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Futher clarification needed-- Un-numbered point to point. doubt
Hi,
Thanks to all of u for ur valuable inputs. Now, i need some specific
clarification..
Lets assume the following is the topoly:
R1 R2
____ ___
O----| ___|------------|___|------O
E1 I1 I2 E2
The topology detail:
1) R1 and R2 are two routers.
2) E1 is ethernet and I1 is un-numbered p2p interface of R1.
3) Similarly E2 is ethernet and I2 is un-numbered p2p interface of R2.
4) Assume E1 is 192.168.12.1 (mask is 255.255.255.0)
5) Assume E2 is 192.168.13.1 (mask is 255.255.255.0)
6) Now as per RFC 1812 (un-numbered p2p support at IP), the interface I1 of
R1 will borrow the IP address of E1 (192.168.12.1) and similarly I2 of R2
borrow the IP address of E2 (192.168.13.1) to specify the source address in
the IP header.
7) Lets assume as per my stack implementation, OSPF uses RAW socket with IP
header inclusion option, for the OSPF packet sending out. In this case, IP
forward/trasmit will receive OSPF packet (Lets say Hello) and IP header with
source as 192.168.12.1 and destination as Multicast address 224.0.0.5.
Case 1:
8) IP will look into the route table to send the packet, obviously it could
not find anything match for this detination, then either it may discard or
just forward the packet to defualt destination (or gateway). In our case it
is more probably the Lan interface. So in this case there is no chance of
OSPF packet to be sent over the Un-numbered point to point interface.
Case 2: If the above problem is because of using RAW socket, and will it be
solved, if OSPF explicity specifies the interface Name/index through which
the OSPF packet need to delivered, then IP will deliver it in the right
interface??
Clarification 2: My other question is: do i need to specify the neighbor
(other end of the interface) IP address, when i configure the Numbered point
to point for OSPF??
Thanks in advance,
GKS
NEC America,
CA USA.
----- Original Message -----
From: "klara moser" <klara.moser at alcatel.com>
To: <OSPF at discuss.microsoft.com>
Sent: Thursday, March 06, 2003 9:16 AM
Subject: Re: Un-numbered point to point. doubt
> Thanks Acee,
>
> It is a broadcast address from OSPF protocol point of view, this is why I
called it
> "broadcast" :)
>
> Klara
>
> Acee Lindem wrote:
>
> > Klara,
> >
> > Just one clarification - AllSPFRouters (224.0.0.5) is
> > a local-wire multicast address. I know this is what you meant but
> > wanted to avoid confusion.
> >
> > klara moser wrote:
> > ? Hi GKS,
> > ?
> > ? Actually, on a un-numbered point-to-point interface OSPF will send
all its
> > ? packets to the well defined All OSPF Routers "broadcast" address. In
this case
> > ? you do not need a uniquely defined IP address for the remote peer. The
only
> > ? requirement is that the layer two supports the OSPF "broadcast"
address.
> > ?
> > ? Greetings
> > ? Klara
> > ?
> > ? "Farshad (Sean) Tavallaei" wrote:
> > ?
> > ?
> > ??GKS,
> > ??
> > ??Also, RFC 1586 section 3.2 is a good place to look at. Remember, the
virtual
> > ??links are like the unnumbered links for OSPF.
> > ?
> > ?
> > ? Except for the virtual link you need the peer address, for unnumbered
> > ? point-to-point interface you don't.
> > ?
> > ?
> > ??From what I understand, when
> > ??sending an OSPF packet through a virtual link, you need to know the
> > ??destination IP address, which is supposed to be one of the interface
IP
> > ??addresses of the remote ABR. If the remote ABR is connected through
> > ??unnumbered links only, you may not know any of its IP addresses. You
may try
> > ??to use looking for a /32 in the router-LSA and using it as the dst if
no
> > ??interface addresses are available, however, there may be situations
where
> > ??this is just not possible (i.e., no loopback addresses are announced).
> > ??
> > ??draft-ietf-isis-igp-p2p-over-lan-00.txt also has some good pointers.
> > ??
> > ??Hope that helps,
> > ??
> > ??Farshad
> > ??
> > ??-----Original Message-----
> > ??From: Farshad (Sean) Tavallaei [mailto:farshad at onebox.com]
> > ??Sent: Wednesday, March 05, 2003 6:51 PM
> > ??To: Mailing List
> > ??Subject: RE: Un-numbered point to point. doubt
> > ??
> > ??GKS,
> > ??
> > ??RFC 1812 section 2.2.7 is a good start. I think I have seen this done
with
> > ??Linux using virtual or logical IP addresses or interfaces, or even
sometimes
> > ??loopback addresses for the unnumbered IP address.
> > ??
> > ??I know that may not be much, but it is a start.
> > ??
> > ??Good luck,
> > ??
> > ??Farshad
> > ??
> > ??-----Original Message-----
> > ??From: Mailing List [mailto:OSPF at DISCUSS.MICROSOFT.COM]On Behalf Of
kamatchi
> > ??soundaram
> > ??Sent: Wednesday, March 05, 2003 11:00 AM
> > ??To: OSPF at DISCUSS.MICROSOFT.COM
> > ??Subject: Un-numbered point to point. doubt
> > ??
> > ??Hello all!,
> > ??
> > ?? I presently working on OSPF un-numbered point to point support. I
need
> > ??some clarification in implementing this support..
> > ??
> > ??Well! to support this un-numbered point to point, the IP need to
support
> > ??this feature. If some body put some light on this it will be great!
Yes!
> > ??even if get some general view about how the IP need to support the
> > ??un-numbered point to point of OSPF??
> > ??
> > ?? Is there any standard available for this??
> > ??
> > ??Well! what i know is:
> > ??* in case of un-numbered point to point, the one of valid IP address
of
> > ??other interface will be assigned to this un-numbered p2p. So, that
whenever
> > ??OSPF sends the packet, it will use this IP address as source address
in the
> > ??IP header. But how exactly it is implemeted?? Especially in linux kind
of
> > ??IP. (and stack).
> > ??
> > ??Thanks,
> > ??GKS.
> > ??NEC america,
> > ??CA.
> > ?
> > ?
> >
> > --
> > Acee
>