The MPLS WG Archive

[Leonardo Balliache <lbb@opalsoft.net>]

Eric,

At 10:29 p.m. 19-10-2004 -0400, you wrote:
>Leonardo,
>
>    Let me see if I understand you.  You're asking me to review your code?
>
>    :-)  (-:   :-)  (-:   :-)

No, absolutely not. I thought the code could help to clear my question, but 
it is evident that it was a very bad idea.

>    Try breaking this into steps and ask about the steps that aren't clear. So
>far, you've copied a section out of the appendix (twice) and said that you
>don't understand it.  Please be specific as to what it is you don't 
>understand. Trying to make sense out of your code fragment - which is 
>clearly not 100%
>exactly congruent with the procedural steps and is out of context as well -
>just gives me a huge headache.

Sorry if I've bother you some way.


>    The reason why the procedure is not meant to be pseudo code is that
>it describes what it is that the implementation is supposed to do. There is
>no strict ordering or contextual mapping of the things your implementation
>has to do to the way in which your implementation does them.  If you take
>a broad look at how many ways there are to do the rest of the things that
>any label switching implementation might do, you will quickly realize how
>pointless it would be to try to cover all the ways in which this particular
>set of "steps" might be done.

I agree, but perhaps the specification shouldn't be so specific. Working 
and revising the spec and coding it I have realized that you are right. 
Many questions are answered when one understand better the LDP logic.

Talking about "Recognize New FECs", I insist that:

1.- In "unsolicited independent control" function 
"prepare_label_mapping_attribute" is called. This function requires the 
argument "propagating_" which is set (before calling the function) to true 
if the LSR has received previously a label mapping for fec from nexthop. It 
is set to false otherwise.

2.- In "unsolicited ordered control" the function "prepare_label_mapping" 
is also called. But this time the argument it needs (propagating_) is not 
previously set. Can I suppose that it should be false if the LSR is the 
egress for that fec and true if the LSR has received previously a label 
mapping for fec from nexthop?

>    As for PMpA.14 - it asks if there _is_ a hop count. For that purpose,
>it is irrelevant whether it is the incremented or unincremented value. In any
>case, I believe you understand the gist of that section.

You are right, this is clear.

>--
>Eric

Best regards,

Leonardo Balliache



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