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Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 1 1 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 2 3 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Designing Optical Infrastructures for IP Networks Session OPT-231 4 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Market Trends • Fiber everywhere • Decreasing costs of bandwidth • Optical infrastructure • New services Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 3 5 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. POS MPLS ATM IP I PPP/HDLC / SONET/SDH / Fiber i IP I ATM/FR / SONET/SDH / Fiber i IP I POS SONET/SDH / Fiber i IP I Fiber i DWDM UCP POS 622Mbps DWDM 2.5Gbps POS DWDM Channels 10Gbps POS Mbps x 10Mbps x100Mbps Gbps x10G Architecture Has Been Evolved at Every Two Years to Increase the Capacity by Ten(10) Multiplexing, Protection, and Management at Every Layer Evolution of Internet Backbone Architecture Early 1990s l 1996– 1997– 2001– 1999– PPP Point to Point Protocol POS Packet Over SONET/SDH DWDM Dense Wave Division Multiplexing MPLS Multi -Protocol Label Switching UCP Unified Control Plane IP I POS MPLS Fiber i DWDM 6 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Moving up the Services Value Chain IP Router Fiber Lambdas Wavelength Routing SONET Value Add ServicesValue Add ServicesTDM Services ?Services ?Transit ? Services Managed Bandwidth Optical Technologies L3 Services IP VPN IP QoS Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 4 7 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. • Many EMS layers, and technologies • Service introductions synchronized with each layer • Service topology dependent SONET Rings: Add/Drop Multiplexers, Digital Cross Connects Point-to-Point DWDM ATM Mesh IP Router Mesh Complex Core Network Management 8 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Depreciation 31% G and A 7% Sales and Marketing 13% OAM and P 49% How to Build Better and Cheaper Optical Internet? • OAM and P cost dominates most Service Provider’s budgets Source: ARMIS 43-01 Reports and Probe Research, Inc. Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 5 9 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. IP Routers Requiring Connectivity Service Velocity • Create service velocity: Intelligent network elements, and simplified OSS Distributed network database Circuit-routed, Ethernet-like Inherent scaling Service-driven topology 10 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Optical Technologies Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 6 11 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Service PoP Metro Network Connects Customers to Services Core Network Interconnects PoPs Physical Rings Logically Hub and Spoke Fragmented Market Rapid Change Physical Point-to-Point Logically Peered Established Market Change Emerging (Ring-Mesh) IP+Optical Metro/Core Architecture 12 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Optical Transport Options • Dark fiber • SONET/SDH • DWDM Fiber DWDM SONET/SDH GE IP Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 7 13 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Dark Fiber • Effective alternative if fiber plant capacity is not limited or there is no need for bandwidth multiplication • Modest distance (80 Km or less) • No statistical gain • Considerations when deploying IP infrastructures over dark fiber Fiber plant—capacity and topology Power budgets—optics reach Signal loss (due to attenuation and dispersion)—optics reach Network design must address protection 14 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Effects of Jitter and Noise Jitter Distorts the Signal in the Temporal Domain Noise Distorts the Signal in the Amplitude Domain Error If Signal Is in This Area Signal AmplitudeTime Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 8 15 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Optical Attenuation • Specified in loss per kilometer (dB/km) 0.40 dB/km @ 1310 nm 0.25 dB/km @ 1550 nm • Loss due to absorption by impurities 1400 nm peak due to hydroxyl (OH) ion absorption 0.1 0.2 1.2 1.3 1.4 0.8 1 0.4 0.6 1.5 1.6 1.7 Wavelength, µm Loss, dB/km1310 Window i 1550 Window i 16 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Calculating Link Loss Budget Link Loss Budget = Optical Power Budget— Design Margin— Power Penalties Optical Power Budget 26dB (OC-48c POS [1550nm]) Design Margin (EOL) –1dB Power Penalties –2dB (OC-48c POS [1550nm]) Connector and Splice –3dB Link Loss Budget 20dB Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 9 17 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Link Loss Budget Example Tx Rx Fiber Distribution Panel Fiber Distribution Panel Transmitter Power –2dB Fiber Patch Fiber Patch Receiver Sensitivity –28db 80Km Fiber Span 1dB –3dB 0.25dB/Km + 1dB for Splice Loss –19dB 1dB –20dB At Receiver Link Loss Budget 20dB 18 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. SONET/SDH Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 10 19 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. SONET • Widely deployed optical transport technology • TDM transmission • Optimized for voice traffic • Proactive fault and performance monitoring capability • Fast restoration ? 