Carrier Ethernet Technology and Standards Update Presented by

Carrier Ethernet Technology and Standards Update Presented by: Rick Gregory Senior Systems Consulting Engineer May 25, 2011 © Ciena Confidential and Proprietary 1

Carrier Ethernet: Evolution, Defined © Ciena Confidential and Proprietary 2

Ethernet Evolution Timeline 1970 s to today 1973 Metcalfe & Boggs of Xerox PARC invented ALOHA packet-based network access protocol over a wired shared medium à 1982 3 Mb/s operation “The Ethernet Blue Book” Digital, Intel, Xerox (DIX) à 1985 10 Mb/s operation based on the Xerox PARC concepts IEEE 802. 3 Carrier Sense Multiple Access w/ Collision Detection (CSMA/CD) à 1999 Formal standards definition, based on “Blue Book” Gigabit Ethernet standards ratified for use over copper twisted pair; vendors also implement fiber optic versions; 1000 Base-T à 2000’s IEEE 802. 3 ab Fiber standards ratified for single and multimode fiber; speeds evolve to 10, 40 and (eventually) 100 Gbps © Ciena Confidential and Proprietary 3

Ethernet Evolution Events Effect: Carrier Ethernet becomes Leading Transport Technology Events Effects International standardization Ethernet is the first global network access technology Access, metro, and wide-area Unrivaled success in enterprise applications Large number of component and Lowest cost per megabit; < 8¢ per equipment manufacturers megabit for triple-speed NIC Mature, transparent layer 2 technology Simple plug-and-play installation Ethernet over any media…any service over Ethernet © Ciena Confidential and Proprietary 4

Basic Ethernet Bridging (IEEE 802. 1 D) Unknown Destination Multicast Broadcast Forwarding Table Address Port A B C D E F 1 2 2 3 3 3 A switch builds forwarding table by LEARNING where each station is (relative to itself) by watching the SA of packets it receives. Four Important Concepts/Operations (upon switch receipt of a packet): 1. LEARNING: The Source MAC Address (SA) and port number, if not known 2. FORWARDING: Looking up Destination Address (DA) in table and sending to correct port 3. FILTERING: Discarding packets if destination port = receiving port 4. FLOODING: Sending to all other ports if DA is unknown, multicast or broadcast © Ciena Confidential and Proprietary 5

Ethernet’s Evolution Originally 10 Mbps, then 100 M Now 1 Gbps, 10 G, 40 G, 100 G Half Duplex Full Duplex Yes (CSMA/CD) No Collisions (Full Duplex) Entire LAN VLAN Controlled None 802. 1 p Topology Bus E-LAN, E-Tree, E-Line (Access, Trunks) Cabling Coax UTP, Optical (Access, Trunks) Less Than 30% Due to Collisions Approaching 100% Bandwidth Transmission Collisions Broadcast Domain Prioritization Utilization Distance © Ciena Confidential and Proprietary Limited by CSMA/CD Propagation Time Limited Only by Media Characteristics 6

Standards: Current, Forthcoming, and Direction © Ciena Confidential and Proprietary 7

Scaling Ethernet…beyond 802. 1 ad (Q-in-Q) à Preferred: “Large” number of customers à Reality: One MAC domain for customer and Provider results in large forwarding table size à 48 -bit MAC address (no ‘prefixing’ as in IP address) à Every network switch needs to learn Destination Address (DA) of customer switches à Preferred: Customer Isolation/Transparency à Reality: One L 2 broadcast domain for customer and provider à Broadcast storms in one customer’s network can affect other customers and provider as well à Preferred: Million+ service instances à Reality: Limited VLAN space, i. e. , only 4095 (i. e. , 212 -1) à 802. 1 ad (Q-in-Q) suggested 16 million+ instances but forwarding only to same S-tag (4095!) à Preferred: Deterministic behavior for services à Reality: “p” bit for priority but no bandwidth guarantee & arbitrary forwarding/backup paths à Data plane dependent on address table, vlan partition, spanning tree, bandwidth contention © Ciena Confidential and Proprietary 8

Ethernet Transport at Layer 2 & 2. 5: Approaches to COE à VLAN and Stacked VLAN (Q-in-Q) Cross-Connects à Explicit forwarding paths using VLAN based classification. Tunneling via VLAN tag encapsulations and translations. Defined in IEEE 802. 1 Q and IEEE 802. 1 ad specifications. Standards completed. à Provider Backbone Bridging (PBB-TE) and Provider Backbone Bridging (PBB) à Explicitly forwarding paths using MAC + VLAN tag. Tunneling via MAC-in-MAC encapsulations. Defined in IEEE 802. 1 Qay and IEEE 802. 1 ah specifications. Standards completed. à E-SPRing à Shared Ethernet Ring Topology based Protocol mechanism that delivers sub-50 ms in IEEE 802. 1 Q and IEEE 802. 1 ad (Q-in. Q) Ethernet Networks. Defined in ITU G. 8032 specification. Standards completed. à MPLS & VPLS/H-VPLS à Widely deployed in the core, less so in the metro / access. Uses pseudo wire emulation edge-toedge (PWE 3) for Ethernet and multi-service tunneling over IP/MPLS. Can be point-to-point or multipoint (VPLS). Defined in IETF RFC 4364 (formerly 2547 bis) and Dry Martini (IETF RFC 2026). Standards completed. à Provider Link State Bridging (PLSB) à Adds a SPB (Shortest Path Bridging) using IS-IS for loop suppression to make Ethernet fit for a distributed mesh and point to multi-point routing system. PBB-TE/PBB along with PLSB can operate side-by-side in the same network infrastructure. PLSB is optimized for Any to Any E-LAN and Point to Multi-Point E-Tree Network Topology Service delivery. Defined in IEEE 802. 1 aq specification. Standards to be completed. Target completion approximately 2 H 2011. à MPLS-TP à Formerly know as T-MPLS (defined by ITU-T). New working group formed in IETF now called MPLS-TP. Transport-centric version of MPLS for carrying Ethernet services based on PWE 3 and © Ciena Confidential Proprietary LSPandconstructs. Defined in IETF RFC 5654. Standard to be completed. 9 Target completion approximately 1 H 2012.

