Clarification on contents of Label Set object

[Ashok Narayanan <ashokn@cisco.com>]

Folks,

We are seeking clarification with regards to the label values to be
included in a Label-Set object and Accetable-Label-Set object.

In general, it is possible for a data-link using LSC or FSC switching
to have different label values on either side of the link.  The two
sides must agree on which side does the mapping: the object sender or
the object receiver.

For the case of sending Label-Set/Acceptable-Label-Set, rfc3473 does
not state explicitly whether the labels in the object should be from
the the point of view of the object sender or object receiver of the
object.

Our conclusion based on RFC3471, Section 3.2.1.1 is that the labels
always reflect the object sender's point of view and are mapped by the
object receiver.  For instance, in the case that an upstream node is
including a Label-Set in a Path message, the labels included should be
from the space of labels used by the upstream node, and the downstream
node translate them before selecting one. Correspondingly, when a
PathError message carries an Acceptable-Label-Set, the receiver of the
PathError message (the upstream node) would first translate the
elements before selecting one.

Are there any alternate views?

Thanks
-Ashok

--- Asok the Intern ----------------------------------------
Ashok Narayanan
IOS Network Protocols, Cisco Systems
1414 Mass Ave, Boxborough MA 01719
Ph: 978-936-1608.  Fax: 978-936-2218 (Attn: Ashok Narayanan)