SPCs

[John Drake <jdrake@calient.net>]

I thought it might be useful to see what RFC3474 actually says about SPCs:

"The processing of the SPC_LABEL sub-object follows that of the
   EGRESS_LABEL sub-object [OIF-UNI1].  Note that although the explicit
   label control described in [RFC3471] and [RFC3473] may provide a
   mechanism to support specifying the egress label in the context of
   supporting the GMPLS application, the SPC services support for the
   ASON model uses the GENERALIZED_UNI object for this extension to help
   align the model for both switched connection and soft permanent
   connection, as well as to use the service level and diversity
   attributes of the GENERALIZED_UNI object."

A few observations:

1)  I don't think any clarifications to RFC3471/3473 wrt egress node
explicit label
control are required.  If the authors of RFC3474 can figure out the correct
behavior,
I'm sure anyone else can.

2)  Any divergence between RFC3471/3473 and RFC3474 is clearly the
responsibility
of the authors of RFC3474.

3)  'call' vs 'connection' is not cited as one of the reasons for this
divergence.
In fact, once again 'connection' is used in the text.  (I'm not surprised,
as the
GENERALIZED_UNI object was defined in OIF UNI 1.0, which doesn't support
calls.)

4)  The diversity attribute is completely useless in the multi-domain case,
since
it is a list of connections within the context of a specific UNI.  No border
node
is going to have any way to identify those connections or determine how they
are
routed.

5)  I thought "the SPC services support for the ASON model uses the
GENERALIZED_UNI
object" was rather imperious.  It's pretty clear that the GENERALIZED_UNI
object
is not required by the ASON model.
 
Thanks,

John

John Drake
Calient Networks
5853 Rue Ferrari
San Jose, CA 95138
jdrake@calient.net
408 972-3720