Label_Set and Channel_Set in draft-ietf-ccamp-gmpls-dcsc-channel-ext-01.txt
Remi Theillaud <remi.theillaud@marben-products.com> Tue, 31 March 2009 10:32 UTC
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From: Remi Theillaud <remi.theillaud@marben-products.com>
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Subject: Label_Set and Channel_Set in draft-ietf-ccamp-gmpls-dcsc-channel-ext-01.txt
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One question about a Label_Set containing Channel_Set labels: Let's consider the following LABEL_SET object. Labels are assumed to be two bytes Generalized labels (type 2) - such as the EVPL Generalized Label format defined in draft-ietf-ccamp-gmpls-ether-svcs-03.txt. 0 1 2 3 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Length | Class-Num (36)| C-Type (1) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Action(0) | Reserved | Label Type(4) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Action(2) |Num Subchannels(2) | Label Type(2) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subchannel 1(100) | Subchannel 2(200) | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Action(2) |Num Subchannels(2) | Label Type(2) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Subchannel 1(300) | Subchannel 2(400) | |-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ I can see two different interpretation of this LABEL_SET: 1. This LABEL_SET specifies a single subchannel, which uses the format of a Channel_Set label.The Channel_Set label consists of two ranges: 100..200 and 300..400. The purpose of this LABEL_SET would be to force the downstream node to send back a LABEL object that consists of range 100..200 AND range 300..400. 2. This LABEL_SET specifies two subchannels, both using the format of a Channel_Set label. The first channel is the range 100..200; the second one is the range 300..400. The purpose of this LABEL_SET would be to force the downstream node to send back a LABEL object that consists either of range 100..200 OR range 300..400 Which interpretation is the correct one? am I misunderstanding something? One way to remove the ambiguity would be to consider that the LABEL_SET object can contain only one Channel_Set label (case 1 is then the correct interpretation). And it would be possible (if needed) to handle case 2 by using two LABEL_SET objects in a Path message. Rémi
- Label_Set and Channel_Set in draft-ietf-ccamp-gmp… Remi Theillaud