Co-ordination Between Segment Protection and Global Protection M Vinod Kumar Abhay Karandikar Version 1.0

Infrastructure Segment Protection Case 1 ISP Not Required; Only Global Protection (GP) Needed ISP Required Case 2 Case 3 ISP without GP ISP with GP Case 3a Case 3b First ISP and then GP Certain TESI is outside the scope of ISP; Only GP for them Case 3a FT Case 3a C or FBT Alan McGuire’s (BT) Requirement Fixed Timer Coordination or Feedback Based Timer GP Timer > ISP Timer Efficient and Reliable Need a mechanism to identify it e.g. MST-ID 5/7/2019 Tejas Networks Ltd

Case 1 Infrastructure Segment Protection not required; only Global Protection Work TESI BEB1 SEB1 SEB2 BEB2 Protect TESI N1 Bridge Link N2 5/7/2019 Tejas Networks Ltd

Case 2 Only Infrastructure Segment Protection required but NO Global Protection Work ISP CCM Work TESI CCM BEB1 SEB1 SEB2 BEB2 N1 Protect ISP CCM Bridge Link N2 5/7/2019 Tejas Networks Ltd

Case 3 Infrastructure Segment Protection with Global Protection Work ISP CCM Work TESI CCM BEB1 SEB1 SEB2 BEB2 Protect TESI CCM N1 Protect ISP CCM Bridge Pre-Provisioning of Work TESI/ CCM Link N2 5/7/2019 Tejas Networks Ltd

Observation Among the 3-cases depicted only case-3 needs extra care We consider first Case 3b and then Case 3a 5/7/2019 Tejas Networks Ltd

Case 3b TESI is outside the scope of Infrastructure Segment Protection Could use different MST-ID Work ISP CCM Work TESI CCM BEB1 SEB1 SEB2 BEB2 Protect TESI CCM N1 Protect ISP CCM Bridge Pre-Provisioning of Work TESI/ CCM Link N2 5/7/2019 Tejas Networks Ltd

Case 3a Fixed Timer Infrastructure Segment Protection with Global Protection If link SEB1-SEB2 fails, Segment Protection should be done before Global Protection So HoldOffTimer T2>T1, How do we set this? How large should be T2? This will slow the Global Protection. Not reliable. So Case 3a Coordination or Feedback Based Timer is ideal Work ISP CCM T2 > T1 T1 Work TESI CCM BEB1 SEB1 SEB2 BEB2 Protect TESI CCM N1 Protect ISP CCM Bridge Pre-Provisioning of Work TESI/ CCM Link N2 5/7/2019 Tejas Networks Ltd

Case 3a Coordination or Feedback Infrastructure Segment Protection with Global Protection If link SEB1-SEB2 fails, then SEB1 and SEB2 will coordinate with BEB1 and BEB2 informing that ISP will handle the fault Feedback Feedback Work ISP CCM Work TESI CCM BEB1 SEB1 SEB2 BEB2 Protect TESI CCM N1 Protect ISP CCM Bridge Pre-Provisioning of Work TESI/ CCM Link N2 5/7/2019 Tejas Networks Ltd

Conclusion Coordination is a mandatory requirement in Case 3a Will increase reliability and speed. 5/7/2019 Tejas Networks Ltd

Thanks 5/7/2019 Tejas Networks Ltd