error %OSPF-4-BADLSATYPE
Previously I used zebra-0.94 and I don't have this problem
because every PPP was recognized as point-to-point network.
Does anybody know any solution?

Regards,
Svetlana

[Andrew J. Schorr]

Hi,

Post by Svetlana Atanasova
I have a problem with ospfd using quagga-0.98.5
It tries to add a multicast address on every PPP interface and
doesn't recognize that it's point-to-point type of network.

Why do you say that it does not recognize that it's a PtP network?
What is the output of zebra "show interface" and ospfd
"show ip ospf interface"?

But yes, you are correct, quagga/ospfd definitely uses multicast
on PtP interfaces.

Post by Svetlana Atanasova
I have a lot of dynamic PPP interfaces, and when their count reaches
kernel (or maybe ospf daemon) maximum for multicast interfaces

If that's the problem, you should probably be able to increase
the limit. The procedure for doing this probably depends on which
platform you are using...

Post by Svetlana Atanasova
Previously I used zebra-0.94 and I don't have this problem
because every PPP was recognized as point-to-point network.
Does anybody know any solution?

I just downloaded the zebra-0.94 code, and it certainly looks as if it also
uses multicast on PtP links. In particular, if you look in the
ospf/ospf_interface.c:ospf_if_up() function, it joins the OSPF-all-routers
multicast group for all interface types other than loopback and virtual-link.
So I'm not sure why zebra-0.94 was working better, but I don't think
this is the issue.

Regards,
Andy

[Svetlana Atanasova]

Hello,

thank you for replay. I'm not sure what exactly causes this
problem but the fact is that zebra-0.94 works fine, but quagga
doesn't :( I decide that the problem is in number of PPP interfaces
because before starting pppoe server everything was OK.

Post by Andrew J. Schorr
Hi,

Post by Svetlana Atanasova
I have a problem with ospfd using quagga-0.98.5
It tries to add a multicast address on every PPP interface and
doesn't recognize that it's point-to-point type of network.

Why do you say that it does not recognize that it's a PtP network?
What is the output of zebra "show interface" and ospfd
"show ip ospf interface"?
But yes, you are correct, quagga/ospfd definitely uses multicast
on PtP interfaces.

I noticed that zebra-0.94 adds in configuration
ip ospf network point-to-point
and quagga doesn't, but may be it doesn't matter. PPP interfaces
are not actually OSPF interfaces, they aren't in any area, so the output
from "show ip ospf interface" command is not very significant :)

Post by Andrew J. Schorr

Post by Svetlana Atanasova
I have a lot of dynamic PPP interfaces, and when their count reaches
kernel (or maybe ospf daemon) maximum for multicast interfaces

If that's the problem, you should probably be able to increase
the limit. The procedure for doing this probably depends on which
platform you are using...

I'm running quagga on Slackware 10.2. I tried to increase the limit in the
kernel and number of this "empty" LSA updates decreased, but they still
appear in tcpdump and the Cisco routers still log corrupted OSPF packets.

Post by Andrew J. Schorr

Post by Svetlana Atanasova
Previously I used zebra-0.94 and I don't have this problem
because every PPP was recognized as point-to-point network.
Does anybody know any solution?

I just downloaded the zebra-0.94 code, and it certainly looks as if it also
uses multicast on PtP links. In particular, if you look in the
ospf/ospf_interface.c:ospf_if_up() function, it joins the OSPF-all-routers
multicast group for all interface types other than loopback and virtual-link.
So I'm not sure why zebra-0.94 was working better, but I don't think
this is the issue.
Regards,
Andy
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...

[Andrew J. Schorr]

Post by Svetlana Atanasova
thank you for replay. I'm not sure what exactly causes this
problem but the fact is that zebra-0.94 works fine, but quagga
doesn't :( I decide that the problem is in number of PPP interfaces
because before starting pppoe server everything was OK.

Perhaps you can post your zebra.conf and ospfd.conf?

Post by Svetlana Atanasova
I noticed that zebra-0.94 adds in configuration
ip ospf network point-to-point
and quagga doesn't, but may be it doesn't matter.

It probably doesn't matter. How does the output of "show interface"
differ bewteen the two?

Post by Svetlana Atanasova
PPP interfaces
are not actually OSPF interfaces, they aren't in any area, so the output
from "show ip ospf interface" command is not very significant :)

If the PPP interfaces are not running OSPF, then there should be no
reason for ospfd to join multicast groups on those interfaces. What
exactly is the output of "show ip ospf interface"?

And what multicast memberships are actually active on your system?
What's the output of "netstat -g"?

Also, what does the configuration of the PPP links look like?
Is this linux? What's the output of /sbin/ip addr ls?

Regards,
Andy

[Svetlana Atanasova]

Post by Andrew J. Schorr

Post by Svetlana Atanasova
thank you for replay. I'm not sure what exactly causes this
problem but the fact is that zebra-0.94 works fine, but quagga
doesn't :( I decide that the problem is in number of PPP interfaces
because before starting pppoe server everything was OK.

Perhaps you can post your zebra.conf and ospfd.conf?

I don't think that it's configuration problems. Before moving pppoe
server here everything works without any errors.

Post by Andrew J. Schorr

Post by Svetlana Atanasova
I noticed that zebra-0.94 adds in configuration
ip ospf network point-to-point
and quagga doesn't, but may be it doesn't matter.

It probably doesn't matter. How does the output of "show interface"
differ bewteen the two?

Post by Svetlana Atanasova
PPP interfaces
are not actually OSPF interfaces, they aren't in any area, so the output
from "show ip ospf interface" command is not very significant :)

If the PPP interfaces are not running OSPF, then there should be no
reason for ospfd to join multicast groups on those interfaces. What
exactly is the output of "show ip ospf interface"?

...

Oops. You are absolutely right about adding interfaces to multicast groups.
I'm misled because the only strange messages I saw in the ospfd logs was
about exceeding
the allowed number of multicast interfaces. The system is Slackware
10.2, but now I
can't perform any tests. I'm running zebra again because after working
with this errors
ospf crashes with out of memory.

Post by Andrew J. Schorr
And what multicast memberships are actually active on your system?
What's the output of "netstat -g"?
Also, what does the configuration of the PPP links look like?
Is this linux? What's the output of /sbin/ip addr ls?
Regards,
Andy

[Andrew J. Schorr]

Post by Svetlana Atanasova
Oops. You are absolutely right about adding interfaces to multicast groups.
I'm misled because the only strange messages I saw in the ospfd logs was
about exceeding
the allowed number of multicast interfaces. The system is Slackware
10.2, but now I
can't perform any tests. I'm running zebra again because after working
with this errors
ospf crashes with out of memory.

Well, I'm not sure what the problem is, but I think we would need more
information to understand what is happening. A good start is usually
to post your zebra.conf & ospfd.conf files, plus the output from
"/sbin/ip addr ls" plus "show interface" and "show ip ospf interface".

Regards,
Andy