Segment Protection Models M Vinod Kumar Dr. Abhay Karandikar

Agenda Definitions and Abbreviations Prior art Possible models Comparison of models

Definitions and Abbreviations Segment: A logical management entity defined over transitive closure of bridges and LANs or linear/open chain of connected bridges Segment Edge Bridge (SEB): The bridge that defines end point of a segment Infrastructure Segment (IS): Data-path Segment (DS): BB-BEB: 3-tupple translation bridge that translates incoming TESI to outgoing TESI. At finer granularity is may also do I-SID grooming.

Prior Arts Eilat (May Interim) Denver (July Plenary) Tejas presents SPS as means to solve P2MP protection ay-Abhay-Protection-Switching-for-P2MP-0508.ppt Denver (July Plenary) Jointly with Huawei and Adtran new-sultan-fast-reroute-te-0708-v02.pdf Seoul (Sept Interim) Huawei presents interpretations new-sultan-segment-protection-scaling-0908-v01.pps Nortel presents issues to address new-martin-PBB-TE-segment-prot-0908-v01.pdf Tejas presents case for SPS new-Protection-Vinod-Case-for-Segment-Protection-0908-v1.pps Dallas (Nov Plenary) Tejas uploads document on case for SPS new-Vinod-SegmentProtectionSwitching-1108-v01.doc No new work prez due to Lack of time new-martin-PBB-TE-segment-prot-1108-v00.pdf new-sultan-segment-protection-requirements-1108-v02.pdf New Orleans (Jan Interim) Tejas, Nortel, Huawei, ZTE, Adtran, …

Segment Protection Models Server Layer Model Triple MAC or Mac-in-Mac-in-Mac Triple Q or B-VID-in-B-VID or New VID-Ethertype Segmented Domain Model Segmented Q-in-Q Segmented PBB-TE (B-B BEB)

Server Layer Models Triple MAC Triple Q

Triple MAC

Triple MAC (SEB in middle) Work-IS 1 2 3 4 5 SEB I-tagged frame Protect-IS IB-BEB NMS trace route will be issue: inner domain is invisible to outer domain- whether it is 1-2-3-4 or 1-2-5-3-4? B-tagged frame BCB

Model Components When SEB is not at the BEB S-tagged frame I-comp I-tagged MiM frame B-comp B-tagged MiM frame

Triple MAC (SEB at Edge) IB-IB-BI-BI BI-IB Primary-IS 1 2 3 4 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component When SEB is at the BEB S-tagged frame I-comp B-comp B-tagged frame

Operations and Integrity SEB => I-comp + B-comp (Can we avoid I-comp? No) If SEB is defined at node 4 instead of node 2 or 3 then MAC-in-MAC-in-MAC function is needed at node 4 New and complex Chip Integrity breaks or is not applicable as original M-i-M frame acts as client layer to the Segment Server layer 1:1 PG integrity is not same as e2e service integrity NMS trace route function has to maintain two valid routes 1-2-3-4 and 1-2-5-3-4 Throughput decreases Provisioning over segment cannot be done independently of e2e provisioning This is contrary to Client and Server layer principle which assumes that provisioning in client and server are independent

Final Model Component When SEB is not at the BEB S-tagged frame I-comp I-tagged MiM frame B-comp B-tagged MiM frame When SEB is at the BEB S-tagged frame I-comp B-comp I-comp B-comp B-tagged frame

Forwarding Ambiguity Problem Forwarding Ambiguity arises in the two segments given below because forwarding in Datapath segments is based on end-to-end DA+B-VID node 5 cannot know if fault is in link 2-3 or 3-4 Primary-IS Primary-IS Single Fault 1 ? 2 3 4 No Fault Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

No Forwarding Ambiguity BI-IB IB-IB-BI-BI Primary-IS Primary-IS 1 2 3 4 Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB There is no forwarding ambiguity as the 3-tuple is different for every segment B-tagged frame BCB

Triple Q

Triple Q (SEB in Middle) Primary-IS 1 2 3 4 Additional VLAN tag for each segment 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component When SEB is not at the BEB B-tagged QiQ frame S-comp S-tagged QiQiQ frame New Ethertype?

Triple Q (SEB at Edge) S-S S-BI Primary-IS Primary-IS 1 2 3 4 Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component When SEB is at the BEB S-tagged frame IB-comp B-tagged QiQ frame S-comp S-tagged QiQiQ frame New Ethertype?

