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Internet-Drafts | 5 Dec 2007 19:30
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I-D Action:draft-ietf-isis-wg-extlsp-02.txt

A New Internet-Draft is available from the on-line Internet-Drafts directories.
This draft is a work item of the IS-IS for IP Internets Working Group of the IETF.

	Title           : Simplified Extension of LSP Space for IS-IS
	Author(s)       : L. Ginsberg, et al.
	Filename        : draft-ietf-isis-wg-extlsp-02.txt
	Pages           : 16
	Date            : 2007-12-05

This draft describes a simplified method for extending the LSP space
beyond the 256 Link State PDU (LSP) limit defined in [ISO 10589].
This method is intended as a preferred replacement for the method
defined in [RFC 3786].

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http://www.ietf.org/internet-drafts/draft-ietf-isis-wg-extlsp-02.txt

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Radia Perlman | 18 Dec 2007 07:35
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DRB election with two router ports on the same LAN?

I assume IS-IS does the right thing when a router has two ports onto the 
same layer 2 cloud, i.e., the router knows that
they are both the same cloud, and doesn't do something silly like create 
two pseudonodes. I should know this, but it's
been a long time, and hoping someone can trivially answer off the top of 
their head.

                   R1
      port q  /     \ port p
                 |       |
------------------------------

What I'd assume is that R1 would notice if it is receiving its own 
Hellos from port p on port q, and associate the two ports
with being on the same link, and therefore only create a single 
pseudonode. Or to think of it another way, one port would
defer to the other, and R1 would become DR on one port and not on the 
other. But I don't remember a "port number" as
part of the Hello, so there wouldn't be an obvious tie-breaker.

The way the similar thing is done in spanning tree is that the port 
number is part of the priority for being Designated Bridge, and
is included in the Hello, so a bridge
might say "(Root bridge=R, I am cost 7 from R, My ID is B1, My port 
number is p)" and if B1 received this Hello on
another port, the first 3 fields (root ID, cost to root, my ID) would be 
a tie, but the last field (port number) would be
a tie-breaker, so one port naturally defers to the other as if the other 
port won on any of the fields.
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mike shand | 18 Dec 2007 13:02
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Re: DRB election with two router ports on the same LAN?

Radia Perlman wrote:
> I assume IS-IS does the right thing when a router has two ports onto 
> the same layer 2 cloud, i.e., the router knows that
> they are both the same cloud, and doesn't do something silly like 
> create two pseudonodes. I should know this, but it's
> been a long time, and hoping someone can trivially answer off the top 
> of their head.
Yes it does the right thing.
>
>                   R1
>      port q  /     \ port p
>                 |       |
> ------------------------------
>
>
> What I'd assume is that R1 would notice if it is receiving its own 
> Hellos from port p on port q, and associate the two ports
> with being on the same link, and therefore only create a single 
> pseudonode. Or to think of it another way, one port would
> defer to the other, and R1 would become DR on one port and not on the 
> other. But I don't remember a "port number" as
> part of the Hello, so there wouldn't be an obvious tie-breaker.
Yes. The election is by priority and then by MAC address based on what 
you see on the wire and your own information. So as you say, one port 
would defer to the other.

I don't think the standard specifically calls out this case, but that is 
the way it just works. Certainly this worked in the  DEC implementation.

    Mike
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Christian Hopps | 19 Dec 2007 14:47

IETF-70 Meeting Minutes

The minutes from the IETF-70 isis-wg meeting are now available. Thanks  
to Stefano Previdi for taking them.

http://www3.ietf.org/proceedings/07dec/minutes/isis.txt

Chris & Dave.
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Gmane