Subject: [OSPF] LSInfinity definition

From: Faraz Shamim <[email-masked]>
Date: Wed, 20 Jul 2011 15:30:26 -0500

Hi All,

The early definition of LSInfinity as defined in RFC 1247 is:

LSInfinity
    The link state metric value indicating that the destination is
    unreachable.  It is defined to be the binary value of all ones.  It
    depends on the size of the metric field, which is 16 bits in router
    links advertisements, and 24 bits in both summary and AS external
    links advertisements.

Then we changed it in RFC 1583 as:

LSInfinity
        The metric value indicating that the destination described by a
        link state advertisement is unreachable. Used in summary link
        advertisements and AS external link advertisements as an
        alternative to premature aging (see Section 14.1). It is defined
        to be the 24-bit binary value of all ones: 0xffffff.

The reason for this change was because of E.3 in RC 1583. Then comes RFC
3137 which started using LSInfinity in router link states again:

   o  costs of all non-stub links (links of the types other than 3)
         are set to LSInfinity (16-bit value 0xFFFF, rather than 24-bit
         value 0xFFFFFF used in summary and AS-external LSAs).

So since RFC 3137 is now using LSInfinity for router link states, shouldn't
change the LSInfinity definition back to what it was in RFC 1247? Are there
any plans to revise 2328 in near future?

Faraz

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From: Faraz Shamim <[email-masked]>
Date: Wed, 20 Jul 2011 15:33:20 -0500

Revising the last line in my e-mail:

Since RFC 3137 is now using LSInfinity for router link states, shouldn't WE
change the LSInfinity definition back to what it was in RFC 1247? Are there
any plans to revise 2328 in near future?

From:  Microsoft Office User <[email-masked]>
Date:  Wed, 20 Jul 2011 15:30:26 -0500
To:  <[email-masked]>
Subject:  LSInfinity definition

Hi All,

LSInfinity

LSInfinity

Faraz

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From: Acee Lindem <[email-masked]>
Date: Wed, 20 Jul 2011 16:38:07 -0400

Hi Faraz,

On Jul 20, 2011, at 4:33 PM, Faraz Shamim wrote:

> Since RFC 3137 is now using LSInfinity for router link states, shouldn't WE change the LSInfinity definition back to what it was in RFC 1247?

I don't understand since the LSInfinity is a 24-bit value and the link cost is only 16 bits. 

> Are there any plans to revise 2328 in near future?

No - it is actually one of the few Routing Area documents which has reached full standard. 

Thanks,
Acee 

> The reason for this change was because of E.3 in RC 1583. Then comes RFC 3137 which started using LSInfinity in router link states again:
> 
> So since RFC 3137 is now using LSInfinity for router link states, shouldn't change the LSInfinity definition back to what it was in RFC 1247? Are there any plans to revise 2328 in near future?
> 
> Faraz
> 
> 
> _______________________________________________
> OSPF mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/ospf

---

From: Acee Lindem <[email-masked]>
Date: Wed, 20 Jul 2011 18:46:04 -0400

Hi Faraz, 

Ok - now I understand. We will fix the incorrect terminology in the RFC 3137 Bis draft. It should not refer to LSInfinity as this is not an infinite metric. It simply discourages transit traffic.  

Thanks,
Acee