1. Satoshi NARIKAWA NTT (G.8032 Acting Co-editor)
Joint ITU-T/IEEE Workshop
on The Future of Ethernet Transport (Geneva, 28 May 2010)
G.8032 : Ethernet Ring protection characteristics, architectures and the Ring APS protocol
Satoshi NARIKAWA
NTT
(G.8032 Acting Co-editor)
Geneva, 28 May 2010

2. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 2

3. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 3

4. Objectives and Principles
Protection switching on Ethernet layer
Use of Ethernet OAM frames called R-APS message for protection behavior
Preventing any loops by blocking mechanism
VLAN based protection switching
Sub-50msec protection switching
Support of administrative commands
Geneva, 28 May 2010 4

5. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 5

6. Basic protection mechanism
R-APS(SF) A B A B A B F C F C F C E D E D E D
R-APS(SF)
Normal condition
Block RPL (Ring Protection Link)
Failure condition
Block failed link
Send R-APS messages
Unblock RPL
Perform FDB flush on all ring node as needed
Geneva, 28 May 2010 6

7. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 7

8. G.8032 (06/2008) Revision approved in June 2008 Supported Features
Single ring protection
Revertive behavior
State based flush logic
Ring
Geneva, 28 May 2010 8

9. G.8032 (04/2009) Amendment approved in April 2009 Supported Features
Multi-ring protection with R-APS Virtual Channel
Revertive behavior
State based flush logic
Flush propagation
Major
Major
Major
Sub
Sub
Sub
Geneva, 28 May 2010 9

10. G.8032 (03/2010) Revision approved in March 2010 Supported Features
Multi-ring protection with/without R-APS Virtual Channel
Revertive/non-revertive behavior
Flush logic with Node-ID and BPR (Blocked Port Reference) mechanism
Administrative commands (Manual/Forced switch, Clear)
Ability to block RPL at both ends of link
Multiple (logical) ERP Instances over a given physical ring
Major
Major
Major
Major
Sub
Sub
Sub
Sub
Sub
Geneva, 28 May 2010 10

11. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 11

12. Interconnected Rings
G.8032 supports for a network of interconnected rings based on the following terminology.
Interconnection Node
connects between Ethernet rings
Major Ring
constitutes a closed ring
is controlled by its own ERP instance with its own RPL
Sub-Ring
is connected to a Major Ring or upper Sub-Ring via the Interconnection Nodes and does not constitute a closed ring
Major
Major
Sub
Sub
Major
Major
Sub
Sub
Major
Sub
Sub
Geneva, 28 May 2010 12

13. R-APS Virtual Channel
The 2010 version supports two implementation options for R-APS control channel of the Sub-Ring.
with R-APS Virtual Channel
without R-APS Virtual Channel
In the first option, R-APS messages are encapsulated and transmitted over an R-APS Virtual Channel configured on the Major Ring.
In the second option, R-APS messages are terminated at the Interconnection Nodes but not blocked at RPL of the Sub-Ring.
R-APS Virtual Channel
Major
Major
Major
Major
R-APS
Channel
Sub
Sub
Sub
Sub
Physical Ring
R-APS Channel
of Major Ring
R-APS Channel
of Sub-Ring
with R-APS
Virtual Channel
R-APS Channel
of Sub-Ring
without R-APS
Virtual Channel
Geneva, 28 May 2010 13

14. Administrative commands
New revision supports basic operator administrative commands
Forced Switch (FS)
– allows operator to block a particular ring port
Effective even if there is existing SF condition
Multiple FS commands supported per ring
May be used to allow immediate maintenance operations
Manual Switch (MS)
Not effective if existing FS or SF condition
Overridden by new FS and SF conditions
New MS commands are ignored
Clear
– cancels an existing FS/MS command on the ring port
May be used (at RPL Owner Node) to trigger reversion
Geneva, 28 May 2010 14

15. Multiple ERP instances
New revision supports multiple ERP instances
ERP instance is composed of a set of VLANs.
Multiple ERP instances can be configured on a same physical ring.
ERP instance protects a subset of the VLANs that transport traffic over the physical ring.
Each ERP instance is independent of other ring instances.
Instance 1
Instance 2
Geneva, 28 May 2010 15

16. R-APS message R-APS message format (based on Y.1731 APS)
Geneva, 28 May 2010 16

17. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 17

18. Dual node interconnection
Future work item 1
End-to-end service resiliency
Resilient metro/core network can be realized by G.8032v2, but access network is not yet supported by ring protection. Guidelines for providing end-to-end resilient service are under study.
Access network
G.8032
Dual node interconnection
Access network
Geneva, 28 May 2010 18

19. Future work item 2 Multiple failure recovery
In some cases, ring segmentation occurs due to multiple failures. Guidelines for a mechanism to minimize its effect are under study.
The 2010 version
under study
Major
Major
Major
Major
Sub
Sub
Sub
Sub
Normal condition
Single failure condition
Double failure condition
Moving blocked link
Geneva, 28 May 2010 19

20. Other future work items
Reduced consumption of VIDs
Method to reduce the number of VIDs allocated for R-APS control channel
FDB Flush optimization
Method to minimize the effect of flooding in case of protection switching or reversion
Geneva, 28 May 2010 20

21. Objectives and Principles Basic protection mechanism Revision notes
Outline
Objectives and Principles
Basic protection mechanism
Revision notes
Detailed functionality
Future work
Summary
Geneva, 28 May 2010 21

22. Summary
G.8032 provides resilient Ethernet network by using ring architecture.
The 2010 version supports multi-ring protection switching with functionality such as:
Revertive/non-revertive mode
Administrative commands
Multiple ERP instances
etc…
Some additional topics are under study including:
End-to-end service resiliency
Multiple failure recovery
Geneva, 28 May 2010 22

23. Thank you