Subject: draft-ietf-mpls-ldp-mib-08

From: "Hemant P. Kelkar" <[email-masked]>
Date: Sat, 8 Sep 2001 07:52:56 -0400 (EDT)

Hi Everybody,

In draft-ietf-mpls-ldp-mib-08, there is a reference to
"mplsLdpEntityConfGenericLabelRangeTable".
Why is it used for, was not clear. It states that "This table, although
provided as a way to reserve a range of generic labels, does not exist in the LDP
Specification". What does a generic label mean here ?
Second doubt is regarding label distribution: When does an LSR require a
range of labels to distribute ? Can somebody give an example of this sort
of necessity ?

Regards,
Hemant

---

From: Joan Cucchiara <[email-masked]>
Date: Sat, 08 Sep 2001 11:02:14 -0400

Hi Hemant,

> Specification". What does a generic label mean here ?

The LDP specification (rfc 3036) does not discuss
a range for generic labels, where as the LDP spec does call out
using label ranges for ATM (vpi/vci) and Frame Relay (dlci).
This ability to specify (or reserve) a range of generic labels
did make sense for the MIB purposes.  An operator may want this
ability for generic labels also.

Generic labels are labels which would be needed for certain underlying
media,
for example, ethernet or PPP.  Generic labels are  discussed in rfcs
3036 and 3032. 

> range of labels to distribute ? Can somebody give an example of this sort

One example would be that when an LSR (label switch router) wants to
set up an LSP (label switch path) then it needs to negotiate with the
next hop neighbor (peer) and agree upon a range upfront.   When a label
from this agreed upon range is used in the actual LSP setup, 
then there is some level of comfort that the LSP will be setup.  

The MIB provides an operator a way to setup up ranges on the LSR, but
these ranges
still need to be agreed upon (negotiated) between the respective peer
LSR which is part
of the LDP protocol.

  -Joan

---

From: Abhijit Gadgil <[email-masked]>
Date: Mon, 10 Sep 2001 15:02:14 +0530 (IST)

Hemant,

Generic Labels mean Labels which can be used for encapsulating ethernet or
ppp frames. LDP does not specify mechanism of dealing with Label Ranges on
interfaces where one of the above encapsulations is used(Note that this
can be used if you choose so, but then one has to figure out some OOB
mechanisms to distribute and infer them). Label Ranges are specified for a
particular session, if the link between two LSRs is an ATM and Frame Relay
link. Look for rfc3036 for further details. A look at rfc3032 may also
help.

--a

HPK>Hi Everybody,
HPK>
HPK>In draft-ietf-mpls-ldp-mib-08, there is a reference to
HPK>"mplsLdpEntityConfGenericLabelRangeTable".
HPK>Why is it used for, was not clear. It states that "This table, although
HPK>provided as a way to reserve a range of generic labels, does not exist in the LDP
HPK>Specification". What does a generic label mean here ?
HPK>Second doubt is regarding label distribution: When does an LSR require a
HPK>range of labels to distribute ? Can somebody give an example of this sort
HPK>of necessity ?
HPK>
HPK>Regards,
HPK>Hemant
HPK>

-- 
Abhijit Gadgil
Graduate Student,
Dept. of Electrical Engineering,
IIT, Bombay.