RE: Q: is framing-capabilities value=0 legal

At 09:22 11/1/2005 -0800, Ricky Charlet wrote:
>	I hope I paraphrase your response correctly to say that Fr-cap=0
>is allowable and its meaning is "I will not initiate", and it may even
>be common from an LNS.
>
>
>	But even if I see your meaning correctly, that still does not
>help me in my situation. I'm the LNS, and I am receiving Fr-Cap=0 from
>the LAC. The LAC I am dealing with has an obvious bug in that it's
>Fr-Cap setting is configurable but it ignores the configuration and
>always sends 0. Yet still, this is a popular LAC and I want to
>interoperate with it.
>
>	From my LNS's perspective... should I be generous in what I
>accept, or is there a reason I must abort the connection?


The question you have to ask yourself is what do you gain by being
picky on something inconsequential.

Remember that L2TP (even 2661) is symmetrical: the role of LNS or
LAC is a per-call role, not a per-tunnel role. By sending framing
capabilities == 0, the L2TP peer is promising that it won't send
an OCRQ. From your point of view, why is that a problem to you?

If the remote's promise of never send an OCRQ is not a problem
to you (and, if your product is only an LNS, it shouldn't be),
ask yourself why reject the tunnel?

By all means, I strongly suggest that you should follow Jon Postel's
principle of robustness (RFC793, section 2.10): be conservative in
what you send and liberal in what you accept from others.

Unless something really affects your functionality, what's the harm
in accepting it?