Presented by: CBNetworks Technical Support May 2008 Ethernet and Legacy Access over DSL

Ethernet and Legacy Access over DSL for TS2008 Slide F.ETH EFM Bonding GbE LA-110 F.ETH Branch IPDSLAM ATM LA-210 IPDSLAM Branch GbE Ethernet over DSL ASMi-54 SHDSL.bis RICi-4/8E1 RICi-16 SDH GbE STM-1/OC-3 10BT 100BT EoPDH GFP-VCAT Branch GFP Egate Branch RICi-E1 10BT Ethernet over PDH ADM MLPPP RICi-622GE Branch GbE STM-4/OC-12 RICi-155GE Branch GbE STM-1/OC-3 GbE Ethernet over SDH/SONET Headquarters ETX-202 F.ETH GbE Metro Ethernet ETX-202A Branch GbE Ethernet over Fiber Variety of Ethernet Access Solutions – Implementation Scenario Service Provider Packet Switched Network Extending the reach of the provider’s network over a variety of access technologies Consistent Ethernet service across different access technologies

Ethernet and Legacy Access over DSL for TS2008 Slide Agenda Agenda: ASMi-54 Concept + Applications LA-110 Concept + Applications LA-210 Concept + OAM Summary Appendix Road Maps LA Product Family Line LA-210 Flow Concept OAM – CC/LB/LT

Ethernet and Legacy Access over DSL for TS2008 Slide What is the Business Case? Strong growth of DSL subscribers ~200 million in 2007 expected to grow to 364 million in 2011* What are they used for? Internet hi-speed access (residential customers) Added value (residential market - video, gaming, etc.) Voice over IP services IP VPN services for business customers * Source: Infonetics Research, Broadband Aggregation Hardware and Subscribers Market Share and Forecasts 4Q07 We have the technology and the infrastructure which provide higher Bandwidth…. …what else can we do with it? Carrier & Utilities Market (Railways, Highways, CCTV) Leased line services (E1/T1, n x 64 kbps), FR Ethernet services for Business customers Cellular backhaul for 2G/2.5G and 3G networks

Ethernet and Legacy Access over DSL for TS2008 Slide Customer Premises IPDSLAM PBX E1 LA-110 ETH CO/POP TDMoIP Gateway IPmux Gmux GbE TDM Customer Premises PBX E1 LA-110 ETH SHDSL IPDSLAM SHDSL PSN Eth/IP/MPLS RNC IPDSLAM ASMi-54 LA-210 Node-B PSN Eth/IP/MPLS n x SHDSL Fast Ethernet GbE Fast Ethernet ETH & Legacy Over DSL

Ethernet and Legacy Access over DSL for TS2008 Slide Modem Type ETH Ports Other interfaces Max. Rate Max.wire s Power Supply EN – Stand. DIN Installation ETH Performance Metal Box Standard ASMi-521 PORT E1/T1/V35/X 21/RS M2W,4WAC/DC/24V Comply on S/A* Comply 4WVLAN priorityComplySHDSL ASMi-52L 1 or 4 PORTs E1/V354.6M2W,4WAC/DCN/A VLAN priorityN/ASHDSL ASMi-544 PORTS E1 – Phase M2W,4W,8WAC/DC/24VN/A Support on 2w & 4w VLAN priority /QOS Only 8WSHDSL.bis/EFM MP-2100, MP-4100, DXC-30, LRS-24 Central Solution MP-4100*, LRS-102 SHDSL Products Profile * ASMi-54C – beta Q3/08

Ethernet and Legacy Access over DSL for TS2008 Slide ASMi-54 – G.SHDSL.bis Technology ASMi-54 New SHDSL standard – TC-PAM 32 Enables 5.7Mbps over 2w Even higher rate over 8w with bonding ASMi-52 Standard SHDSL – TC-PAM 16 Enables 2.3Mbps over 2w No bonding ServicesLink Options 2w 4w 8w ETH ASMi Mbps 11.4 Mbps 22.8 Mbps ETH

Ethernet and Legacy Access over DSL for TS2008 Slide ASMi-54 – Phase 1 Management options Terminal, Telnet, ConfiguRAD, Out-of-band/In-band Ethernet port In-band dedicated VLAN to encapsulate management traffic WAN Protocol EFM bonding - enables each link to synch at different rate. Failure or addition of a link doesn't drop the whole group VLAN Mode Stacking/stripping based on 802.1D MAC,802.1Q VLAN Quality of service (QOS)on the DSL egress direction Fault Propagation From SHDSL to user interface Estimated Distance Estimated 5,696 kbit/s – 2.9 km - with cable Up to 22.8Mbps over 8 wires Ordering Options Plastic/Metal box/Rail Mount case Extended temperature option (-20˚C to +70˚C)