What’s Next in Carrier Ethernet ? 802. 1 aq PLSB G. 8032 802. 1 Qay PBB-TE Y. 1731 Performance Management 802. 1 ag Fault Management 802. 1 ah PBB Robust L 2 Control Plane Ethernet Shared Ring Resiliency Traffic Engineered Ethernet Tunnels Proactive Performance Management Service and Infrastructure CFM Diagnostics Scalable, Secure Dataplane Ethernet has steadily evolved to address more robust networking infrastructures © Ciena Confidential and Proprietary 10

CESD Technology and Mechanisms OAM And QOS Ethernet Service Monitoring March 2010 © Ciena Confidential and Proprietary 11

Design Predictable Resilience Create a stable network, that remains stable as it scales à Ciena is the leader in Connection-oriented Ethernet (COE) and provides a range of carrier-class resiliency schemes (RSTP, MPLS, PBB-TE) à COE tunnels (PBB-TE, MPLS-TP (future)) are connection-oriented and traffic engineered à Provides deterministic performance for predicable SLAs à Better resiliency & stability of provider networks 802. 1 Q/ad domains protected using 802. 1 w RSTP with 50 ms restoration © Ciena Confidential and Proprietary PBB-TE domain supporting sub-50 ms protection (via 802. 1 ag Connectivity Check Messages) 12

Design Granular Bandwidth Controlled & measurable for predictable Qo. S CIR/EIR à Specific service identification with rich L 1 -L 2 classification 20/0 Voice VLAN 10/100 MAC DA B 20/100 L 2 VPN 50/100 80/200 à Segmented bandwidth via a hierarchy of “virtual ports” à Flexible priority resolution for Co. S mapping à Traffic profiles and traffic management at DENY IP SA 192. 168. 1. 23 10/40 MAC SA A 20/55 TCP port 80 Flow Interface Sub-Port (e. g. Combo of Logical Port TCP/UDP port, IP (e. g. Dept DSCP, MAC, etc. ) VLAN range) (e. g. all the client ports of a Business) all levels in the hierarchy à Specify CIR/CBS, EIR/EBS, Color Aware profiles Enhance revenue with Service Stratification à Allows efficient service upgrades © Ciena Confidential and Proprietary 30/100 13

Operate Comprehensive OAM Reduce the cost to run the network and keep services profitable Complete standards-based Operations, Administration, and Maintenance (OAM) offering provides visibility, manageability, and controls à Proactive SLA assurance, rapid fault isolation and minimized downtime à Includes L 2 and L 3 based performance measurement capability as a way to differentiate services Layer 3 SLA Monitoring & Metrics: Delay, Jitter IETF RFC 5357 TWAMP Two-Way Active Measurement Protocol Layer 2 SLA Monitoring & Metrics: Delay, Jitter, Frame Loss ITU-T Y. 1731 Ethernet OAM IEEE 802. 1 ag CFM Service Heartbeats, End-to-End & Hop-by-Hop fault detection Connectivity Fault Management Enhanced troubleshooting, rapid network discovery © Ciena Confidential and Proprietary IEEE 802. 3 ah EFM Physical Link 14

Technology Options for Packet Transport Packet transport Subscriber Management IP/MPLS Service Edge & Core Metro access & aggregation à Routing, i. e. , forward IP packets à IP -over- {IPsec, GRE -over-} MPLS à IP -over- {IPsec, GRE -over-} IP à MPLS -over- L 2 TPv 3 -over- IP à Ethernet -over- L 2 TPv 3 -over- IP “Application” “Service” Management Bridging, i. e. , forward Ethernet frames based on MAC DA à Ethernet -over- Ethernet: PBB à Ethernet -over- MPLS: VPWS & VPLS Switching, i. e. , forward of Ethernet frames based on tunnel label à Ethernet -over- Ethernet: PBB-TE à Ethernet -over- MPLS-TP MPLS (L 3) IP PBB MPLS (L 2) PBB-TE MPLS-TP Goal: cost-effective, high-performance transport © Ciena Confidential and Proprietary 15

Mechanisms to Build the Carrier Grade Enterprise Ethernet Network PBB-TE Ethernet OAM • IEEE 802. 1 ah PBB (MAC in MAC) • Secure Customer Separation • Service/Tunnel Hierarchy • Reduced Network State • IEEE 802. 1 Qay Ethernet Tunneling • Deterministic Service Delivery • Qo. S & Traffic Engineering • Resiliency & Restoration • Connectivity / Service Checks • ITU Y. 1731 Performance Metrics • Complete Fault Management • 802. 1 ag © Ciena Confidential and Proprietary 16

Performance Monitoring and Connectivity Fault Management © Ciena Confidential and Proprietary 17

Maturing Ethernet OAM into a Transport Technology Fault Management Functions Y. 1731 CCM Continuity Check P LBM/LRM Loopback P LTM/LTR Link Trace P AIS Alarm Indication Signal P RDI Remote Defect Indication P LCK Locked Signal P TST Test Signal P MCC Maintenance Comms. Channel P VSM/EXM Vendor/Experimental OAM P Performance Management Functions Y. 1731 FLR Frame Loss Ratio P FD Frame Delay P FDV Frame Delay Variation P 802. 3 ah (2005) Link Management Functions Discovery Link Monitoring Remote Failure Detect Rate Limiting Remote Loopback 802. 1 ag P P P O O O O 802. 1 ag O O O A Partial List of Completed and Evolving Standards § © Ciena Confidential and Proprietary IEEE 802. 1 Qay for PBB-TE – Connection Oriented Ethernet § IEEE 802. 3 ah EFM defines link level diagnostics and OAM § ITU Y. 1731 “OAM functions and mechanisms for Ethernet based networks” § MEF 10 and Y. 1731 describe Packet PM § MEF 16 describes Ethernet. Local Management Interface (LMI) ITU G. 8031 “Ethernet Protection Switching” § draft-fedyk-gmpls-ethernet. PBB-TE-01. txt for Control Plane Network planning: Bandwidth resources & traffic placement Fault sectionalization & propagation mechanisms IEEE 802. 1 ag “Connectivity Fault Management”, a subset of Y. 1731 § Traffic Engineering for deterministic bandwidth utilization Performance monitoring & statistics collection § MEF UNI and LMI E LMI Status E-LMI VLAN mapping E-LMI BW Admission MEF-ENNI Remote Loopback True Ethernet transport must maintain important functions from the TDM Transport Environment 18 Trace & loopback facilities Local Link Management Control plane for automated end-to-end provisioning and resiliency

PBB / PBB-TE management 802. 1 ag Properties à 802. 1 ag has the concept of maintenance levels (hierarchy). This means that OAM activity at one level can be transparent at a different level. à 802. 1 ag has clear address and level information in every frame. When one looks at an 802. 1 ag frame, one knows exactly à Where it originated from (SA MAC) à Where is it going (DA MAC) à Which maintenance level is it à What action/functionality does this frame represent. à Design Inherently address the OAM aspects for MP 2 MP connectivity (e. g. VLANs) © Ciena Confidential and Proprietary 19

