1. Geneva, Switzerland, 13 July 2013 Multipoint Ethernet Connection Protection (MECP) Taesik Cheung Principal Researcher ETRI Joint IEEE-SA and ITU Workshop on Ethernet

2. Geneva, Switzerland, 2 13 July 2013 2 MECP Overview MECP is a study point of Q9/WP3. Scope of MECP is to protect single rooted- multipoint (RMP) Ethernet connections in Ethernet transport networks. Contributions have been provided for a mechanism based on G.8031 APS protocol to support 1+1 and 1:1 protection Per-tree and per-leaf protection

3. Geneva, Switzerland, 2 13 July 2013 3 Problem Statements G.8031 (APS) or G.8032 (R-APS) can be used between root and each leaf node. Root node should process multiple (R)-APS instances. Leaf 1Leaf 2Leaf 3Leaf n Root Switch Leaf 1Leaf 2Leaf 3Leaf n Root n x R-APS instances Switch n x APS instances X In case of a failure affecting many leaf nodes, there may be a need for many (R)-APS instances to switch-over simultaneously.

4. Geneva, Switzerland, 2 13 July 2013 4 Use Cases of MECP MECP could be used to protect RMP connections in a tree network topology. Potential use cases: Mobile backhaul networks Administrative networks of provincial government (Connection between leaf nodes is not allowed.) DU(1)DU(2)DU(3)DU(m) PTS Working tree Protection tree Aggr. Single MECP instance PTS: Packet Transport Switch, Aggr.: Aggregation switch, DU: Digital Unit

5. Geneva, Switzerland, 2 13 July 2013 5 Per-tree Protection A working tree is protected by a dedicated protection tree. R L1 L2 Lm R L1 L2 Lm X Working tree Protection tree Working tree Protection tree A single failure on the working tree which affects only a portion of the leaf nodes causes the whole traffic flowing on the working tree to be switched to the protection tree.

6. Geneva, Switzerland, 2 13 July 2013 6 Per-leaf Protection A working tree is protected by a dedicated protection tree. R L1 L2 Lm R L1 L2 Lm X Working tree Protection tree Working tree Protection tree In the event of a failure on the working tree, per- leaf protection switches over the traffic that belongs to the affected leaf node.

7. Geneva, Switzerland, 2 13 July 2013 7 A proposal to base MECP protocol on G.8031 Working P2P EC Protection P2P EC West nodeEast node B S S B APS NR(0,0) SF detected on working path SF(1,1) Set bridge/selector to protection path Send request Set bridge/selector to protection path NR(1,1) Send confirmation Accept request B: Bridge S: Selector 1-phase APS Protocol

8. Geneva, Switzerland, 2 13 July 2013 8 Per-tree protection architecture Working RMP EC Protection RMP EC Root nodeLeaf node (1) B S S B APS(R) APS(L1) Leaf node (2) S B APS(L2) Leaf node (m) S B APS(Lm) Root node has one bridge and one selector. Each leaf node has one bridge and one selector. Root node sends identical APS messages to all the leaf nodes. (using multicast DA) Each leaf node sends APS messages to the root node.

9. Geneva, Switzerland, 2 13 July 2013 9 Per-leaf protection architecture Working RMP EC Protection RMP EC Root nodeLeaf node (1) B S S B APS(R) APS(L1) Leaf node (2) S B APS(L2) Leaf node (m) S B APS(Lm) Root node has one broadcast bridge and multiple selectors. Each leaf node has one bridge and one selector. Root node sends different APS messages to each leaf nodes. (using unicast DA) Each leaf node sends APS messages to the root node. N W P Broadcast bridge N W P Selector bridge Wr W1~Wm Pr P1~Pm Wr: Working tree (root  all leaves) Pr: Protection tree (root  all leaves) Wm: Working path (leaf m  root) Pm: Protection path (leaf m  root)

10. Geneva, Switzerland, 2 13 July 2013 10 Issues under discussion Architecture and mechanism for per-leaf protection Consideration on various triggers for per-tree protection Benefits of per-tree protection comparing with per-leaf protection Monitoring methods for working/protection tree Trade-off in terms of processing/management of per-tree protection vs. using N APS/R-APS processes