draftzhlmplstpsd01txt H Zhang J He Huawei H Li CMCC IETF 76th meeting Hiroshima November 2009 Requirements In draftietfmplstpsurvivefwk02 Section 412 FailureTriggered Actions Survivability actions may be directly triggered by network failuresfailure is ID: 284979
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SD-Triggered Protection Switching in MPLS-TPdraft-zhl-mpls-tp-sd-01.txt
H. Zhang, J. He, HuaweiH. Li, CMCC
IETF 76th meeting – Hiroshima, November 2009Slide2
RequirementsIn draft-ietf-mpls-tp-survive-fwk-02Section 4.1.2. Failure-Triggered Actions: “Survivability actions may be directly triggered by network failures……"failure" is used to represent both signal failure and signal degradation”
This document describes Signal Degrade (SD) detection and the consequent protection switching mechanismSlide3
MotivationThe SD condition used for protection switching mostly depends on LM (packet loss ratio) and DM (packet delay and delay variation)
LM need to measure the amount of the lost service packetsSo the detection of SD must be based on service packetsIn 1:1 and 1:n protection architectureThere is no normal traffic on working/protection transport entity, which makes the detection of SD impossible and causes switch flappingSlide4
Motivation
Example for flapping
In fact, there are SD on both working and protection entitiesBut only the SD condition on entity that carries the normal traffic can be detected, which cause the flapping between working and protection entitiesNode ZNode A
Selector Bridge
Selective Selector
W
P
W
P
Selector Bridge
Selective Selector
SD
SD
Normal Traffic
Best Effort TrafficSlide5
SD-Triggered Protection Based on OAMDetection of SD by Test
Test OAM packets can be used to simulate the characteristics of the normal traffic and replace the normal serviceWith the performance monitoring OAM packets (LM) the SD condition of the transport entity can be detectedDetection of SD by CC/CVCC/CV OAM packets can be used instead of normal service in packet loss measurement
LM will count CC/CV packets and the loss measurement is based on CC/CV packets, which will be used as the input of SD condition[Note]: The detection of SD by CC/CV is not recommended when the packet loss is caused by congestion.Slide6
SD-Triggered Protection Based on Broadcast Bridge
Example for Broadcast Bridge with priority of SD-W > SD-P
Protection switching not active: the normal traffic is sent only on the working transport entity Protection switching is active: normal traffic is sent on both working and protection transport entities by closing the switch on Broadcast bridge Node ZNode A
Broadcast Bridge
Selective Selector
W
P
W
P
Broadcast Bridge
Selective Selector
SD
Normal Traffic
Best Effort Traffic
SDSlide7
Next StepFeedback on the listMove to working group draft?Slide8
Questions?Slide9
Additional Slides – Protection ComponentBridge
Selector
Selector Bridge
W
P
Permanent Bridge
W
P
Broadcast Bridge
W
P
Selective Selector
W
PSlide10
Additional Slides - 1+1
Node Z
Node A
Permanent Bridge
Selective Selector
Selective Selector
W
P
W
P
Permanent Bridge
1+1 with Permanent BridgeSlide11
Additional Slides - 1:1
Node Z
Node A
Selector Bridge
Selective Selector
W
P
W
P
Selector Bridge
Selective Selector
Node Z
Node A
Broadcast Bridge
Selective Selector
W
P
W
P
Broadcast Bridge
Selective Selector
1:1 with Selector Bridge
1:1 with Broadcast Bridge