The New Ethernet OAM Standards-based IEEE 802. 1 ag and ITU Y. 1731 Maintenance End Point = MEP Maintenance Intermediate Point = MIP 802. 1 ag Maintenance levels/hierarchy àContinuity Check (Fault) àMulticast/unidirectional heartbeat àLoopback – (MEP/MIP Fault Connectivity) àUnicast bi-directional request/response MEP MIP MEP àTraceroute (MEP/MIP Link Trace - Isolation) àTrace nodes in path to a specified target àDiscovery àService (e. g. all PEs supporting common service instance) àNetwork (e. g. all devices common to a domain) àPerformance Monitoring àFrame Delay Variation àFrame Loss Conceptually: -monitor the trunk or the service … or both Service 802. 1 ag Trunk 802. 1 ag © Ciena Confidential and Proprietary Built-in and on-switch 20

Carrier Ethernet Technology and Standards Update PBB/PBB-TE/E-SPRing G. 8032/PLSB and MPLS/VPLS/HVPLS/MPLS-TP Presented by: Rick Gregory Senior Systems Consulting Engineer May 25, 2011 © Ciena Confidential and Proprietary 21

Provider Backbone Bridging (PBB) IEEE 802. 1 ah © Ciena Confidential and Proprietary 22

Provider Backbone Bridge Introduction à IEEE 802. 1 ah is the Provider Backbone Bridge standard Payload C-VID S-V DA SA I-SID B-VID B-DA B-SA à Also known as Mac In Mac (Mi. M) encapsulation à PBB solves several of today’s Ethernet challenges à Service Scalability – up to 16 millions VPNs à Customer Segregation – Overlapping VLANs supported à MAC Explosion – Customer MAC addresses only learned at edge à Security – Customer BPDUs are transparently switched 802. 1 ah Provider Backbone Bridges © Ciena Confidential and Proprietary 23

Ethernet Frames…Before and After Payload Ethertype C-VID Payload Ethertype VID S-VID Ethertype SA DA I-SID 802. 1 basic SA = Source MAC address DA = Destination MAC address VID = VLAN ID C-VID = Customer VID S-VID = Service VID I-SID = Service ID B-VID = Backbone VID B-DA = Backbone DA B-SA = Backbone SA © Ciena Confidential and Proprietary 802. 1 Q tagged VLAN 802. 1 ad Qin. Q Provider Bridge Pre-existing (unchanged) New (backbone) Ethertype B-VID Ethertype B-SA B-DA 802. 1 ah MACin. MAC PBB 24

802. 1 ah PBB Encapsulation Header as used by PBB-TE B-SA MAC B-DA MAC Backbone Destination MAC address Backbone Source MAC address Field Tunnel Ethertype 0 x 88 A 8 B-TAG P D C E P I D A Service Ethertype 0 x 88 C 8 B-VID I-TAG P C P D R R E E E I-SID I S 1 S 2 58 Bit Tunnel Address Size Value Backbone-DA 6 bytes Tunnel destination MAC address. This must be a Unicast address only. Multicast MAC addresses are not allowed to be specified for this field. Backbone-SA 6 bytes Tunnel source MAC address used to identify this node in the network. B-TAG Ether-type 2 bytes 0 x 88 A 8 (default) B-VID 12 bits Tunnel VID (802. 1 Q compliant). B-TAG DEI 1 bit Drop Eligibility Indicator: 1=Drop eligible, 0=Not drop eligible B-TAG PCP 3 bits Tunnel Priority Code Point (0 -7) I-SID 24 bits Service identifier (1 – 16 million) I-TAG Ether-type 2 bytes 0 x 88 C 8 (default) RES 1 2 bits Don’t care RES 2 2 bits Don’t care I-TAG DEI 1 bit Drop Eligibility Indicator: 1=Drop eligible, 0=Not drop eligible I-TAG PCP 3 bits © Ciena Confidential and Proprietary Service Priority Code Point (0 -7) 25 S A

PBB: Solving Current Ethernet Challenges: à Service Scalability à Customer Segregation à MAC explosions, Broadcast Storms à Learning, Forwarding, Flooding Control Up to 16 million service instances using 24 bit service ID ISID Overlapping V-LANs supported Stops MAC Explosions and Broadcast Storms at MAC-in -MAC Demarcation Point Customer MAC is completely separate from Backbone MAC Architected to build E-LAN, E-Tree and E-Line services © Ciena Confidential and Proprietary 26

Provider Backbone Bridging With Traffic Engineering (PBB-TE) IEEE 802. 1 Qay © Ciena Confidential and Proprietary 27

PBB-TE (IEEE 802. 1 Qay) MPLS Services (RFC 2547 VPN, PWs etc. ) Ethernet Services (EVPL, ELAN, ELINE, Multicast) PBB-TE > Keep existing Ethernet, MPLS…FR/ATM…ANY & ALL services > Capitalize on Ethernet as transport for significant savings > Existing network-friendly solution! © Ciena Confidential and Proprietary 28

PBB-TE PBB E-LINE Traffic engineered PBB-TE trunks PBB Ethernet Metro E-LINE à P 2 P traffic engineered trunks based on existing Ethernet forwarding principles à Reuses existing Ethernet forwarding plane à Simple L 2 networking technology à Tunnels can be engineered for diversity, resiliency or load spreading à 50 ms recovery with fast IEEE 802. 1 ag CFM OAM © Ciena Confidential and Proprietary 29

PBB-TE Solving Current Ethernet Challenges: à Customer Segregation Full segregation in P 2 P model End to End TE With Qo. S & 50 ms recovery à Traffic engineering à Spanning Tree challenges: à Stranded bandwidth à Poor convergence Disable STP No blocked links Fast 802. 1 ag convergence à MAC explosions à Security MAC Explosions Eliminated Backbone MAC is Completely Different Than Customer MAC © Ciena Confidential and Proprietary 30

Provider Link State Bridging (PLSB) IEEE 802. 1 aq © Ciena Confidential and Proprietary 31

Introducing…. PLSB à PBB-TE is a trivial change to the Ethernet dataplane that has huge Benefits à Explicit enforcement of configured operation à Ability to have non STP based VLANs à Similarly PLSB requires a further trivial change with huge Benefits à Adding loop suppression to make Ethernet fit for a distributed routing system à PBB-TE, PLSB and existing Ethernet control protocols can operate side-byside in the same network infrastructure à Consequence of ability to virtualize many network behaviors on a common Ethernet base…. © Ciena Confidential and Proprietary 32

PLSB Approach à If Ethernet is going to be there…. use it! à Take advantage of Ethernet’s more capable data plane à Virtual partitions (VLANS), scalable multicast, comprehensive OAM à PLSB uses a Single (1) Link State Control Plane protocol – IS-IS à IS-IS topology and service info (B-MAC and I-SID information) à Integrate service discovery into the control plane à PLSB nodes use link state information to construct unicast and per service (or I-SID) multicast connectivity Combines well-known networking protocol with well-known data plane to build an efficient service infrastructure © Ciena Confidential and Proprietary 33

