Subject: Handling Label Objects in RESV messages

From: Arumugam R <[email-masked]>
Date: Mon, 25 Sep 2000 15:36:38 +0530

Hi,
Sorry for revisiting the topic.
 There are some issues related to rechecking procedure dealt between 
section 4.1.1.1 and section 4.1.1.2 1.
Q.no 1
section 4.1.1.1
The downstream node selects a label to represent the flow. If a label range 
has been specified in the label request, the label must be drawn from that 
range. If no label is available the node sends a PathErr message with an 
error code of "routing problem" and an error value of "label allocation 
failure".
section 4.1.1.2
3rd case :- The assigned label is outside the requested label range
In any of these events the node send a ResvErr message with an error code 
of "routing problem" and an error value of "unacceptable label value".
The argument is  section 4.1.1.1 says label MUST be drawn from the range, 
else send path err towards the sender. Isn't the node conforming to this 
will return a valid label ?  Is there the necessity to recheck the label 
and send a ResvErr.
 Q.no 2
section 4.1.1.1
 In the case of ATM, one further condition applies. Some ATM nodes are not 
capable of merging streams. These nodes may indicate this by setting a bit 
in the label request. The M-bit in the LABEL_REQUEST object of C-Type 2, 
label request with ATM label range, serves this purpose. The M-bit SHOULD 
be set by nodes which are merge capable. If for any senders the M-bit is 
not set, the downstream node MUST assign unique labels to those senders.
section 4.1.1.2
1st case . The node is a merge incapable ATM switch but the downstream node 
has assigned the same label to two senders
The same argument is valid here too.
As per the draft once the node is conforming to section 4.1.1.1, rechecking 
the assigned values in section 4.1.1.2 is purely a overhead.
 Comments are welcome from the authors for inclusion of new error values 
for these two cases.
Thanks in advance
Regards
Arumugam
------------------------------------------------------------------------  
--------
Arumugam R
Senior Software Engineer,
Team Member ( MPLS Product Development Group)
Future Software Ltd.
Chennai - 35
Fone-4330550 Ext-332
------------------------------------------------------------------------  
--------