Ethernet and Legacy Access over DSL for TS2008 Slide ASMi-54 – Phase ETH ports with additional E1/T1 ports RADview support (RV-EMS-SW/TDM/PC 1.8) SHDSL.bis repeaters support: 2W, plastic – S-RPT 2W, metal IP-67 Outdoor – S-RPT/IP-67 4W, metal IP-67 Outdoor – S-RPT-4W 2w 4w 8w Four ETH ASMi Mbps 11.4 Mbps 22.8 Mbps E1/T1 Phase 2.0 Available !! Beta Q2/08

Ethernet and Legacy Access over DSL for TS2008 Slide Central Solution: LRS-102/ASMi-54 Card LRS-102 4U, 12 I/O System redundancy Central management Improved pricing 12 x 16W per ASMi-54 card High port density - 24 OP-108/106 modules Under customers validation ASMi-54 Card Stackable into LRS-102 and MP Supports up to 16 wires on the DSL line Interfaces: 8 E1 lines via DB-44 cable balanced 2 ETH 10/100 Base T ports 2 x power supplies 2 x Common Logic 12 I/O slots

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide ETH ASMi-54 Pumping Station ASMi-54 Point to Point Applications Winning Combination / Business Environment: Built-in Ethernet bridge High ETH performances 5.7 Mbps over 2-wire lines – estimated 2.9 km on 26AWG ASMi-54 Control Room CCTV 5.7 Mbps Four ETH E1/T1 Phase 2.0 Phase 1.0 Four ETH E1/T1 ASMi-54 SHDSL.bis Repeater ASMi-54 Phase 2.0 Phase 1.0

Ethernet and Legacy Access over DSL for TS2008 Slide Ethernet and E1 Range Extension over Copper using a Central Solution Key Benefits Powerful central site solution Low cost and simplicity High reliability (PS and main link protection) CP PBX POP SHDSL.bis n x FETH n x E1/T1 E1 SDH/ SONET ETH ASMi-54 LRS-102/MP-4100 IP/MPLS Beta Q3/08

Ethernet and Legacy Access over DSL for TS2008 Slide Customer Premises IPDSLAM PBX E1 LA-110 ETH CO/POP TDMoIP Gateway IPmux Gmux GbE TDM Customer Premises PBX E1 LA-110 ETH SHDSL IPDSLAM SHDSL PSN Eth/IP/MPLS RNC IPDSLAM ASMi-54 LA-210 Node-B PSN Eth/IP/MPLS n x SHDSL GbE Fast Ethernet ETH & Legacy over DSL

Ethernet and Legacy Access over DSL for TS2008 Slide Evolution of Ethernet and Legacy Service Delivery over DSL All the way ATM; Ethernet, E1, serial or FR services based on ATM LA-110 Legacy Core ATM Traditional DSLAM ATM ATM Ethernet PSN Core Ethernet, IP, MPLS Ethernet and legacy services over PSN using PWE IAD to DSLAM segment based on ATM Traditional DSLAM with Ethernet Uplink LA-110

Ethernet and Legacy Access over DSL for TS2008 Slide LA-110 Interfaces & WAN Protocols SHDSL 1,2 pairs or 4 pairs (IMA) Line coding:PAM16 Data rates up to 2.3 Mbps (2W) Data rates up to 4.6 Mbps (4W) Date rates up to 9.2 Mbps (IMA) ADSL ITU-T G.992 Annex A Line coding:Full DMT Line rate: 8/1 Mbps Chipset: Connexant WAN Interfaces E1/T1 ports (ATM or TDM) Control port Serial data interface (V.35, X.21) 10/100BaseT interface Bridge Router E1 ATM UNI G.703, G.704 Line rate: Mbps

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide Leased Line & LAN Services over ATM DSLAM SHDSL DSLAM LA-110 Site A E1 V.35 Router PBX LAN LA-110/IMA Router PBX LAN ETH 4*SHDSL ATM E1 V.35 ETH Site B Leased Line/CES Applications Serial (V.35/X.21) bit stream over ATM Unframed E1 over ATM Fractional E1/T1 over ATM E1/T1 to serial bit stream E1 UNI connection over ATM LAN Operating modes: Routing (Including Firewall, NAT DHCP) Bridging (Including full VLAN support)