VPLS Operation Required for Auto-Discovery Separate RR topologies (to help scale) Eases burden of statically managing VSI PWE’s Signal PWEs VPN Protocols Typical VPLS Implementation: Base LDPs: build LSP tunnels Redundant to IGP (same paths) Base IGP: Topology Required for network topology knowledge Physical Links Link layer headers striped off, label lookup per node © Ciena Confidential and Proprietary Tunnel LSP Protocols N 2 manual session creation BGP-AD E-LDP or RSVP-TE IGP (IS-IS or OSPF) SONET, SDH, Ethernet, etc… VPLS CONTROL PLANE 34

PLSB Operation PLSB Implementation: Tunnel + VPN Protocols One IGP for Topology & Discovery PLSB (IS-IS) Ethernet -One protocol now provides - Auto-discovery - Fast fault detection - Network healing - Shortest path bridging - Intra-AS only Link State Protocol - Dijkstra's algorithm for best path - No VSI awareness required at Edge - Once Standardized Ciena could deploy - Own I. P. from MEN acquisition - Target IEEE 802. 1 aq Ratification 2 H 2011 Physical Links: - Link layer headers reused as a label lookup through every node Minimizing control plane = Minimized complexity = Reduced cost © Ciena Confidential and Proprietary 35

PPB/PBB-TE and PLSB Delivers E-LAN Any to Any E-LINE Point to Point CESD E-TREE Point to Multi-Point CESD Characteristics: PLSB – 200 -500 ms resiliency PBB-TE – 50 ms resiliency Optimized per service multicast Feature Rich OAM SLA and Service Monitoring Latency Monitoring No Spanning Tree Protocol Value: Simplest Operations Model Less Overhead and Network Layering Most Cost Effective Equipment Efficient Restoration © Ciena Confidential and Proprietary 36

Ethernet Shared Ring (E-SPRing) ITU G. 8032 © Ciena Confidential and Proprietary 37

G. 8032 Objectives and Principles à Use of standard 802 MAC and OAM frames around the ring. Uses standard 802. 1 Q (and amended Q bridges), but with x. STP disabled. à Ring nodes supports standard FDB MAC learning, forwarding, flush behaviour and port blocking/unblocking mechanisms. à Prevents loops within the ring by blocking one of the links (either a pre-determined link or a failed link). à Monitoring of the ETH layer for discovery and identification of Signal Failure (SF) conditions. à Protection and recovery switching within 50 ms for typical rings. à Total communication for the protection mechanism should consume a very small percentage of total available bandwidth. © Ciena Confidential and Proprietary 38

ITU G. 8032 Ethernet Rings a. k. a. E-SPRing (Ethernet Shared Protection Rings) E-SPRing Values • • • Efficient connectivity (P 2 P, multipoint, multicast) Rapid service restoration (<50 msecs) Server layer technology agnostic (runs over Ethernet, OTN, SONET/SDH, etc…) Client layer technology agnostic (802. 1 (Q, PBB, PBB-TE), IP/MPLS, L 3 VPN, etc…) Fully Standardized (ITU-T SG 15/Q 9 G. 8032) Scales to a large number of nodes and high bandwidth links (GE, 10 G, 40 G, 100 G) E-Line, E-LAN, E-Tree Major Ring Sub Ring Fault Sub Ring Deterministic 50 ms Protection Switching © Ciena Confidential and Proprietary Full service compatibility Sub Ring Multi-Layer Aggregation with Dual Homing Grow ring diameter, nodes, bandwidth 39

The Ciena G. 8032 Solution FORWARDING PLANE CONTROL PLANE • Sub-50 ms protection for E-LINE, E-TREE, and E-LAN services CONTROL PLANE • Guarantees loop freeness with prevention of frame duplication and reorder service delivery • Utilizes existing IEEE defined FORWARDING PLANE Bridging and IEEE 802. 3 MAC • Supports IEEE 802. 1 Q, 802. 1 ad, and 802. 1 ah MANAGEMENT PLANE • Ciena G. 8032 solution MIB • Generic Information Model • Supports Ethernet OAMPLANE (802. 1 ag, MANAGEMENT Y. 1731) fault and performance management • Operator commands (e. g. , manual/force switch, DNR, etc. ) STANDARDIZED • • • ITU-T Q 9/15 G. 8032 (ERP) IEEE STANDARDIZED 802. 3 MAC IEEE 802. 1 Q, 802. 1 ad, 802. 1 ah Ethernet OAM IEEE 8021. ag Ethernet OAM ITU-T Y. 1731 Ciena PORTFOLIO NETWORKING • Carrier Ethernet: 318 x, 3190, 3911, 3916, 3920, 3931, Ciena 3940, 3960, PORTFOLIO 5140, 5150 • Transport: OME 6500, OM 5 K, OME 6110/6130/6150 © Ciena Confidential and Proprietary SCALABLE • Physical/server layer agnostic • Supports. SCALABLE heterogeneous rings • Leverages Ethernet BW, cost, and time-to-market curve (1 Gb. E 10 Gb. E 40 Gb. E 100 Gb. E) • Dedicated rings • Ring interconnect via shared node NETWORKING and dual node • Dual-homed support to provider network technologies (e. g. , PBB, PBB-TE, MPLS, etc. ) 40

W B iu rs i e ln e s s Example G. 8032 Network Applications B S a e cr kv i h a c u e ls Metro Packet Transport N x T 1/E 1 s CO Metro/Collector G. 8032 Access G. 8032 Metro/Collector G. 8032 T 1/E 1 s Data PSTN Ethernet BSC Metro Packet Transport P A D r c. S Ethernet PBX Metro/ T 1/E 1 s c. Li Collector G. 8032 v. Branch Office #2 e a s. A Ethernet Access t sg G. 8032 T 1/E 1 s e PBX g Metro Packet Transport r Branch Office #3 Ethernet B e Other Core Technology u g T 1/E 1 s © Ciena Confidential and Proprietary PBX i a tl T 1/E 1 s PBX Data RNC Metro Packet Transport Ethernet T 1/E 1 s Voic e Other Core Technology Branch Office #1 Standalone G. 8032 PBX RNC Access G. 8032 -– Data Ethernet Voic e Ethernet HQ Branch Office #2 BSC PBX Branch Office #3 Branch Office #1 HQ Data Ethernet PSTN Metro Core Standalone G. 8032 LAG HQ Ethernet Data Ethernet PSTN 41

General G. 8032 Concepts © Ciena Confidential and Proprietary 42

What is a Channel Block? Blocking Port à A Channel block can be an ingress/egress rule A B placed on a G. 8032 node port à The Channel block rule specifies that any traffic with a VID received over this port within a given C F VID space should be discarded à NOTE: The Channel block function prevents E D traffic from being forwarded by the G. 8032 node, however, it does not prevent traffic from being received by Higher Layer Entities (e. g. , G. 8032 Engine) on that node à Each G. 8032 ringlet needs at least a single channel block installed © Ciena Confidential and Proprietary Channel Block Function 43