Operations and Integrity SEB => S-comp + S-comp If segment is defined at node 4 instead of node 2 or 3 then Q-in-Q-in-Q function is needed New and complex Chip Integrity breaks or is not applicable as original M-i-M frame acts as client layer to the Segment Server layer 1:1 PG integrity is not same as e2e service integrity Throughput decreases NMS trace-route issue just as in Triple-MAC

Final Model Component When SEB is not at the BEB B-tagged QiQ frame S-comp S-tagged QiQiQ frame New Ethertype? When SEB is at the BEB S-tagged frame IB-comp B-tagged QiQ frame S-comp S-tagged QiQiQ frame New Ethertype?

No Forwarding Ambiguity S-S S-BI Primary-IS Primary-IS 1 2 3 4 Backup-IS VIDs are different for every cascaded segments protecting the same service 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Segmented Domain Models Segmented Q Segmented PBB-TE or BB-BEB

Segmented Q (SEB in Middle) Even though Segment is not defined between 3-4 new VLAN is needed Primary-IS 1 2 3 4 New VLAN tag for each segment 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component Internal point When SEB is not at the BEB B-tagged MiM frame B-comp I-tagged MiM frame B-comp B-tagged MiM frame

Segmented Q (SEB at BEB) B-I B-B Primary-IS Primary-IS 1 2 3 4 New VLAN tag for each segment Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component When SEB is at the BEB S-tagged frame I-comp B-comp B-tagged MiM frame

Operations and Integrity Maintaining same end-to-end ESP-VID is impossible sometimes B-VLAN translation => B-comp + B-comp I-SID shall not be multiplexed or looked into B-MAC remains same end-to-end; only VID changes Blue VID terminates at 2 on to a protection group: PG(cyan, Red) PG(cyan, Red) terminates on Brown VID (or on Blue to maintain ESP-VID requirements) Integrity breaks or is not applicable as VID in original M-i-M frame changes within the Segment Domain 1:1 PG integrity is not same as e2e service integrity Throughput does not decrease as frame size is same

Final Model Component Internal point When SEB is not at the BEB B-tagged MiM frame B-comp I-tagged MiM frame B-comp B-tagged MiM frame When SEB is at the BEB S-tagged frame I-comp B-comp B-tagged MiM frame

No Forwarding Ambiguity B-B Primary-IS Primary-IS 1 2 3 4 Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB B-MAC remains unchanged so to prevent forwarding ambiguity VID should be different B-tagged frame BCB

Segmented PBB-TE or B-B BEB

Segmented PBB-TE or BB-BEB (SEB in Middle) Irrespective of Segment defined between 3-4 new VLAN is needed Primary-IS 1 2 3 4 New 3-tupple for each segment 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component Internal point When SEB is at the BEB B-tagged MiM frame B-comp I-tagged MiM frame B-comp B-tagged MiM frame

Segmented PBB-TE or BB-BEB (SEB at BEB) B-I B-B Primary-IS Primary-IS 1 2 3 4 New 3-tupple for each segment Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB B-tagged frame BCB

Model Component When SEB is at the BEB S-tagged frame I-comp B-comp B-tagged MiM frame

Operations and Integrity SEB => B-comp + B-comp TESI translation, incoming TESI is mapped to outgoing TESI At finer granularity I-SID mux-demux can also be done Smaller PBB-TE segments interacting as peers Integrity is not applicable as original M-i-M frame terminates and new M-i-M frame starts PG function is same as defined in e2e service N:1 PG to be defined Throughput remains same

Final Model Component Internal point When SEB is not at the BEB B-tagged MiM frame B-comp I-tagged MiM frame B-comp B-tagged MiM frame When SEB is at the BEB S-tagged frame I-comp B-comp B-tagged MiM frame

No Forwarding Ambiguity B-B Primary-IS Primary-IS 1 2 3 4 Backup-IS 5 SEB I-tagged frame Backup-IS IB-BEB 3-tupple differs from segment to segment so there will never arise forwarding ambiguity B-tagged frame BCB

Pros and Cons Features Triple MAC Triple Q Segmented Q Segmented PBB-TE or BB-BEB Best of all ? Throughput Lowest Low Same same Feasibility New Chip S-Comp B-B comp Forwarding Ambiguity No Integrity issue Not applicable Not Applicable Standards compliant May be PBB PBB, PBB-TE Applications Only SPS Yes (SPS, PBB+VPLS, I-SID aggregation, ENNI-2) Protection Group 1:1 1:1 (Could be different VID) 1:1 (and N:M) Processing in middle Highest High High or highest Processing at edge Same or high

Questions?