Subject: Questions in "draft-katz-yeung-ospf-traffic-01.txt"

From: Ghassen Benbrahim <[email-masked]>
Date: Fri, 10 Mar 2000 14:16:42 -0600 (CST)

Hello everybody,

I have 2 questions in the draft "Traffic Engineering Extension to OSPF"
(draft-katz-yeung-ospf-traffic-01.txt) :

* Question 1: This question relates to the metric sub-TLV

section 2.5.5 (Traffic Engineering Metric)

type = 5
length = 4 octets
What is in the value field ?

is it the administrative weight ?

Also I do not see how it (this sub-TLV) relates to the other metric fields
that have been defined in sections 2.5.6, 2.5.7. etc

* Question 2: relates to the 8 priority levels

section 2.5.8
are these priorities the same as the one expressed by the EXP
field in the MPLS label.?

If no, would you please provide with more explanation..

Any clarification on these points will be greately appreciated.

Thanks

Sincerely,

--Ben

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From: Quaizar Vohra <[email-masked]>
Date: Fri, 10 Mar 2000 16:42:14 -0800 (PST)

Traffic engineering metric is to constrained shortest path first what a
link metric is to shortest path first. It is a 32 bit integer which
one assigns to the link for TE purpose, i.e. for use by constrained
shortest path first or some such algorithm. Its a value a network
admin assigns to a link (very similar to how a link metric is 
assigned in routing protocols).

No the priorities are not related to the EXP field in an MPLS label.
The meaning of priorities in the TE context is explained in RFC 2702
(Requirements for Traffic Engineering over MPLS).

Quaizar

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From: Quaizar Vohra <[email-masked]>
Date: Fri, 10 Mar 2000 16:49:31 -0800 (PST)

Offcourse, this metric is used by CSPF (or something similar) as one of 
the constraints in addition to available b/w constraints, colors etc.