What is a Ringlet (a. k. a. Virtual Ring)? Ringlet 2 à A Ringlet is a group of traffic flows over the ring that share a common provisioned channel Ringlet 1 block à NOTE: It is assumed that each traffic flow has a VLAN associated with it à The traffic flows within a Ringlet is composed of à A single ringlet control VID (R-APS VID) à A set of traffic VIDs à A group of traffic flows over the ring can be identified by a set of VIDs à Multiple Ringlets on a given Ring can not have overlapping VID space © Ciena Confidential and Proprietary 44

Please view in animation mode G. 8032 E-SPRing Failure/Restoration 1 A 2 B C F E A B E D a) Normal configuration D b) Ring span failure occurs 3 4 A B A C F E D c) LOS detected d) Port blocking applied e) APS message issued © Ciena Confidential and Proprietary B C F R-APS messages E D R-APS messages f) R-APS causes forwarding database flush g) Ring block removed 45

V A Recovery Events F VI B C R-APS(NR) E WTR A F R-APS(NR, RB) E C D 11. When WTR expires, RPL block installed, Tx R-APS(NR, RB) 12. Nodes flush FDB when Rx R-APS(NR, RB) 13. Nodes remove port block when Rx R-APS(NR, RB) © Ciena Confidential and Proprietary C D 10. When RPL owner Rx R-APS(NR), it starts WTR timer. VIII B B R-APS(NR) E Guard Timer 8. Ring span recovery detected 9. Tx R-APS(NR) and start Guard Timer VII F D Guard Timer A A B C F E D 14. Normal configuration 46

G. 8032 Product Specifications © Ciena Confidential and Proprietary 47

G. 8032 E-Spring Interconnections Phase 1 a Standalone Ring E-SPRing If each ring is different Virtual Switch E-SPRing 1 Standalone Rings, LAG interconnect E-SPRing 1 Phase 1 c Phase 1 b E-SPRing 2 Phase 2 d Dual-Homed Rings (Major and Minor rings) E-SPRing 1 E-SPRing 2 e Phase 2 Dual-Homed Ring E-SPRing © Ciena Confidential and Proprietary Dual Homing 48

Phase 2 Availability Dual-Homed Rings (Major and Minor rings) are not supported in SAOS 6. 8 Chaining Rings and R-APS Protocol à There can be only one R-APS session running for a given VID Group on a ring span. à Major-Ringlets and Sub-Ringlets are used to chain rings. à On a Sub-Ringlet, the provisioned block for the data path is at the RPL owner (or on each side of a link fault), and the control path ALWAYS has its blocks where the Sub. Ringlet is open. G Data Path example A B C D © Ciena Confidential and Proprietary G I F Major. E E Ringlet Sub. Ringlet H J Control Path example A A I F Major. E E Ringlet B Sub. Ringlet C H D 49 J

G. 8032 Terms and Concepts à Ring Protection Link (RPL) – Link designated by mechanism that is blocked during Idle state to prevent loop on Bridged ring à RPL Owner – Node connected to RPL that blocks traffic on RPL during Idle state and unblocks during Protected state à Link Monitoring – Links of ring are monitored using standard ETH CC OAM messages (CFM) à Signal Fail (SF) – Signal Fail is declared when ETH trail signal fail condition is detected à No Request (NR) – No Request is declared when there are no outstanding conditions (e. g. , SF, etc. ) on the node à Ring APS (R-APS) Messages – Protocol messages defined in Y. 1731 and G. 8032 à Automatic Protection Switching (APS) Channel - Ring-wide VLAN used exclusively for transmission of OAM messages including R-APS messages © Ciena Confidential and Proprietary 50

Ring Idle State ETH-CC connected in a ring C. Logical topology has all nodes ETH-CC ETH-CC connected without a loop. D. Each link is monitored by its two adjacent nodes using ETH CC OAM messages E. Signal Failure as defined in Y. 1731, is trigger to ring protection à Loss of Continuity à Server layer failure (e. g. Phy Link Down) © Ciena Confidential and Proprietary RPL Owner ETH-CC figure) RPL ETH-CC B. ERP guarantees lack of loop by blocking the RPL (link between 6 & 1 in ETH-CC 2 1 3 4 RPL 6 5 Physical topology 2 1 6 3 4 5 Logical topology 51 ETH-CC A. Physical topology has all nodes

Protection Switching Link Failure A. Link/node failure is detected by RPL Owner RPL the nodes adjacent to the failure. B. The nodes adjacent to the R-APS(SF) report this failure to the ring R-APS(SF) failure, block the failed link and R-APS(SF) using R-APS (SF) message R-APS(SF) C. R-APS (SF) message triggers à RPL Owner unblocks the RPL à All nodes perform FDB flushing 2 1 3 4 2 1 6 3 4 5 D. Ring is in protection state E. All nodes remain connected in the logical topology. © Ciena Confidential and Proprietary RPL 6 2 3 5 Physical topology 1 RPL 6 4 5 2 1 6 3 4 5 Logical 52 topology

Protection Switching Failure Recovery A. When the failed link recovers, the traffic is kept blocked on the nodes adjacent to the recovered link R-APS(NR, RB) RPL R-APS(NR) C. When the RPL Owner receives RAPS(NR) message it Starts WTR timer D. Once WTR timer expires, RPL Owner blocks RPL and transmits RAPS (NR, RB) message E. Nodes receiving the message – perform a FDB Flush and unblock their previously blocked ports F. Ring is now returned to Idle state © Ciena Confidential and Proprietary R-APS(NR, R-APS(NR) RB) B. The nodes adjacent to the recovered link transmit R-APS(NR) message indicating they have no local request present RPL Owner R-APS(NR) 2 1 3 4 2 1 6 3 4 5 RPL 6 2 5 3 Physical topology 1 RPL 6 4 5 2 1 6 3 4 5 53 Logical topology

Multi Protocol Label Switching (Layer 3 IETF RFC 4364 / aka 2547 bis) (Layer 2 IETF RFC 2026 / Dry Martini) (Layer 2 IETF RFC 5654 / MPLS-TP) (MPLS/VPLS or PBB/PBB-TE) © Ciena Confidential and Proprietary 54

Ethernet Access – Network Choices à à Legacy Ethernet (No MEF compliance) Carrier Class Ethernet (MEF compliance) 1. Connection-less Ethernet à 802. 1 Q or 802. 1 ad or 802. 1 ah: VLANs 2. Connection Oriented Ethernet à 802. 1 Qay (PBB-TE): VLANs à MPLS-TP: Traffic Engineered PWs over LSP 3. IP control plane based IP or MPLS VPNs à IP VPN: Ethernet over L 2 TPv 3 over IP à MPLS VPN: Ethernet PW or VLAN over LSP © Ciena Confidential and Proprietary 55

