1. IETF 69, July 2007Slide 1 Preferential Forwarding Status bit Definition draft-muley-dutta-pwe3-redundancy-bit-01.txt Praveen Muley, Pranjal K. Dutta, Mustapha Aïssaoui, Marc Lasserre, Matthew Bocci, Alcatel-Lucent Jonathan Newton, Cable & Wireless Olen Stokes, Extreme Networks Hamid Ould-Brahim, Nortel Networks Luca Martini, Cisco Systems

2. IETF 69, July 2007Slide 2 Updates from Version 00 1.Added a new contributor to the author list 2.Expanded on the motivation of the new proposed status bit and explained why the already defined operational status bits are not sufficient 3.Added a separate definition of the active and standby PW states for the Independent mode and for the Active/Standby Mode 4.Enforced the rule that an endpoint MUST not forward user packets over a PW which is in standby mode 5.Removed the option to send the 'PW not forwarding' status bit In Master/Slave mode if the slave could not unblock the PW 6.Added an applicability and backward compatibility section 7.Removed reference to the LDP specification in the security section which now refers to RFC 4447 only

3. IETF 69, July 2007Slide 3 Active state definition in Independent Mode A PW is considered to be in Active state when: –the PW labels are exchanged between its two endpoints in control plane, and –the status bits exchanged between the endpoints indicate the PW is UP and Active at both endpoints In this state data traffic can flow over the PW in both directions

4. IETF 69, July 2007Slide 4 Standby state definition in Independent Mode A PW is considered to be in Standby state when: –the PW labels are exchanged between its two endpoints in the control plane, and –the status bits exchanged indicate the PW is in Standby state at one or both endpoints In this state the endpoints MUST NOT forward data traffic over the PW but MAY allow PW OAM packets, e.g., VCCV, to be sent and received in order to test the liveliness of standby PW

5. IETF 69, July 2007Slide 5 Active state definition in Master/Slave Mode A PW is considered to be in Active state when: –the PW labels are exchanged between its two endpoints in control plane, and –the status bits exchanged between the endpoints indicate the PW is UP at both endpoints, and –the forwarding status sent by the Master endpoint indicates Active state In this state data traffic can flow over the PW in both directions

6. IETF 69, July 2007Slide 6 Standby state definition in Master/Slave Mode A PW is considered to be in Standby state when: –the PW labels are exchanged between its two endpoints in the control plane, and –the status bits sent by the Master endpoint indicate the PW is in Standby state In this state the endpoints MUST NOT forward data traffic over the PW but MAY allow PW OAM packets, e.g., VCCV, to be sent and received in order to test the liveliness of standby PW

7. IETF 69, July 2007Slide 7 Interoperability with existing implementations A T-PE/PE which does not implement the new active/standby status bit keeps a PW active as long as it is operationally up –It does not actively block forwarding over a PW –It does not act on active/standby status bit received from peers For the operation of the VPWS and VPLS redundancy applications, all participating T-PE/PE nodes MUST implement the appropriate mode (independent or master/slave)

8. IETF 69, July 2007Slide 8 Applicability and Backward Compatibility The mechanisms defined in this document are OPTIONAL and are used in PWE3 applications where standby state signaling of PW/PW group is required PE implementation compliant to this document –It MUST negotiate the use of PW status TLV between its T-LDP peers as per RFC 4447 –If PW Status TLV is found to be not supported by either of its endpoint after status negotiation procedures, then the mechanisms specified in this document cannot be used PE implementation compliant to RFC 4447 and which does not support the generation or processing of the active/standby status bit –will not set this bit in the status bits transmitted to a peer PE, and –will not examine it in the received status bits from a peer PE –The mechanisms specified in this document cannot be used

9. IETF 69, July 2007Slide 9 Next Step Authors are investigating a potential enhancement to Master/Slave mode which will make use of two bits instead of one –‘Request switchover’ bit, and –‘Actual PW active/standby state’ status bit at each PE Authors would like to request WG feedback on mailing list