RPR Protection Gal Mor, Corrigent Systems Jim Kao, Cisco Systems

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1 RPR Protection, Corrigent Systems, Cisco Systems

2 Requirements Protection within 50 msec Wrap protection is required Packets may indicate Steering Only Data (SWIS) Steer protection is optional Use Topology Discovery protocol to determine Stations protection method support If all Stations can do both Operator s selection

3 RPR Ring Station 1 Station 6 Station 2 Inner Ring Outer Ring Station 5 Station 3 Station 4 Traffic Flow

4 Unidirectional Fiber Failure Detection {SF,A,W,S} Station A Fiber Cut {SF,A,W,L} Station B {SF,A,W,L}

5 Bidirectional Fiber Failure Detection {SF,A,W,S} Station A Fiber Cut {SF,B,W,S} Station B {SF,A,W,L} {SF,B,W,L}

6 Fiber Failure Detection (cont) Station that detects a failure on its receiver port generates: Broadcast Short message on the opposite ring Broadcast Long message around the ring, away from the failure The Station repeats protection message generation every T1 sec until it receives its protection message back, or until the failure disappears Recommendation: T1=1

7 Unidirectional Fiber Recovery 3. {IDLE,A,I,S} 1. {WTR,A,W,S} Station A Station B 2. {WTR,A,W,L} 4. {IDLE,A,I,L}

8 Bidirectional Fiber Recovery 3. {IDLE,A,I,S} 1. {WTR,A,W,S} Station A 2. {WTR,B,W,S} 4. {IDLE,B,I,S} Station B 2. {WTR,A,W,L} 4. {IDLE,A,I,L} 1. {WTR,B,W,L} 3. {IDLE,B,I,L}

9 Fiber Recovery (cont) Station that detects disappearance of failure on its interface generates: Broadcast Short message with WTR indication on the opposite ring Broadcast Long message with WTR indication around the ring, away from the recovered failure The Station repeats protection message generation every T1 sec until it receives its protection message back, or until WTR expires

10 Fiber Recovery (cont) After WTR period, the Station generates: Broadcast Short message with IDLE indication on the opposite ring Broadcast Long message with IDLE indication around the ring, away from the recovered failure The Station repeats IDLE protection message generation every T1 sec until it receives its message back

11 Wrap Protection {SF,N6,W,L} Station 1 Station 6 Station 2 {SF,N5,W,S} Fiber Cut {SF,N6,W,S} Inner Ring Outer Ring Station 5 {SF,N5,W,L} Station 4 Station 3 Traffic Flow

12 Optional Steering after Wrap Protection Station 1 Station 6 Station 2 Fiber Cut Traffic Flow Inner Ring Outer Ring Station 5 Station 3 Station 4

13 Steer Protection {SF,N6,W,L} Station 1 Station 6 Station 2 {SF,N5,W,S} Fiber Cut {SF,N6,W,S} Inner Ring Outer Ring Station 5 {SF,N5,W,L} Station 4 Station 3 Traffic Flow

14 Steer Protection (cont) Station 1 Station 6 Station 2 Fiber Cut Traffic Flow Inner Ring Outer Ring Station 5 Station 3 Station 4

15 Wrapping Comparison Fastest response to failure, no need to communicate with all other stations for corrective action Lowest packet loss No special multicast/broadcast handling during failure Steering Simpler HW, doesn t require the Mate link Can be revertive or non-revertive

16 SWIS Packets wrap based on type field On failure the wrapping station discards packets with the steering only indication in the type field For steering only packets: Packet source station set type field to: steering only Source station is responsible to perform Steer within 50 msec

17 SWIS Applications Wrap protection for Multicast and Control, Steer protection for Unicast Wrap protection for BE traffic, Steer protection for TDM (low jitter) Wrap protection for packet loss sensitive flows, Steer protection for re-order sensitive flows Enables interoperation between fast-steering Stations and slow-steering Stations (that relies on wrapping within 50msec)

18 Protection Message Messages sent on fault detection/recovery in broadcast style Protection message format: {Request_Type, Source_Address, Wrap_Status, Path_Indicator} Request_Type: Force Switch Signal Fail Signal Degrade Manual Switch Wait to Restore Idle

19 Wrap_Status: Idle Wrap Protection Message (cont) Path_Indicator: Short Message Toward upstream stations on failed ring through the opposite ring Long Message Toward downstream stations on the failed ring

20 Protection Control Message Frame Format TTL Type(4) RI PRI(7) IOP Destination Address Source Address Protocol Type (0x2007) HEC Control Version (0x0) Control TTL IPS Octet FCS Control Type (0x2) Rsvd

21 Conclusions Same message format can be used for both Steering and Wrapping methods Standard should have Wrap as a base case and Steer as an optional case

M U LT I C A S T C O M M U N I C AT I O N S. Tarik Cicic

M U LT I C A S T C O M M U N I C AT I O N S Tarik Cicic 9..08 O V E R V I E W One-to-many communication, why and how Algorithmic approach: Steiner trees Practical algorithms Multicast tree types Basic