MPLS vs. Ethernet – Data Plane (+OAM) Packet transport IP/MPLS Service Edge & Core Metro access & aggregation MPLS metro network à L 2 (VPLS/VPWS, MPLS-TP): forward Ethernet frames over Ethernet PW in MPLS LSP over Ethernet port à L 2: forward Ethernet frames over Ethernet EVCs over Ethernet port à Fewer data planes and OAM levels – Ethernet Service and Network/Link à Simpler hw/sw for >40% lower cost 2 à IP awareness for dataplane behavior but no need for OAM at IP layer à Multiple, varied data planes: IP, PW, LSP, Ethernet à Less complex OAM using 802. 1 ag and Y. 1731 for Ethernet service and network/tunnel layers à complex hw/sw interactions resulting in higher cost 1 à complex OAM à MPLS-TP LSP OAM yet to be defined Reid, Willis, Hawkins, Bilton (BT), IEEE Communications Magazine, Sep 2008 2 (40 -60% less) Mc. Kinsey & Co. , Jan 2008; (40% less) CIMI Corp, Jul 2008 © Ciena Confidential and Proprietary “Application” “Service” Management Ethernet (PBB-TE) metro network à L 3 (IP/MPLS): terminate Ethernet & forward IP frames over IP PW in MPLS LSP over Ethernet port 1 Subscriber Management IP, Ethernet PW LSP Ethernet Complex à Ethernet (PB, PBB) can enable Pt-Mpt and Mpt, in addition to Pt-Pt Service Network IP, Ethernet VLAN (EVC) Data Plane Ethernet Simpler 56

MPLS vs. Ethernet – Control Plane (+OAM) MPLS metro network Subscriber Management Packet transport IP/MPLS Service Edge & Core Metro access & aggregation “Application” “Service” Management Ethernet (PBB-TE) metro network à Complex link-by-link label swapping – inherent source of unreliability 1 à Complex L 3 control plane for PW/LSP signaling/routing (& PW stitching at core edge) à Complete, global Ethernet header à BEB’s SA/DA+BVID for tunnel à No label switched path setup needed à E 2 E visibility, connectivity verification à PW/LSP labels: LDP or BGP à Simpler L 2 control plane for discovery only à LSP setup: RSVP-TE (signaling), OSPF -TE (routing) à No distributed routing/signaling needed à MPLS-TP can avoid L 3 control plane; use complex NMS-based link-by-link LSP config instead à Complex protocol couplings resulting in processing complexity and higher opex 3 à Metro hub-&-spoke (vs. core mesh) affords explicit failure mode config 4 à <=9 such modes in large metro à 12% lower opex (future: up to 44%)4 à Simpler OAM: reliable & lower opex 1, 3 Ethernet provides just enough control & data plane functionality to meet all service needs while containing cost and complexity 3 4 © Ciena Confidential and Proprietary Seery, Dunphy, Ovum-RHK, Dec 2006 CIMI Corp. , Netwatcher newsletter, Jul 2008 57

PBB/PBB-TE or VPLS/MPLS? Caution: Unscientific poll results Ethernet is the new paradigm Deterministic Transport with OAM&P Light Reading webinar: Building Converged Services Infrastructure http: //www. lightreading. com/webinar_archive. asp? doc_id =28415 PBB-TE perceived to offer cost advantages CO-Ethernet is one option Light Reading webinar: PBB-TE’s Winning Ways http: //www. lightreading. com/webinar_archive. asp? doc_id =28511 © Ciena Confidential and Proprietary Light Reading webinar: Building Converged Services Infrastructure http: //www. lightreading. com/webinar_archive. asp? doc_id =28415 58

PB/PBB-TE and MPLS Tunnel Inter-working Ingress and egress virtual interfaces provide greatest flexibility and interoperability with existing and emerging technologies à Dual-tag push/pop/swap enables multi-protocol interworking (e. g. , PBB-TE, MPLS) à Standard IEEE and popular Cisco-proprietary protocol handling enable robust L 2 VPNs IEEE and Cisco proprietary L 2 control frame tunneling Access / Aggregation MEF UNI Metro Q-in-Q or MPLS H-VPLS PBB/PBB-TE or PBB/TE Core Dual tag push/pop/swap EVC Q-in-Q or PBB-TE Tunnel MPLS LSP Q-in-Q or PBB-TE Tunnel EVC (PW) Seamless interworking between PB (Q-in-Q), PBB/PBB-TE and MPLS simplifies the handoff between domains © Ciena Confidential and Proprietary 59

PBB-TE provides cost-effective robust packet transport, but why not combine that with IP/Ethernet service intelligence on one node? à i. e. IP Routing isn’t deterministic, but it has useful service layer functions – multicast, differentiated services treatment à Why not use IP/MPLS nodes? à IP for services àMulticast àL 3 Prioritization Because Carrier Ethernet Switches are >40% lower cost than IP/MPLS Carrier Ethernet Switch/Routers (40 -60% less) Mc. Kinsey & Co. , Jan 2008 (40% less) CIMI Corp, July 2008 à MPLS for services àVPLS: Mpt-Mpt àVPWS: Pt-Pt à MPLS-TP for transport àPt-Pt Need a Carrier Ethernet Switch that combines “IP/service-aware” switching while retaining carrier-grade packet transport qualities! © Ciena Confidential and Proprietary 60

Ethernet data plane Functions PBB-TE / PBB MPLS-TP Ethernet Aggregation Native Ethernet (E-o-E) with less overhead. Scalability with 24 -bit I-Sid Same as MPLS. Need PW & tunnel headers (E-o-PW/LSP-o-E). Can nest aggregation layers. May help with scaling Forwarding labels Transparency & Isolation Unique end-to-end: DA+B-Vid Same as MPLS. Scales as # of endpoints (nodes) + service classes, if any. (tunnel) labels can be per hop or end-to-end Separate MAC address space (provider/Backbone vs. customer) Transparent transport for Ethernet clients MAC learning can be enabled for PBB-TE’s vid space Topology May scale as # of links + service classes, if any. Need coordination across links along a path B- No MAC learning defined but possible ELINE (Point-Point): Yes ELINE (Point-Point): : Yes ETREE (Point- Multipoint): : Yes ELAN (Multipoint): Needs either Pt-Mpt or full mesh of Pt. Pt LSP tunnels. May use VPLS model but need complex MPLS control plane & also requires either Pt-Mpt or full mesh of Pt-Pt PW’s. Layering, Partitioning, Hierarchy Simple: Backbone MAC address space w. r. t. Customer MAC address space Complex: additional PW/LSP layers. Nested tunnels can introduce OAM/provisioning complexity Peering MEF’s ENNI and Co. S IA are work in progress for service level. IEEE already provides interface and link models Work in progress. Peering with MPLS network may mean complex MPLS control plane. Also, need PW signaling end-to-end. “other” services Adjunct platforms where needed to achieve ATM/FR IW. Possible to use PWs if necessary PW capability along with protocol zoo for ATM/FR IW © Ciena Confidential and Proprietary 61