Ethernet and Legacy Access over DSL for TS2008 Slide Frame Relay Services over ATM LAN LA-110 DSLAM LAN LA-110 Branch Office ATM DSLAM Central Office FRAD Frame Relay V.35/X.21 FRF.5 LA-110 DSLAM Customer B ATM Customer A FRAD FRATM FRF.8

Ethernet and Legacy Access over DSL for TS2008 Slide LA-110 version 3.5 New Features Support for Pseudowire for legacy service emulation over Packet- Switched Networks using IPDSLAMs Supported Services: Leased lines using TDM pseudowire PSTN access using TDM pseudowire Cellular backhaul using ATM and TDM pseudowire Frame Relay using HDLC or Frame Relay pseudowire Pseudowire standards TDM – CESoPSN, TDMoIP and SAToP ATM – ATMoPSN HDLC – HDLCoPSN FR – FRoPSN Clocking based on NTR Full SNMP agent allows RV-EMS or any standard management station to manage the device PSN Core Ethernet, IP, MPLS IPDSLAM Ethernet ATMEthernet LA Available for Beta

Ethernet and Legacy Access over DSL for TS2008 Slide Customer Premises IPDSLAM PBX E1 LA-110 ETH CO/POP TDMoIP Gateway IPmux Gmux GbE TDM Customer Premises PBX E1 LA-110 ETH SHDSL IPDSLAM SHDSL PSN Eth/IP/MPLS Leased Line over Packet Switched Networks CESoPSN or TDMoIP tunneling solution (PWE) On the receive side the jitter buffer stores the payload prior to play-out to the local TDM attachment circuit The size of the buffer is locally configured to accommodate the PSN-specific packet delay variation Clock recovery is based on NTR

Ethernet and Legacy Access over DSL for TS2008 Slide Customer Premises IPDSLAM PBX E1 LA-110 ETH CO/POP TDMoIP Gateway IPmux Gmux GbE TDM Customer Premises PBX E1 LA-110 ETH SHDSL IPDSLAM SHDSL PSN Eth/IP/MPLS RNC IPDSLAM ASMi-54 LA-210 Node-B PSN Eth/IP/MPLS n x SHDSL GbE ETH & Legacy Over DSL Fast Ethernet

Ethernet and Legacy Access over DSL for TS2008 Slide Evolution of Ethernet and Legacy Service Delivery over DSL IPDSLAM All the way ATM; Ethernet, E1, serial or FR services based on ATM LA-110 Legacy Core ATM Traditional DSLAM ATM ATM Ethernet PSN Core Ethernet, IP, MPLS Ethernet and legacy services over PSN using PWE IAD to DSLAM segment based on ATM Traditional DSLAM with Ethernet Uplink LA-110 PSN Core Ethernet, IP, MPLS All the way PSN, Ethernet and legacy services using PWE IAD to DSLAM segment based on Ethernet (EFM) IPDSLAM Ethernet Ethernet (EFM)Ethernet LA-210

Ethernet and Legacy Access over DSL for TS2008 Slide LA-210 Introduction G.SHDSL.bis EFM Ethernet Access device supporting rates of: 2wire – 5.7Mbps 4wire – 11.4Mbps 8wire – 22.8Mbps MEF certification MEF-9 Test suite for services at the UNI MEF-14 Test suite for Traffic Management E1/T1 ports Up to 4 Fast Ethernet Serial data interface (X.21, V.35) WAN interfaces SHDSL EFM (1,2 or 4 pairs) SHDSL ATM (1 or 2 pairs) Control port

Ethernet and Legacy Access over DSL for TS2008 Slide MEF Services Terminology Ethernet Private Line (EPL) Point-to-Point EVC Carrier Ethernet Network CE UNI CE UNI CE UNI ISP POP *UNI Internet *NNI NNI Port Based Service Multiplexed Ethernet UNI Multipoint-to-Multipoint EVC Carrier Ethernet Network CE UNI CE UNI CE UNI NNI Service Based Ethernet Virtual Private Line (EVPL) CE UNI CE UNI CE UNI ISP POP UNI Port Based UNI Ethernet Private Line (EPLAN) Ethernet Virtual Private Line (EVPLAN) Service Multiplexed Ethernet UNI CE UNI CE UNI CE UNI Service Based

