G.8032 : Ethernet Ring protectioncharacteristics, architectures
and the Ring APS protocol
Satoshi NARIKAWANTT
(G.8032 Acting Co-editor)
Joint ITU-T/IEEE Workshop on The Future of Ethernet Transport
(Geneva, 28 May 2010)
Geneva, 28 May 2010
Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 2
Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 3
Objectives and Principles
Protection switching on Ethernet layerUse of Ethernet OAM frames called R-APS message for protection behavior Preventing any loops by blocking mechanismVLAN based protection switchingSub-50msec protection switchingSupport of administrative commands
A B
E D
F C
A B
E D
F C
A B
E D
F C
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Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 5
Basicprotection mechanism
Normal conditionBlock RPL (Ring Protection Link)
Failure conditionBlock failed linkSend R-APS messagesUnblock RPLPerform FDB flush on all ring node as needed
A B
E D
F C
A B
E D
F C
A B
E D
F C
R-APS(SF)
R-APS(SF)
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Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 7
G.8032 (06/2008)
Revision approved in June 2008Supported Features
Single ring protectionRevertive behaviorState based flush logic
Ring
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G.8032 (04/2009)
Amendment approved in April 2009Supported Features
Multi-ring protection with R-APS Virtual ChannelRevertive behaviorState based flush logicFlush propagation
Major Major
Sub SubSub
Major
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G.8032 (03/2010)
Revision approved in March 2010 Supported Features
Multi-ring protection with/without R-APS Virtual ChannelRevertive/non-revertive behaviorFlush logic with Node-ID and BPR (Blocked Port Reference) mechanismAdministrative commands (Manual/Forced switch, Clear)Ability to block RPL at both ends of linkMultiple (logical) ERP Instances over a given physical ring
Major Major
Sub SubSub
Major Major
Sub
Sub
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Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 11
Interconnected Rings
G.8032 supports for a network of interconnected rings based on the following terminology.
Interconnection Nodeconnects between Ethernet rings
Major Ringconstitutes a closed ringis controlled by its own ERP instance with its own RPL
Sub-Ringis connected to a Major Ring or upper Sub-Ring via the Interconnection Nodes and does not constitute a closed ringis controlled by its own ERP instance with its own RPL
Major
Major
Major
Major
Sub Sub
Sub
Major
Sub
Sub
Sub
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R-APS Virtual Channel
The 2010 version supports two implementation options for R-APS control channel of the Sub-Ring.
with R-APS Virtual Channelwithout 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.
Major
Sub Sub
Major
R-APS Channelof Major Ring
R-APS Channelof Sub-Ringwith R-APS
Virtual Channel
Sub
Major
R-APS Channelof Sub-Ring
without R-APSVirtual Channel
Major
Sub
Physical Ring
R-APS Virtual Channel
R-APSChannel
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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 conditionMultiple FS commands supported per ringMay be used to allow immediate maintenance operations
Manual Switch (MS) – allows operator to block a particular ring port
Not effective if existing FS or SF conditionOverridden by new FS and SF conditionsNew 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
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Multiple ERP instances
New revision supports multiple ERP instancesERP 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
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R-APS message
R-APS message format (based on Y.1731 APS)
Status ReservedBPR
DNF
RB
Node ID (6 octets)StatusSub-code
Node ID9
Reserved 2 (24 octets)13
……
End TLV (0)last
[optional TLV starts here; otherwise End TLV]37
Request/State
5
TLV Offset (32)Flags (0)OpCode (R-APS = 40)Version (1)MEL1
12345678123456781234567812345678
4321
Status ReservedBPR
DNF
RB
Node ID (6 octets)StatusSub-code
Node ID9
Reserved 2 (24 octets)13
……
End TLV (0)last
[optional TLV starts here; otherwise End TLV]37
Request/State
5
TLV Offset (32)Flags (0)OpCode (R-APS = 40)Version (1)MEL1
12345678123456781234567812345678
4321
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Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 17
Future work item 1
End-to-end service resiliencyResilient 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.
G.8032
Dual node interconnection
Access network
Access network
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Future work item 2
Multiple failure recoveryIn some cases, ring segmentation occurs due to multiple failures. Guidelines for a mechanism to minimize its effect are under study.
Major
Sub
Major
Sub
Major
Sub
Major
Sub
The 2010 version
under study
Normal condition Single failure condition Double failure condition Moving blocked link
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Other future work items
Reduced consumption of VIDsMethod to reduce the number of VIDs allocated for R-APS control channel
FDB Flush optimizationMethod to minimize the effect of flooding in case of protection switching or reversion
Geneva, 28 May 2010 20
Outline
Objectives and PrinciplesBasic protection mechanismRevision notesDetailed functionalityFuture workSummary
Geneva, 28 May 2010 21
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 modeAdministrative commandsMultiple ERP instancesetc…
Some additional topics are under study including:End-to-end service resiliencyMultiple failure recoveryetc…
Geneva, 28 May 2010 22
Thank you