Ethernet Management plane OAM PBB-TE / PBB MPLS-TP Reuse 802. 1 ag/Y 1731. Use 802. 1 ag/Y. 1731 for Ethernet EVC (a) CCM needs to use unicast DA (allowed by PW/LSP is work in progress 802. 1 ag and already defined in Y. 1731). Also, MIPs need to intercept if DA is of MIP. (b) LBM/LBR in most cases, will use same VID in forward and reverse direction and so no issues. (c) LTM/LTR is possible if MIPs can intercept/ignore frames as needed. New TLV with MIP DA to be defined End-to-End visibility MEG levels Protection I-Sid for service (EVC) PW/LSP is work in progress DA+B-vid for tunnel Less oam levels: Ethernet customer flow, Ethernet More oam levels: Ethernet customer flow, Ethernet EVC, operator and transport / link EVC, LSP tunnel(s), operator and transport / link End-to-end (1+1, m: n), IEEE Link Aggregation Transport network like using APS for 1+1/m: n G. 8031/G. 8032 PW and LSP level, span/segment/end-to-end may use fast re-route if control plane present © Ciena Confidential and Proprietary 62

MPLS Protocols (net-net) à MPLS Provides: à Virtually unlimited service scalability à Eliminates MAC table explosions à 50 ms resiliency à Requires RSVP-TE + FRR everywhere à OAM relies on the control plane à Traffic Engineering à Limited performance monitoring à Bandwidth guarantees à Requires DS-TE for multiple bandwidth pools à MPLS Requires à IGP+TE à RSVP-TE PBB-TE eliminates these protocols à FRR à BFD à PWE 3 control plane à Increased OPEX à Increased CAPEX à VPLS control plane à H-VPLS/ MS-PW for scalability à MPLS forwarding plane upgrades à MPLS control plane server cards © Ciena Confidential and Proprietary 63

PBB/PBB-TE Protocols (net-net) à Carrier Ethernet Service Delivery Provides: à Virtually unlimited service scalability à Eliminates MAC table explosions à 50 ms resiliency à Service OAM à Traffic Engineering à Bandwidth guarantees à Carrier Ethernet Delivers: à Sub 50 ms recovery with PBB-TE à Deterministic and scalable in-band OAM à Standardized performance monitoring à PBB-TE provides traffic engineering and bandwidth guarantees à Provider Backbone Bridging with TE à IEEE 802. 1 ag, ITU Y. 1731 © Ciena Confidential and Proprietary à Standardized Ethernet forwarding and OAM à No changes to the hardware à No huge learning curve à Still just forwarding Ethernet à Enterprise demands Simplicity 64

Positioning Carrier Ethernet to Enterprise Customer © Ciena Confidential and Proprietary 65

Connection Oriented Ethernet Packet Access Comparison Key aspects Connectionless IP VPNs MPLS-TP Ethernet Interoperability - Ethernet àMEF Ethernet UNI/ENNI àMEF Ethernet Services Interoperability - other Need IWF, dry Martini àMPLS NNI àATM/FR/TDM/MPLS UNI (Work In Progress) Need IWF (L 2 TP, GRE) Scalability àNetwork & Services à(Pt-Pt & MPt) Reliability à 50 -100 msec protection àDisjoint Working/Protect paths Manageability àFault sectionalization àService & Network OAM/PM L 2 © Ciena Confidential and Proprietary Need IWF, dry Martini FRR 1+1 TBD àGuaranteed rate, latency/jitter/loss Low Cap. Ex and Op. Ex L 3 Transparency Deterministic Perf/Qo. S àAddress & control protocols PBB/PBB-TE 66

Positioning Carrier Ethernet to Enterprise VPLS/H-VPLS/MPLS 1. PBB/PBB-TE/E-SPRing PBB-TE/PBB/E-SPRing Forwarding Plane Only 1. Multiple VPN & Tunneling Control Plane Protocols 2. Optimized for Large Carrier Customers with MPLS backbone 2. Optimized for Enterprise Customers looking to minimize OPEX and IP/MPLS knowledgeable and trained Engineering Staff CAPEX spend (low cost plug & play Network) 3. CCIE type skills Not Required (+ Ethernet and SONET knowledgeable 3. Requires Extensive Engineering 4. 2 to 3 9 s SLAs Ethernet Service Delivery 5. Second/s to Sub-second Restoration (R-STP/FRR) 6. Q-in-Q Stacked VLANs 4096 maximum 7. High priced MPLS HW and SW based Routers 8. Requires strong L 3/IP/MPLS Knowledge/Config 9. Locked into a Vendor’s MPLS Products/Solution 10. Desire to fill unused capacity 11. Higher % sales of L 3 VPN 12. Solving core not aggregation 13. Desire protocols to provision 14. Techs trained for L 3/IP config 12. 16 Million VPNs (IEEE 802. 1 ah Mac-in-Mac), PBB only 15. Difficult to deploy @ customer 13. Low CAPEX and OPEX Economics Engineers Get it !) 4. Need to Lease Fiber (Typically unless you already own) 5. High Reliability, Resiliency, Scalability, and Simplicity 6. 4 to 5 9 s SLAs Ethernet Service Delivery 7. Sub 50 ms Protection Switching / Restoration (IEEE 802. 1 ag) 8. Ethernet is the single End to End Protocol Language Spoken 9. Excellent OAM (Y. 1731 and 802. 1 ag) – Jitter/Latency 10. Stop MAC/VLAN explosions and Broadcast Storms (Separate MAC Tables – Customer LAN & Backbone) 11. Minimizes MAC Learning and Distribution/Forwarding (True MAC learning Demarcation between LAN and MAN/WAN) 1. Field techs not trained 14. SONET Like Skill sets to Configure and Manage Network 2. Higher $$$ CPE 15. Ethernet Open Standards – 3 rd Party Vendor Interop benefits 3. More complex configuration 16. Transport over GE Microwave © Ciena Confidential and Proprietary 67