Ethernet and Legacy Access over DSL for TS2008 Slide LA-210 Working Modes LA-210 is designed to deliver business-class Ethernet services, using two operational modes: Bridge mode VLAN aware/unaware VLAN stacking Supports 64 VLANs out of full range (1-4095) Static/Dynamic MAC learning with aging 1K of MAC entries Flows – customer traffic is mapped to the Ethernet flows (EVCs) using the following: Port-based Customer VLAN ID Customer VLAN priority DSCP IP Precedence

Ethernet and Legacy Access over DSL for TS2008 Slide LA-210 Flow Based Forwarding Model By CoS Step 6– Editing & Marking: 1.Editing=Adding SP- VLANEditing=Adding SP- VLAN 2.Marking=Adding SP-P.BitMarking=Adding SP-P.Bit Step 2–Flow Mapping: Defines members per flow Step 3–Assigning CoS: 1.Fixed per FlowFixed per Flow 2.CoS per ServiceCoS per Service Step 4–Assigning BW Profile: 1.CIR/EIRCIR/EIR 2.CBS/EBSCBS/EBS Step 5–Queues & Rate Limit: 1.Strict or WFQStrict or WFQ 2.Rate Limit per Q/SHDSL PortRate Limit per Q/SHDSL Port CoS per Flow Flow 1 = CoS 3 Policer per CoS CoS 3=BW profile 1 Flow 1 (EVC 1) CE-VLAN= 1 Flow 1 (EVC 1) CE-VLAN : 555 p.bit p.bit 4 Policer per CoS CoS 7=BW profile5 Flow 2 Up to 8 flows Policer per CoS CoS 4=BW profile3 Step 1–Flow Classification: 1.VLAN IDVLAN ID 2.P.BitP.Bit 3.DSCPDSCP 4.IP-PrecedenceIP-Precedence Editing Adding SP-VLAN Marking CE-P.bit  SP-P.bit UNINNI CoSQueuesST/WFQ mng5 6-74ST/WFQ 4-53ST/WFQ 2-32ST/WFQ 0-11ST/WFQ p.bitCoS/Service Classification by Flow Key per port

Ethernet and Legacy Access over DSL for TS2008 Slide OAM Defined per service End-to-End Fault monitoring and performance measurement ITU-T Y.1731 Initiate End-to-end OAM based on IEEE 802.1ag Passive Mode Single segment (link) OAM according to IEEE 802.3ah for remote management and fault indication Customer Premises LA-210CPELA-210 CPE Operator AOperator B 802.3ah (Access Link ME) End-to-End OAM 802.1ag/Y.1731 Phase 2.5

Ethernet and Legacy Access over DSL for TS2008 Slide OAM: 802.3ah-Link Information Auto-discovery, Heartbeat (1/second) Event notification Reporting statistics Variable request & response Querying MIB variables Loopback control Intrusive loopback Organization specific EFM OAM Format Customer Premises LA-210CPELA-210 CPE Operator AOperator B 802.3ah (Access Link ME)

Ethernet and Legacy Access over DSL for TS2008 Slide OAM: 802.1ag-Connectivity 8 OAM levels MEP/MIP/MEG concept Main messages: CC LB LT Service OAM header Service OAM MEPs and MIPs MEP = Maintenance-End-Point MIP = Maintenance-Intermediate-Point MEG = Maintenance Entity Group

Ethernet and Legacy Access over DSL for TS2008 Slide Summary LA Family: DSLAM SHDSL DSLAM LA-110 Site A E1 V.35 Router PBX LAN LA-110/IMA Router PBX LAN ETH 4*SHDSL ATM E1 V.35 ETH Site B LA-210: PSN Core Ethernet, IP, MPLS IPDSLAM Ethernet Ethernet (EFM)Ethernet LA-210 ASMi-54/LRS-102: CP PBX POP SHDSL.bis n x FETH n x E1/T1 E1 SDH/ SONET ETH ASMi-54 LRS-102/MP-4100 IP/MPLS

