1 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt MS-PW Signaling draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Matthew Bocci, Mustapha Aissaoui, Jason Rusmisel, Alcatel Himanshu Shah, Ciena Corp Nabil Bitar, Verizon Yetik Serbest, SBC

2 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Why extend PW control? Reuse existing PW signaling as far as possible –Use a modified form of LDP – Downstream Unsolicited today Lightweight protocol to minimize complexity in U-PE and S-PE LDP already used for L2VPN applications Tunnel and PW signalling are separate issues –PWs are not regular LSPs

3 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Guiding Assumptions Can’t assume U-PEs have full S-PE/U-PE reachability info –Signalling launched by downstream U-PE For PWs, can’t know full path until label mapping has reached T-UPE Informed selection of PW path by upstream U-PE who has service knowledge and view of network path/resources –L2VPN service depends on selection of underlying PW network resources Each hop selects next hop, either: –Controlled path discovery (not flooding) –Blind path search (mandates “crankback”) Crank back to the source vs. Hop-by hop crank back –Requires source routing to be effective, but don’t have full path info Objective is to minimise crank back Same forward and reverse path for OAM Ability to auto-provision backup path

4 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Overview of Solution U-PEs / S-PEs establish T-LDP adjacencies to build PW overlay –U-PEs assume role as active or passive to initiate signaling MS-PW TLV provides unique key to process MS-PW signaling – Peer PW ID: backward compatibility, eliminates need for global PW id MS-PW established through LDP by sending LM to one or more T- LDP peers in succeeding direction –Controlled path discovery enables T-UPE to choose path with full service knowledge (See later slides) –Intelligent choice of next S-PE through local policies, BGP or other topology information –Only TU-PE can retain multiple labels for backup paths –Unused labels at S-PEs are released immediately for already installed FEC –Release unused labels after primary/backup paths selected

5 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt MS-PW Requirements Addressed by Draft Architecture –Enables intra and inter-domain PWs with partial tunnel mesh Resiliency –Tunnel protection with standard PSN mechanisms –S-PE protection Automatically creates a backup path T-UPE can choose a backup path that is disjoint Quality of Service and Class of Service –Supports signaling of PW traffic parameters –Supports forward and reverse CAC at PEs Traffic Engineering –Next hop selection can be based on end to end knowledge (but not mandated) MS-PW Setup Mechanisms. –PW Routing: supports both static and dynamic path selection –Can work in a mixed static / dynamic MS-PW environment Operations and Maintenance (OAM) –Ensures forward/reverse directions take same path –Fully supports existing PW status messaging etc Security –Supports security mechanisms applicable to LDP

6 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Main Changes to PW Control We went with controlled path discovery as opposed to crank-back to source to minimise changes to PW control Needs concept of active/passive U-PE behaviour –Local impact only Needs a few additional TLVs: – MS-PW TLV, QoS TLV Label release if no resources available

7 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Multi Segment PW – Controlled Path Discovery SU-PE TU-PE S-PE:1 S-PE:4 S-PE:2S-PE:3 MS-PW FEC SU-PE does not know best path to TU-PE Downstream Inter-AS

8 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Multi Segment PW - Controlled Path Discovery SU-PE TU-PE S-PE:1 S-PE:4 S-PE:2S-PE:3 Label mapping launched to subset of S-PEs FEC installed Forward/reverse CAC Next hop choice based on: -IP Reachability -Local policy -Static config

9 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Multi Segment PW - Controlled Path Discovery SU-PE TU-PE S-PE:1 S-PE:4 S-PE:2S-PE:3 S-PEs may install one MH-PW FEC if multiple received based on e.g. policy Unused labels released

10 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Multi Segment PW - Controlled Path Discovery SU-PE TU-PE S-PE:1 S-PE:4 S-PE:2S-PE:3 TU-PE makes primary / backup path choice Uses LDP path trace to ensure disjoint paths

11 1/24/2016 draft-shah-bocci-pwe3-ms-pw-signaling-01.txt Multi Segment PW – Controlled Path Discovery SU-PE TU-PE S-PE:1 S-PE:4 S-PE:2S-PE:3 Label mappings launched in reverse directions S-Pes use bindings from MH-PW FEC