Carrier Ethernet Service Delivery Summary à Increased Simplicity with universally acknowledgeable Ethernet MAC • Ethernet MAC is the single End to End Protocol Language (No Multi-Protocol Translation, Ethernet only) à Improved Reliability with IEEE 802. 1 ag • Sub 50 ms Protection Switching / Restoration (IEEE 802. 1 ag Network Continuity Message that is tunable) à Qo. S (Quality of Service) without Control Plane Complexity with IEEE 802. 1 Qay PBB-TE • Traffic engineered tunnels with B-MAC’s B-VID pcp (p-bit) Classification Prioritization à Superior OAM with IEEE 802. 1 ag and ITU Y. 1731 • Monitor Performance End to End (Varying Delay-Jitter/Delay-Latency/Loss) in and out of Network at Layer 2 • Loop Back Message / Link Trace Message (SONET like) Loopback troubleshoot testing on Ethernet à Enhanced Network Control applying IEEE 802. 1 ah MACin. MAC Backbone • Stop MAC/VLAN explosions and Broadcast Storms • Minimize MAC Learning and MAC Distribution (Separate MAC Demarc between LAN and MAN/WAN) à Massive Scalability with IEEE 802. 1 ah MACin. MAC Backbone Frames • 24 bit ISID delivers 16 Million VPNs (IEEE 802. 1 ah Mac-in-Mac) • Only learns and forwards based on Backbone MAC Addresses (LAN MAC learning stays in the LAN) à Lower OPEX and CAPEX plus Open Standards inter-operability benefits • Lower OPEX, SONET and/or Ethernet Engineering Skill sets/experience to Configure and Manage Network • Lower CAPEX, Open to inter-operate with “any” 3 rd Party Ethernet Products, Ethernet Price Points à Key Message to Customer • Ethernet Switch Where You Can • IP/MPLS Route Where You Must © Ciena Confidential and Proprietary 68

Carrier Ethernet Service Delivery Value Proposition 1. Scalable Ø Eliminate control plane restrictions Ø Deployable on Optical and Broadband NEs 2. Operationally Sound, Easier to Troubleshoot Ø Ø Ø Better OAM tools: 802. 1 ag vs. VCCV/LSP-PING Fewer Moving Parts: No IGP, MPLS signaling etc. Consistent Operations Model with PMO Easier transition of workforce Consistent use of Metro OSS systems 3. Number # 1 with 20% Market Share in the Layer 2 CEAD Ethernet over Fiber Market, “Light Reading July 14, 2010 www. lightreading. com/document. asp? doc_id=194390 4. SLA / Performance Measurement Built In Simplified Network Layering Ø Ethernet is the faceplate and network layer 5. Lower CAPEX Ø Ethernet based infrastructure that rides Ethernet cost curves © Ciena Confidential and Proprietary 69

Thank you ! (Q & A) © Ciena Confidential and Proprietary 70

G. 8032 Terms and Concepts à Ring Protection Link (RPL) – Link designated by mechanism that is blocked during Idle state to prevent loop on Bridged ring à RPL Owner – Node connected to RPL that blocks traffic on RPL during Idle state and unblocks during Protected state à Link Monitoring – Links of ring are monitored using standard ETH CC OAM messages (CFM) à Signal Fail (SF) – Signal Fail is declared when ETH trail signal fail condition is detected à No Request (NR) – No Request is declared when there are no outstanding conditions (e. g. , SF, etc. ) on the node à Ring APS (R-APS) Messages – Protocol messages defined in Y. 1731 and G. 8032 à Automatic Protection Switching (APS) Channel - Ring-wide VLAN used exclusively for transmission of OAM messages including R-APS messages © Ciena Confidential and Proprietary 71

G. 8032 Timers à G. 8032 specifies the use of different timers to avoid race conditions and unnecessary switching operations àWTR (Wait to Restore) Timer – Used by the RPL Owner to verify that the ring has stabilized before blocking the RPL after SF Recovery àHold-off Timers – Used by underlying ETH layer to filter out intermittent link faults àFaults will only be reported to the ring protection mechanism if this timer expires © Ciena Confidential and Proprietary 72

Controlling the Protection Mechanism à Protection switching triggered by à Detection/clearing of Signal Failure (SF) by ETH CC OAM à Remote requests over R-APS channel (Y. 1731) à Expiration of G. 8032 timers à R-APS requests control the communication and states of the ring nodes à Two basic R-APS messages specified - R-APS(SF) and R-APS(NR) à RPL Owner may modify the R-APS(NR) indicating the RPL is blocked: R-APS(NR, RB) à Ring nodes may be in one of two states à Idle – normal operation, no link/node faults detected in ring à Protecting – Protection switching in effect after identifying a signal fault © Ciena Confidential and Proprietary 73

Signaling Channel Information à ERP uses R-APS messages to manage and coordinate the protection switching à R-APS defined in Y. 1731 - OAM common fields are defined in Y. 1731. à Version – ‘ 00000’ – for this version of Recommendation à Op. Code – defined to be 40 in Y. 1731 à Flags – ‘ 0000’ – should be ignored by ERP 1 8 1 7 MEL 6 5 2 4 3 2 1 8 7 Version (0) 6 5 3 4 3 2 1 8 Op. Code (R-APS = 40) 7 6 5 4 3 2 1 8 Flags (0) 5 R-APS Specific Information (32 octets) . . … 37 4 7 6 5 4 3 2 TLV Offset (32) [optional TLV starts here; otherwise End TLV] last End TLV (0) Defined by Y. 1731 © Ciena Confidential and Proprietary Non-specified content Defined by G. 8032 74 1

R-APS Specific Information à Specific information (32 octets) defined by G. 8032 à Request/Status(4 bits) – ‘ 1011’ = SF | ’ 0000’ = NR | Other = Future à Status – RB (1 bit) – Set when RPL is blocked (used by RPL Owner in NR) à Status – DNF (1 bit) – Set when FDB Flush is not necessary (Future) à Node. ID (6 octets) – MAC address of message source node (Informational) à Reserved 1(4 bits), Status Reserved(6 bits), Reserved 2(24 octets) - Future development 1 8 7 6 5 Request /State 2 4 3 2 1 8 7 Reserved 1 6 5 3 4 3 2 1 8 7 Status R B D N F 6 5 4 4 3 2 1 8 Node ID (6 octets) Status Reserved (Node ID) Reserved 2 (24 octets) © Ciena Confidential and Proprietary 7 75 6 5 4 3 2 1

Items Under Study à G. 8032 is currently an initial recommendation that will continue to be enhanced. The following topics are under study for future versions of the recommendation: a) RPL blocked at both ends – configuration of the ring where both nodes Interconnected rings scenarios: shared node, shared links b) connected to the RPL control the protection mechanism c) Support for Manual Switch – administrative decision to close down a link and force a “recovery” situation are necessary for network maintenance d) Support for Signal Degrade scenarios – SD situations need special consideration for any protection mechanism e) Non-revertive mode– Allows the network to remain in “recovery” configuration either until a new signal failure or administrative switching f) RPL Displacement – Displacement of the role of the RPL to another ring link flexibly in the normal (idle) condition g) In-depth analysis of different optimizations (e. g. , FDB flushing) h) Etc. © Ciena Confidential and Proprietary 76