Thank you for your attention Technical Support

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide ASMi-54 Road Map Phase number ProductMain Description Beta Release Notes Phase 1.0 ASMi-54 with four ETH ports ETH services over 2W, 4W, 8W Status – officially released! Without RADview support Phase 2.0 ASMi-54 with additional E1/T1 port E1/T1 and ETH over 2W,4W,8W Interoperability opposite SHDSL repeaters Q2/08 RADview support Phase 2.5ASMi-54 Daisy chain and multipoint application support TBD Phase 1.0 ASMi-54 card into MP-4100/LRS-102 ASMi-54 card, 16W, with 8E1 and 2ETH ports Q3/08 Phase 1.1 ASMi-54 card with power feeding support Dual slot cardQ4/08 Including remote power feeding support –120vdc

Ethernet and Legacy Access over DSL for TS2008 Slide LA-110 Road Map DateMain FeaturesAccess Network Version 3.5 In Beta PW support SNMP ATM PSN Q4/ Version 4.6 New HW ADSL2+ – E1 – Data port SHDSL (bis) ATM up to 2 pairs 4 Ethernet ports Adaptive clock SHDSL EFM ready ATM PSN

Ethernet and Legacy Access over DSL for TS2008 Slide LA-210 Road Map DateMain FeaturesAccess Network Version 1.0 Testing version Available now SHDSL (bis) EFM up to 4 pairs Ethernet services 4 Ethernet ports PSN Early Q2/08 Version 1.5 (Beta) Ethernet OAM Enhanced QoS SHDSL (bis) ATM up to 2 pairs EVC support (EVPL) HW PW ready PSN ATM Q2/2008 Version 2.5 Beta TDM PW Adaptive clock recovery Standard PM per Y.1731 SNMPv3 PSN ATM Q4/2008 (preliminary) Version 2.6 Based on version 2.5 feature-set NTR VDSL2 bonding (not finalized yet) PSN

Ethernet and Legacy Access over DSL for TS2008 Slide LA-210 Road Map DateMain FeaturesAccess Network Q1/2009 Version 3.0 Beta CLI Per EVC Shaping Hierarchical scheduling ACL with filter, drop, rate limit per IP range, Ethertype, MAC address Limit number of MAC OAM Enhancements: IEEE OAM MIP – pending MEF SOAM Probe pending standardization PSN ATM

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide Ethernet Access over DSL-LA OptionNetwork LinkServices Access Network LA-210/SHDSL SHDSL up to 4 pairs (EFM bonded) One pair of VDSL2 1/4 Ethernet ports *1 E1/T1 port (TDM) *1 serial port (TDM/HDLC) PSN LA-110/SHDSL SHDSL 2/4W 1 E1/T1 port (ATM/TDM) 1 serial port HDLC TDM FR 4 voice ports (VoDSL) *1/4 Ethernet port ATM and PSN LA-110/SHDSL/IMA SHDSL 4 pairs with IMA 1 E1/T1 port (ATM/TDM) 1 serial port HDLC TDM FR 1 Ethernet port ATM and PSN LA-110/ADSL ADSL ADSL2+* 1 E1/T1 port (ATM/TDM) 4 voice ports (VoDSL) *1 serial port TDM FR *1/4 Ethernet port ATM and PSN

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide LA-210 Flow Based Forwarding Model By CoS Step 6 – P. Bit priority marking: Adding the P.bit to the SP-Vlan, according to user configured profiles. Step 2 – Flow Mapping: Defines VLAN members per flow Step 3 – Assigning Fixed CoS per Flow/CoS per P.bit Step 4 – Policer Per CoS: Define the CIR/EIR/ CBS/EBS Bw criteria per CoS Step 5 – Configuring Strict or WFQ priority, according to user configured profiles. Note Priority Queues are fixed to CoS. CoS per Flow Flow 1 = CoS 3 Policer per CoS CoS 3=BW profile 1 Flow 1 (EVC 1) CE-VLAN= 1 Flow 1 (EVC 1) CE-VLAN : 555 p.bit p.bit 4 Policer per CoS CoS 7=BW profile5 Flow 2 Up to 8 flows Policer per CoS CoS 4=BW profile3 Step 1 – Flow Classification Editing Adding SP-VLAN Marking CE-P.bit  SP-P.bit UNINNI CoSQueuesST/WFQ mng5 6-74ST/WFQ 4-53ST/WFQ 2-32ST/WFQ 0-11ST/WFQ p.bitCoS/Service Classification by Flow Key per port

Ethernet and Legacy Access over DSL for TS2008 Slide Mapping User Traffic to Services On user ingress – traffic is mapped to Service by one of the following criteria: P.Bit VLAN ID IP Precedence DSCP C-Priority Bit C-VLAN ID Layer 2 Frame Structure DSCP Layer 3 Frame Structure IP Precedence