50 msecs 20 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. SONET/SDH Network Configurations Four Fiber Bi-directional Ring Traffic with Neighboring Pattern, Reusable Bandwidth 4F BLSR Traffic with Neighboring Pattern, Reusable Bandwidth Two Fiber Bi-directional Ring 2F BLSR RCV TX Unidirectional Path Switched Ring All Traffic Homing to a Central Location UPSR Linear Up to 16 Nodes, ADM Point-to-Point Two Nodes, Terminal Mode Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 11 21 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Packet Over SONET (POS) 22 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Working Router Working Router Working Router Protect Router W W P P Protect Group Protocol POS APS/MSP • APS—Automatic Protection Switching (APS) • SDH—Multiplex Switching Protection (MSP) • Uses K1 and K2 byte; 1 + 1 Protection SONET/SDH Network Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 12 23 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Dark Fiber Section + Line OH ti i Path OH t Concatenated Payload Flag 8 l Address 8 Control 8 t l PPP Packett FCS 16/32 / Flag 8 l WDM ~~~ ~~~ POS EDGE Core EDGE POS Applications • PoS Packet-over-SONET/SDH • Runs over dark fiber, SONET, or WDM • Enables transport “mix and match” • Provides efficient evolution path for incumbents • Provides optimized transport for greenfield builds • Standards based TDM ADM ADM ADM ADM 24 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Dynamic Packet Transport DPT Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 13 25 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. SRP-Based LAN/MAN Section + Line Overhead ti i Path Over- head t - … MAC IP Packet I t MAC IP Packet I t Concatenated Payload t t l DPT Overview • New Layer 2 MAC protocol • Uses SONET/SDH framing • Bandwidth efficient • Fairness (SRP-fa) • Scalable • Fast protection switching and service restoration • Multicasting and priority 26 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. DPT Ring Dynamic Packet Transport • Maximize bandwidth efficiency • Bandwidth consumed only on traversed segment • Multiple nodes transmit concurrently • Fairness via SRP-fa • Self-healing through IPS • Minimize provisioning and configuration Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 14 27 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Dense Wave Division Multiplexing DWDM 28 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. DWDM • Used to provide bandwidth multiplication where fiber plant capacity is scarce • No protection on tributary side • Network design must address protection Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 15 29 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. 40km 40km 40km 40km 40km 40km 40km 40km 40km 120 km 120 km 120 km DWDM Transmission—10 Gb/s 4 fibers 1 fiber 32 regenerators 4 optical amplifiers DWDM Offers Compelling Economics DWDM for Fiber Gain OA OA OA OA OC-48 - OC-48 - OC-48 - OC-48 - OC-48 - OC-48 - OC-48 - OC-48 - TERM 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR TERM TERM 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR TERM TERM 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR TERM TERM 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR 1310 RPTR TERM 30 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Optical Networks Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 16 31 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Design Considerations (Backbone) • Infrastructure redundancy Routers Links No single point of failure • Path redundancy Load sharing Protection • Capacity planning and traffic engineering • Topology 32 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Clocking and Synchronization SONET/SDH Network PRC ADM Linecard Rx Tx Rx ADM Linecard Tx Tx Rx Rx Loop Timed Loop Timed Internal Clock Linecard Linecard Rx Tx Tx Rx Loop Timed Switch Fabric Linecard Linecard Tx Tx Rx Rx • Set clock source internal for back to back connections, dark fiber and DWDM • SDH ADM or term—clocking derives from the Stratum 1 source in the SDH network • Applies to both POS and SRP • Clock the router from Line Always! Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 17 33 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Regen Regen OC-48 POS/SRP (LR) OC-48 POS/SRP (LR) 80 Km 80 Km 80 Km Extending the Distance • Use regenerator 3R—Re-amp, Re-shape and Re-time • Can be used for both POS and SRP • Cisco regen supports IP over DCC for management • 30 regens can be cascaded to get a distance of 2400 Km (? 1500 miles) 34 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Fiber Plant DWDM SONET/ SDH Router Optical Network Infrastructure Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 18 35 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Topology Options (Backbone) • Mesh Full or partial • Point-to-point POS • Ring POS or SRP 36 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. POPB POPD POPC Full Mesh POPA Primary path Secondary/Load Share path Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 19 37 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Full Mesh • All the backbone routers are connected to each other • Single hop from any backbone router to the other • Depending on the number of routers in the backbone, may require a lot of slots/ports n(n-1)/2 ports 38 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. POPB POPD POPC POPA Primary path Secondary/Load Share path Partial Mesh (1) Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 20 39 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Partial Mesh • Each backbone router is connected to two or more backbone routers • Multi-hop to some backbone router • Uses less slot/port and fiber compared to full mesh topology • Cost effective 40 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Point to Point—POS • Point to point connection using POS OC-3/STM-1—OC-192/STM-64c • Encapsulation—HDLC/PPP • Connecting to SONET/SDH APS/MSP for protection • Connecting to DWDM or Dark fiber Multiple links for load sharing and protection Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 21 41 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. POPB POPC POPA Primary path Secondary/Load Share path DWDM POPD Connecting to DWDM 42 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. POPB POPD POPC POPA Working Protect W P W P W P W P SONET/SDH Connecting to SONET/SDH Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 22 43 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. DPT PoP Design OC-48/STM -16c Internet Backbone OC-192/STM-64c POS Internet Backbone OC-192/STM-64c POS 44 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. MPLS Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 23 45 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Route Chosen by IP Routing Protocol Route Specified by Traffic Engineering Traffic Engineering with MPLS • Why traffic engineer? Optimize link utilization Specific paths by customer or class Balance traffic load • Traffic follows pre-specified path • Path differs from normally routed path • Controls packet flows across a L2 or L3 network infrastructure 46 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Unified (Optical) Control Plane Overview Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 24 47 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Network Element Standard Body Routing Signaling Available Optical Cross Connect Optical Cross Connect MPLS IP-LSR None ATM Forum IETF Proprietary PNNI Constraint Based Proprietary PNNI LDP/ RSVP Future Deployed Deployed Existing Control Planes • Separate control planes exist for L1/2/3 • Limited communication creates isolation • Results in an overlay network model Source: John Drake—MPLS Conference 1999 48 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. UCP Protocols Standards Summary Drafts as of January 2001 Function MP ? S/GMPLS O-UNI G.ASON Routing Protocol Signaling Link Management, Verification, Neighbor Discovery, Etc. IGP TE Extensions RSVP/CR-LDP Extensions LMP N/A Model Standards Body Peer/Overlay Peer/IETF LMP Overlay to Peer OIF RSVP/CR-LDP Extensions N/A Central Control, IP/ATM/ SONET Clients Overlay ITU-T Out-of-band Client UNI Peer Overlay Overlay Is a Subset of the Peer Model Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 25 49 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Services Network and Service Management Unified Control Plane Internetworking Operating SystemPacket Labels/VPI VCI Packets/Cells Wavelength Routing DWDM Transport SONET/SDH ??Labels Unified Control Plane 50 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Control Plane Functions • Resource discovery • Connection management Path set-up/tear down Maintenance and monitoring • Topology/state dissemination Reliable broadcast/Flooding • Path Selection Constraint-based