Multipoint Ethernet Connection Protection (MECP)

Geneva, Switzerland, 13 July 2013

Multipoint Ethernet ConnectionProtection (MECP)

Taesik CheungPrincipal Researcher

ETRI

Joint IEEE-SA and ITU Workshop on Ethernet

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 protectionPer-tree and per-leaf protection

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 1 Leaf 2 Leaf 3 Leaf n

Root

Switch Switch

Leaf 1 Leaf 2 Leaf 3 Leaf n

Root n x R-APSinstances

Switch Switch

n x APSinstances

X

In case of a failure affecting many leaf nodes, there may be a need for many (R)-APS instances to switch-over simultaneously.

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 networksAdministrative networks of provincial government (Connection between leaf nodes is not allowed.)

DU(1) DU(2) DU(3) DU(m)

PTS

Workingtree

Protectiontree

Aggr. Aggr.

Single MECPinstance

PTS: Packet Transport Switch, Aggr.: Aggregation switch, DU: Digital Unit

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.

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.

Geneva, Switzerland, 2 13 July 2013 7

A proposal tobase MECP protocol on G.8031

Working P2P EC

Protection P2P EC

West node East node

B

S

S

BAPS

APS

NR(0,0) NR(0,0)

SF detected on working path

SF(1,1)

Set bridge/selector to protection path

Send request

Set bridge/selector toprotection path

NR(1,1)Send confirmation

Accept request

B: BridgeS: Selector

1-phase APS Protocol

Geneva, Switzerland, 2 13 July 2013 8

Per-tree protection architecture

Work

ing

RM

P E

C

Pro

tecti

on

RM

P E

C

Root node Leaf node (1)

B

S

S

BAPS(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.

Geneva, Switzerland, 2 13 July 2013 9

Per-leaf protection architecture

Work

ing

RM

P E

C

Pro

tecti

on

RM

P E

C

Root node Leaf node (1)

B

S

S

BAPS(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.

NW

PBroadcast bridge

N W

PSelector 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)

Geneva, Switzerland, 2 13 July 2013 10

Issues under discussion

Architecture and mechanism for per-leaf protectionConsideration on various triggers for per-tree protectionBenefits of per-tree protection comparing with per-leaf protectionMonitoring methods for working/protection treeTrade-off in terms of processing/management of per-tree protection vs. using N APS/R-APS processes