Re: [Isis-wg] Alvaro Retana's No Objection on draft-ietf-isis-auto-conf-04: (with COMMENT)

"Alvaro Retana (aretana)" <> Fri, 07 April 2017 21:25 UTC

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From: "Alvaro Retana (aretana)" <>
To: "Les Ginsberg (ginsberg)" <>, The IESG <>
CC: "" <>, Hannes Gredler <>, "" <>, "" <>
Thread-Topic: Alvaro Retana's No Objection on draft-ietf-isis-auto-conf-04: (with COMMENT)
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Subject: Re: [Isis-wg] Alvaro Retana's No Objection on draft-ietf-isis-auto-conf-04: (with COMMENT)
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On 4/7/17, 5:09 PM, "Les Ginsberg (ginsberg)" <> wrote:



> > (2) What about the other bits in the Flag field, how should they be registered
> > in the future (if needed)?  Please ask IANA to define a registry for them.
> > 
> [Les:] I don't think a registry is needed. If an additional flag is required then a bis 
> draft will be required.

No.  That’s the point of specifying how others may request a flag in a registry: then they can go to IANA and not touch your document.

If I try to read between the lines…it sounds like you’re saying that the TLV would have no other use than for auto-configuration, so if any new flag is to be assigned it would necessarily have to modify this document.  Is that what you mean?

Honestly, I think it is just good practice to define how the remaining bits should be assigned/or not in the future.  But I’ll let the responsible AD make the call. ;-)

> > (5) I thought the point of this document was for use in "unmanaged
> > deployments.  It allows IS-IS to be used without the need for any
> > configuration by the user."  But Section 3.5. (Additional IS-IS TLVs Usage
> > Guidelines) has recommendations for configuration options, including
> > manually configured adjacencies (which should not be allowed according to
> > Section 3.4.2. (Adjacency Formation)).  Isn't this against the stated reasons
> > for this document?
> > 
> [Les:] The mention of "manually configured adjacencies" is in the context of what 
> the default metric should be for non-manual adjacencies.
> We do not recommend manual configuration, but it is not illegal to do it.

Would manual configuration unset the A flag because now the node is not acting in auto-configuration mode?   

I know some of this was discussed on the list before, but if partial manual configuration is allowed (and the A flag is still set), what prevents a manually configured router from setting the A flag and if the parameters (area, level, etc.) match, form an adjacency?  There was a discussion about not allowing non-auto-configured routers and auto-configured ones from becoming adjacent.

> > (6) Authentication is one of those features that could be manually configured
> > -- but the default is no authentication.  There's a higher-than-usual risk of a
> > node listening on the network (probably a bigger problem for the user
> > traffic), but also one that could listen to the Hellos and purposefully trigger
> > the duplicate resolution mechanism to continuously run.  This risk should be
> > highlighted in the Security Considerations because it is newly introduced
> > here. [Robert Sparks pointed this risk out during his GenArt review.]
> >
> [Les:] Let me know if the answer I provided to Robert suffices.

No.  I would have the same answer that he did: you should describe the new risk.  But let’s keep the discussion on that thread.