RE: PPP over Sonet default MRU

> -----Original Message-----
> From: James Carlson [mailto:james.d.carlson@xxxxxxxxxxxx]
> 6.  LCP Configuration Options
> [...]
>    Design Philosophy
>
> ... and with existing practice.  There are quite a few implementations
> that don't bother implementing every option listed in RFC 1661 (in
> particular, Quality-Protocol is somewhat rare).  None are mandatory.
>

I think we're stuck in semantics.
When negociating Quality Protocol (even if you reject this option), you're NOT negociating your "ability to negociate" link quality monitoring. You're specifying whether you support link quality monitoring or not. Yes link quality monitoring IS optional. Having a MRU however is not a negociable "feature". You may or may not support values other than the default but you can't say I don't support "MRU negociation". Heck just sending a NACK or a REJECT is PART of the negociation. Not that this matters a whole lot, it's just semantics.

> It means "I don't support negotiation of your MRU (my MTU); you'll
> have to live with whatever the default might be, or whatever your
> local configuration tells you to do."

If that ("your MRU is fine") is actually what you wanted to tell the remote end, a simple ACK would have done the trick.

> Obviously, the RFC can't specify a default.  That's not the same thing
> as saying that there *is* no default.

I meant of course that there is no RFC specified default, and I don't know why we are still talking about IPCP.

>
> Basically, if you had a PPP implementation that refused *all*
> configuration options, that would be perfectly legal. 

Sure as long as the link came up using default values.

> > I see your point but it's not a very likely situation. I
> don't see a router
> > removing all possibility of configuring interfaces MTU by
> design just to
> > avoid the possibility of fragmentation.
>
> I think you might be underestimating the perversity of nature.  ;-}

Believe me, I never do at least when it comes to human nature.

>
> I'm not claiming that's what's going on with either of these vendors,
> but it's certainly not an impossible situation.

I never said impossible, just unlikely.

I believe we have definitively exhausted this particular subject.

Thanks again

Steph