RFC 6822, "IS-IS Multi-Instance", December 2012

Note: This RFC has been obsoleted by RFC 8202

Errata ID: 4521
Status: Held for Document Update
Type: Technical
Publication Format(s) : TEXT
Reported By: Alexander Okonnikov
Date Reported: 2015-11-02
Held for Document Update by: Alia Atlas
Date Held: 2015-11-11

Section 2.6.2 says:

   In order for an MI-RTR to interoperate over a point-to-point 
   circuit with a router that does NOT support this extension, the 
   MI-RTR MUST NOT send IS-IS PDUs for instances other than IID #0 
   over the point-to-point circuit as these PDUs may affect the state 
   of IID #0 in the neighbor.

It should say:

   Note: The procedure below should not be used when MI-RTR is 
   operating in point-to-point mode over broadcast circuit 
   [RFC 5309].

   In order for an MI-RTR to interoperate over a point-to-point 
   circuit with a router that does NOT support this extension, the 
   MI-RTR MUST NOT send IS-IS PDUs for instances other than IID #0 
   over the point-to-point circuit as these PDUs may affect the state 
   of IID #0 in the neighbor.

Notes:

In Section 2.6.1, it clearly says "If operating in point-to-point mode on a broadcast circuit [RFC5309]" which reinforces that Section 2.6.2 is about point-to-point circuits and not broadcast circuits.

However, there isn't any harm in adding a bit of clarity going forward. This can be looked at if and when RFC 6822 is updated.

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