Ethernet Protection using ITU G.8031

Transcription

1 Ethernet Protection using ITU G.8031 Tom McDermott Fujitsu Network Communications, Inc.

2 Why Ethernet Protection? Simple. Implementable on small (pizza-box), extended temperature range equipment - FLASHWAVE CDS Compatible with existing Ethernet switching infrastructure. Does not require MPLS. 1

3 Ethernet OAM Operations, Administration, and Maintenance Ethertype 0x8902: ITU Y.1731 OAM and 802.1ag Connectivity Fault Management Amends 802.1Q. Is largely a proper subset of Y Specifies TLV s for numerous Ethernet OAM functions. Continuity Check, Link Trace, Loopback, Alarm Indication Signal, Remote Defect Indication, Locked, Test signal, Automatic Protection Switching, Maintenance Communication Channel, Frame loss and delay measurements, Some others. 2

4 Ethernet Switch Ethernet Switch VLANs: C-tagged: Pops C-tag and then processes the OAM frame internally. OAM normally in the slow path. Re-inserts (as appropriate) the C-tag on the egress frame. S+C-tagged: Pops S-tag, remaining frame is C- tagged. OAM thus is forwarded (fast path) rather than processed by the bridge maintenance entity. 3

5 Vocabulary ME: Maintenance entity MEG: Maintenance Entity Group 8 MEG levels may be nested. Default assignment: Customer role is assigned three MEG Levels: 7, 6, and 5 Provider role is assigned two MEG Levels: 4 and 3 Operator role is assigned three MEG Levels: 2, 1, and 0 MEP: MEG End Point MIP: MEG Intermediate Point 4

6 Nested Maintenance Entities Service Provider Y User X ETH_TFP ETH_FP ETH FPP Link Network Operator A ETH_FP ETH FPP Link Network Operator B ETH_FP ETH FPP Link User X ETH_TFP ETH_FP UNI NNI UNI UNI_C to UNI_C maintenance entity UNI_N to UNI_N maintenance entity Intra Domain ME Intra Domain ME Access Link ME Inter Domain ME Access Link ME Y.1731 Figure 6-1 Example of MEs associated with a point-to-point connection administrative domain. 5

7 MEPs MEPs may exchange TLV s with peer MEPs e.g.: Continuity Check Frame Delay & Frame Delay Variation Frame Loss Client Signal Fail, Remote Defect Indication. Loopback Test Message Automatic Protection Switching 6

8 CC and Protection Ethernet Continuity Check Fault Management: default transmission period is 1s. Performance Monitoring: default transmission period is 100ms. Protection Switching: default transmission period is 3.33ms. (Typically hardware-assisted). MIP is transparent to CC messages. Protection path is between MEPs Uses CC messages to verify path integrity 3 consecutive missing CC messages lost connectivity. ~ 10 milliseconds protection detect time. Can also trigger switching on Signal Degrade 7

9 Linear Protection (G.8031) Two modes of operation available: 1+1 (permanent head-end bridge) mode 1:1 (non-permanent head-end bridge) mode. Characteristics Available: Unidirectional (1+1 only) or Bidirectional (both modes). Revertive or non-revertive switching (both modes). Extra traffic (low priority pre-emptable traffic utilizing the protection channel when both working and protect channels are functional) is not available in G Vendor proprietary solution 1:1 Selector Bridge Mode allows full capacity of working plus protect channel. G.8031 Multi-chassis protection Effort started in standards. Distributed Selector + inter-chassis protocol. 8

10 Linear Protection Example 9

11 Multi-chassis G

12 Comparison G.8031 with COE G.8032 with Bridging Switching Mechanism Tag/VLAN based MAC bridging /Port Based 50ms protection/restoration Supported Topologies Multicast support Scalability Multiple protection instances per VLAN ID Y Any (linear, mesh, ring) No Carrier: Typically 95% Unicast Increases per VLAN. However proprietary approaches: Representative VLAN fate shared Stitched G.8031 Limit scale issues Y Y Single ring (G.8032v1) or Interconnected rings (G.8032v2) Per link Yes Carrier: Typically 5% Multicast Maximum hop count None 255 MEF Ethernet Service support Traffic Engineering P2P services (EPL, EVPL) Working/Protect paths explicitly defined by EMS. Simple traffic engineering Predictable performance for both paths MP2MP (EP-LAN, EVP-LAN) P2P services (EPL, EVPL) Note: P2P services supported via bridging Working/Protect paths determined by where break in ring occurs (similar to STP) Variable performance between the different paths Y 11

13 1+1 Bidirectional Example Protected ETH#A SNC WEST ETH#A (Normal Traffic) EAST Working Transport Entity (for ETH#A) ETH#A (Normal Traffic) SNC ETH_C Protection Switching Process ETH_FP Protection Transport Entity (for ETH#A) ETH_C SNC Protection Switching Process Protected ETH#A SNC WEST ETH#A (Normal Traffic) EAST Working Transport Entity (for ETH#A) ETH#A (Normal Traffic) SNC Protection Switching Process ETH_C ETH_FP Protection Transport Entity (for ETH#A) ETH_C SNC Protection Switching Process 12

14 Copyright 2010 FUJITSU LIMITED 13