RE: 0.0.0.1 on OSPF hello

From: Brian McGahan (bmcgahan@internetworkexpert.com)
Date: Wed May 04 2005 - 16:27:52 GMT-3


What exactly are you trying to accomplish/troubleshoot? Post your relevant configs and show outputs.

Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com

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________________________________________
From: gladston@br.ibm.com [mailto:gladston@br.ibm.com]
Sent: Wednesday, May 04, 2005 11:09 AM
To: Brian McGahan
Cc: ccielab@groupstudy.com; George He; Jim
Subject: RE: 0.0.0.1 on OSPF hello

Hi,

Thanks for the feedback.

Something is not right.

I did this test yesterday and the same 0.0.0.1 appear over other area than 0.

R2 is connected to R5 over multipoint s0/0.257 and to R4 over point-to-point serial 0/0.24
R2--R4 are in area 2.
I made R2--R4 non-broadcast and it also receives hello 0.0.0.1.

Well, there is a virtual link between R2--R4. Maybe this influences the result. What do you think?

Cordially,
------------------------------------------------------------------
Gladston

"Brian McGahan" <bmcgahan@internetworkexpert.com>
04/05/2005 12:05
To
"George He" <georgeh@adstream.com>, "Jim" <nhatquang@thiennam.org>, Alaerte Gladston Vidali/Brazil/IBM@IBMBR, <ccielab@groupstudy.com>
cc

Subject
RE: 0.0.0.1 on OSPF hello

It is just different notation. Area 0.0.0.0 is the same as area
0. Area 0.0.0.1 is the same as area 1.

<RFC 2328>
3.1. The backbone of the Autonomous System

The OSPF backbone is the special OSPF Area 0 (often written as
Area 0.0.0.0, since OSPF Area ID's are typically formatted as IP
addresses). The OSPF backbone always contains all area border
routers. The backbone is responsible for distributing routing
information between non-backbone areas. The backbone must be
contiguous. However, it need not be physically contiguous;
backbone connectivity can be established/maintained through the
configuration of virtual links.
</RFC 2328>

HTH,

Brian McGahan, CCIE #8593
bmcgahan@internetworkexpert.com

Internetwork Expert, Inc.
http://www.InternetworkExpert.com
Toll Free: 877-224-8987 x 705
Outside US: 775-826-4344 x 705
24/7 Support: http://forum.internetworkexpert.com
Live Chat: http://www.internetworkexpert.com/chat/

> -----Original Message-----
> From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf
Of
> George He
> Sent: Wednesday, May 04, 2005 1:54 AM
> To: Jim; gladston@br.ibm.com; ccielab@groupstudy.com
> Subject: RE: 0.0.0.1 on OSPF hello
>
> I remember that if you run OSPF on Windows 2000 box, the area ID like
> 0.0.0.1 or something like this.
>
> Cheers
>
> George
> -----Original Message-----
> From: Jim [mailto:nhatquang@thiennam.org]
> Sent: Wednesday, 4 May 2005 3:32 PM
> To: gladston@br.ibm.com; ccielab@groupstudy.com
> Subject: Re: 0.0.0.1 on OSPF hello
>
> how is the config? it looks like a router-id than an ip address.
>
> ----- Original Message -----
> From: <gladston@br.ibm.com>
> To: <ccielab@groupstudy.com>
> Sent: Wednesday, May 04, 2005 3:55 AM
> Subject: 0.0.0.1 on OSPF hello
>
>
> > Do you know what OSPF means with 0.0.0.1?
> >
> > It is a non-broadcast net, R2 is sending hello to R5. Debug ip ospf
> hello
> > and debug ip packet det are enabled.
> >
> > Send hello to 0.0.0.1
> >
> > Debug ip packet confirms that the destination IP of the hello is
> unicast
> > address. Area is 0.
> >
> >
> > r2#
> > *Mar 1 03:02:11.716: OSPF: Send hello to 0.0.0.1 area 0 on
> Serial0/0.257
> > from 172.16.200.2
> > *Mar 1 03:02:11.716: IP: s=172.16.200.2 (local), d=172.16.200.7
> > (Serial0/0.257), len 124, sending, proto=89
> >
> >
> > When the network is broadcast, it says "Send hello to 224.0.0.5"
which
> > really is the destination IP.
> > But when it is non-broadcast, it seems there is no sense on
"0.0.0.1".
> > (well, I must say, I could not find the sense, hope feedback clarify
> it).
> >
> > r2#sh deb con
> > *Mar 1 03:06:19.834: OSPF: Send hello to 224.0.0.5 area 11 on
> Ethernet0/0
> > from 172.16.26.2
> > *Mar 1 03:06:19.834: OSPF: Send hello to 224.0.0.5 area 11 on
> Ethernet0/1
> > from 172.16.29.2
> >
> >
>



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