Service Resiliency ITU-T SG15 Q9 Activities Ghani Abbas Ericsson 25th.,June, 2012 Geneva Workshop - Disaster Relief Systems and Network Resilience and Recovery Topics › Q9/15 Task › Network Objectives and Requirements › Approved Recommendations › Protection Architectures › Recommendations under development › Network Restoration › Protection schemes – interworking and guidelines › Summary Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 2 Q9/15 – Network Protection and Restoration Work - One of the task is addressing enhanceMENT to Transport equipment functionality Recommendations to provide Survivability capabilities as well as addressing multi-layer survivability interactions. - The work covers all transport technologies SDH, ATM, OTN, Ethernet and MPLS-TP including interaction with protection at data/packet layers Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 3 Protection: Network Objectives and Requirements › Protection against one (or more) defects/failures › Protection switching to be completed in less than 50ms › Protection switching is invoked by LOS and OAM defects › Various architecture schemes – linear, 1+1, 1:1, 1:n, uni and bi-directional, ring and mesh › Revertive and non-revertive › Automatic Protection Switching (APS) protocol › APS messages are prioritized › APS is exercised to ensure satisfactory operation › External operator commands are supported Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 4 Protection Switching - APPROVED Recommendations -Linear protection - Generic : G.808.1 - OTN : G.873.1 - Ethernet : G.8031 - MPLS-Tp: G.8131? - Ring Protection - Generic : G.808.2 - OTN : G.873.2 - Ethernet : G.8032 - MPLS-T : G.8132? Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 5 1:1 and 1+1 Protection Architectures - Fast (sub 50ms) switching - Protects against fibre cuts and often interface cards failures Equipment A Worker Fibres Equipment B 1:1 Protection Fibres Equipment A Worker Fibres Equipment B 1+1 Protection Fibres Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 6 Ring Protection - Fast (sub 50ms) switching - Optimised protection for ring architectures Protection fibres Worker fibres Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 7 X Failure occurs Current Work › Shared Mesh protection – Generic : G.smp – Packet? - OTN: G.otnsmp › Inter-working of currently ITU SG15 standardised Schemes › Guidelines/Use cases of protection schemes › Network scenarios and used cases for Ethernet Ring protection schemes Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 8 Protection Interworking - InterworkinG of currently ITU SG15 standardised Schemes - eg. G.8032/ G.8031, G.873.1/G.8032 interworking etc -Guidelines/Use cases of protection schemes - Network scenarios and used cases for EtherNET protection schemes - focus on MBH applications and G.8032 and G.8031 scenarios Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 9 Protection Interworking ..1/2 G.8032/G.8031 Interworking Example G.8032 G.8032 Distributed G.8031 Domain 1 Domain 2 Domain 3 G.8032 G.8032 Distributed G.8031 Domain 1 Domain 2 Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 10 Domain 3 Protection Interworking …2/2 G.8032 /G.873.1 Interworking Example G.8032 G.8032 Distributed G.873.1 Domain 2 Domain 1 G.8032 Domain 3 G.8032 Distributed G.873.1 Domain 1 Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 11 Domain 2 Domain 3 Shared Mesh Protection (SMP) Current status › Q9/15 is developing a generic Recommendation for SMP › The main objective for SMP is to reduce operating cost by sharing protection resources instead of dedicated protection resources › SMP operates independent of control plane › A technology specific ODU SMP protection scheme based on generic SMP is also being considered. Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 12 SMP Concept Node A Node B Node A Node B Working 1 PS1 Working 1 PS2 Node C Node D Node C PS1 PS3 Node E PS4 Node D PS3 PS5 Node F Node E PS4 Working 2 Cross-connect controller PS2 PS5 Node F Working 2 Protection segment Bridge and selector functions Protection segment › 1 protection segment is shared by multiple protection paths › The protection connection should be configured to reserve protection resource in advance › Switching activation is based on data plane Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 13 Important Aspects of SMP Over-subscription:: “Each timeslot may be used by multiple connections” Preemption:: “If the working channel suffers failure and its setup priority is higher than current one on the protection channel, the channel on the protection gets chucked out!” Working Connection X B C A D Protecting Connection X’ E F G Protecting Connection Y’ H K 1:N Protection: with multiple protection requests, the channel with highest preference level will take over.” I J Working Connection Y L M Protecting Connection Y’’ Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 14 N Protection and Restoration › Most existing networks use pre-planned protection – Network resource centrally controlled – Protection pre-allocated and predicable › Restoration – Initially sets up worker only – Protection occurs dynamically on failure – Effectively statistical and non-deterministic – Protection Bandwidth is shared between many workers – Generally Control Plane is involved in the restoration scheme Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 15 Network Restoration › Traditional protection is fixed – Pre-calculated by a central manager – Operation fixed and predictable – Network equipment has no network topology awareness › Restoration protection is dynamic – Only worker traffic is set up – Shared protection - protection calculated dynamically on failure › Restoration is fundamentally different approach requiring – – – – – Network topology discovery Routing algorithms Peer to peer signalling Traffic engineering More cost effective – Protection Bandwidth is shared by many workers Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 16 Restoration Protection 1.3.Circuit set upnode A to B Originating 4. Originating node calculates a new path signals new path set up 2. Failure occurs X A Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 17 B Restoration Protection 5 Circuit restored. X A Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 18 B Ethernet Ring Protection Supplement – Current Status The supplement will provide network scenarios, Usage guidelines and examples for G.8032 applicability. It will describe the following: › ERP in support of network applications (e.g., Mobile Backhaul, Business Services, etc.) › ERP in support of Ethernet services › Interconnected ERP ring examples › Guidelines for configuration and management procedures for ERP › End-to-end network/service resiliency involving ERP Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 19 End-to-end service resilience in Ethernet ring protection G.8032 - An example for Access links Access links G end-to-end service resilience C E A UNI B ERP D UNI F H End to end resilience is needed K C End-to-end service resilience over interconnected rings A L Sub-Ring D J Major Ring M Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 20 Sub-Ring H G E F B Summary › A number of approved recommendations define fast protection schemes covering all transport technologies › Shared Mesh Protection work is progressing well › Network restoration using control plane for various transport technologies is also standardized Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 21 Commercial in confidence | © Ericsson AB 2010 | 2012-06-25 | Page 22