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

2. 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

3. 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

4. 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

5. 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

6. 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

7. 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

8. 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

9. 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

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

11. Thanks
5/7/2019
Tejas Networks Ltd