From: ccamp-bounces at ietf.org [mailto:ccamp-bounces at ietf.org] On Behalf Of choudarypally.subramanyam at wipro.com
Sent: Thursday, October 22, 2009 1:51 AM
To: ccamp at ietf.org
Subject: [CCAMP] draft-ietf-ccamp-gmpls-ethernet-pbb-te-03.txt- regardingISID error handlingHi ,
I am currently working on draft “draft-ietf-ccamp-gmpls-ethernet-pbb-te-03.txt” and I write this email to seek some help from experts. I have two questions regarding the Section 3 paragraph 6.
1) It say “An IB-BEB receiving a PATH message specifying one
of its CNPs can locally determine which CBPs have internal
connectivity to the I-component supporting the given CNP.”How does the CSPF function select egress CNP, based on what criteria?
The CNP is the port to which clients of the PBB-TE domain are connected to. CSPF should consider which clients the Eth-LSP is meant to support.
[Choudarypally] I will try to rephrase the question, What should the constraints be for the ingress CSPF to correctly identify the egress CNP while creating the PATH message? As I understand the CSPF will ONLY have the complete PNP links and CNP TE links database, but ingress CSPF will not know about the ISID to CNP mappings on the egress. In which case ingress CSPF will not be able to identify the clients meant for Eth-LSP.
2) Further it says “On the other hand, if there is information on
the service (I-SID) that the given ESP will support, then the IB-BEB
MUST first determine which PIP and CBP is configured with the I-SID
and MUST assign that CBP to the ESP”a) What should be action taken if ISID received in PATH message is not configured? Do I need to send PATH ERR message?
Then the ISID should be "dynamically" configured to an appropriate CBP that is connected to the CNP.
[Choudarypally] As I understand the ISIDs should be created by provider based on the agreement with the customer. Not sure if the ISIDs can be created dynamically based on signaling. Please let me know what you think about this.
b) Assuming that I have received more than one ISID and each one belong to different CBP port, in such case what should be the behavior?
This should not happen provided the path computation and the service (ISID) allocation is done properly.
In case it would happen, one can try to reconfigure the CBP ISID allocations on the egress, if this is not possible then an error should be raised and sent in Path_Err. I couldn't find a good error value for this on the registry, if we want to account for this case explicitly we possibly need a new error value Routing Problem / Invalid Service ID
[Choudarypally] I agree that this should not happen but in case the ISID to CBP mapping on egress (which is done manually by operator based on service agreement) is misconfigured. So the dynamic reconfiguration of ISID to CBP may not be a good option. Ideally a PATH ERR should be generated with appropriate error code.
I am doing the manual configuration and association of ISID to CBP.
Regards
Choudarypally