Ethernet and Legacy Access over DSL for TS2008 Slide CoS/Services Mapping CoS Mapping criteria: VID’s + P.bit: 10 / 5 15 / 3 CoS/Services P.Bit 6 4 VLAN ID EVC1 EVC2 EVC3 UNI CoS/Services 0 7 EVC2 VID6 EVC1 VID6 VID IP Precedence/DSCP CoS/Services DSCP Layer 3 Frame Structure IP Precedence 3

Ethernet and Legacy Access over DSL for TS2008 Slide Policer Per Service/Flow Bandwidth Control Traffic policing per ingress Service Dual Token Bucket mechanism (CIR+CBS, EIR+EBS) per policer 2 rate (CIR/EIR), 3 color (Green/Yellow/Red) marking: Green:0 to CIR – always ‘respected’ Yellow: between CIR to EIR – Will be respected until the queue reaches a predefine threshold, then it will discarded Red: above EIR – always discarded EVC1 EVC2 EVC3 UNI EVC2 CoS 1 CoS 4 CoS 7

Ethernet and Legacy Access over DSL for TS2008 Slide Queues/Egress Rate Limit/Scheduler MNG Traffic Always get the Highest Queue 4 Queues on the Egress (4th Q has the Highest Priority) Each Queue can be configured as Strict/Weighted Fair Queue (100 Weights) Egress Rate Limit per Queue/Port (DSL) Scheduling: Strict on Top of WFQ WFQ (Weight of Q) ÷ (Weight of all Q) Example:Queue #2  40 ÷ 80 = ½ Queue #1  30 ÷ 80 = 3/8 Queue #0  10 ÷ 80 = 1/8 0 3 Rate Limitation /Shaping Scheduling 4 MNG Strict WFQ=40 WFQ=30 WFQ=10 2 1

Ethernet and Legacy Access over DSL for TS2008 Slide Editing And Marking Editing the SP-VLAN ID towards the network Stack None Marking the Flow Priority on the Egress according to: P.Bit (802.1p) IP Precedence DSCP Editing And Marking Network Editing And Marking VID’s: 10,15,20-30 SP-100 P.Bit 7 Unclassified SP-200 P.Bit 3

Ethernet and Legacy Access over DSL for TS2008 Slide

Ethernet and Legacy Access over DSL for TS2008 Slide Continuity Check (CC) OAM CC OAM Defined per EVC, allows for one-way connectivity monitoring Loss of Continuity (LOC) is declared (only at the sink side) upon 3.5 seconds without receiving CC OAM frame Loss of Continuity (LOC) is cleared upon sink receiving 2 CC OAM frames within a window of 3.5 seconds Upon CC failure Send trap Update active alarm log Update statistics Optional uplink switch-over Customer Premises E-NTUCPEE-NTU CPE Operator AOperator B CC OAM Frames CC SourceCC Sink

Ethernet and Legacy Access over DSL for TS2008 Slide Loopback (LB) OAM Defined per EVC, allows for non-intrusive loopback (round trip) connectivity monitoring Sent from MEP, looped by either MEP or MIP LB Failure is declared upon 2 seconds without receiving the specific LB OAM frame Upon LB failure Send trap Update active alarm log Update statistics Optional uplink switch-over Service OAM MEPs and MIPs Customer Premises E-NTUCPEE-NTU CPE Operator AOperator B LB OAM Request LB OAM Reply

Ethernet and Legacy Access over DSL for TS2008 Slide Diagnostic Loopbacks Layer 1 Loopback – loopbacks traffic from Rx to Tx Out of service – disrupts service Cannot traverse Ethernet bridge Performed on all traffic Loopback activation is via management not OAM protocol Layer 2 Loopback – loopbacks traffic and swaps MAC Addresses Replaces Source Address with Destination Address Can traverse Ethernet bridges Performed per VLAN (or EVC) No Layer L2 Loopback Tester ETX Tester With Layer L2 Loopback

Ethernet and Legacy Access over DSL for TS2008 Slide Link Trace (LT) OAM Once a problem detected with CC or LB than LT can be used to pin point where the problem is OAM is sent to the final MAC address and all nodes in the path that receive the LT request send back LT response, this way the failure point is found Can be used also the resolve disputes when more than 1 network is used Customer Premises E-NTUCPEE-NTUCPE Operator AOperator B LT Req LT Rep