routing Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 26 51 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. OCP/UCP Technology Scenarios • UNI Used to build point-to-point ‘SVC-Like’ circuit set-up mechanism Used to accelerate service delivery of IP or other service definitions across an optical overlay network topology • GMPLS Used to enable standard protocol based circuit provisioning and restoration technique node by node within the interior of an optical transport network Used to construct a multi-vendor optical transport network Enables scalable node to node peering and full-mesh topologies Allows for the administrative boundary of a UNI Leverages existing IP network layer service definitions • Miscellaneous others Pure IP Control Plane, Central Server Provisioning, GSMP (VSI) 52 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Optical Network Cloud OC-48/STM16c OC-192/STM64c UCP UCP Layer 3: Packet Core Unified Control Plane Benefits: • Network simplification: common framework for packets and wavelengths • Reduced provisioning costs • Increased service velocity • Fast path restoration Evolution of Optical Core (IP over ? ) with Unified Control Plane Layer 1: Optical Core Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 27 53 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Customers POP Intraconnect Customer Ingress Egress OLSPs Egress Transit Router + OXC: Optical Pass-through for IP Traffic • Transit Traffic forwarded thru OXCs Offloads core routers of per-packet transit processing Frees up IP router resources for handling customer traffic • One-hop O-LSPs across core network No intermediate per-packet processing lower latency and jitter Improved Network Performance 54 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Deploying IP Services Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 28 55 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Voice Video WWW TV E-Mail SNA What’s the Problem? • API to API service creation • Requirement for mobility • Full IP network services 56 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. FDDI Internet FDDI FDDI Web Farm Web Farm Web Farm Many Flows Duration Push Server Complexity’s an Issue Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 29 57 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. IP Services: Essentials • Open standards • Scalability • Reliability • Manageability • Low latency • Network services DNS, DHCP, hosting, caching, AAA, number translation, SCP, firewall, NAT, etc… • IP QoS • IP traffic Eng • IP VPN • IP any-2-any • IP multicast • IP security 58 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Services: The Challenge • The optical IP network needs to meet the requirements of the applications • Different services have different requirements: Voice, videoconferencing, distance learning-low latency, low jitter Bulk data transfer-high bandwidth Email-no demanding requirements Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 30 59 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Services: The Challenge • To ensure service quality, each application or flow, needs to be differentiated from one another • Non time critical applications, e.g. www, could impact time sensitive applications, such as voice or video 60 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. © 20 , Cisco Systems, Inc. 3005 1165 0 The Need for QoS in IP Networks Consider Voice… Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 31 61 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Traditional Voice Networks Cross Connect Class 5 Switch Class 4 Switch Class 4 Switch Class 5 Switch Cross Connect ADM ADM ADM ADM ADM ADM ADM ADM ADM SONET/SDH Rings and or ATM Network Provides Low Delay, Low Jitter, and Protection, (BLSR/MSP Ring) ADM ADM ADM ADM ADM ADM ADM ADM ADM 62 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Unacceptable Utility Business Toll PCM Quality Bandwidth (kbps)8 16 24 32 40 48 56 64 0 ADPCM 32 (G.723) LD CELP 16 (G.728) LDCELP 16 (G.728) ADPCM 16 (G.726) LPC 4.8 MPMLQ (G.723.1) Voice Quality: Compression Standards CS-ACELP 8 (G.729) Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 32 63 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Why Is It So Important to Minimise Delay? Usability of Voice Circuit As a Function of End-to-end Delay 0 0.5 1 100200300400500600700800Time (msec) UtilityCB Radio Fax Relay, Fax Broadcast Toll Quality Satellite I-Phone Today 180 ms End to End • To Hit the Target: Eliminate PC delay Lower network latency Tighten network jitter li i t l t lt i t t jitt 64 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Delay Considerations in IP Networks Codec Packetization Output Queuing Access (Up) Link Transmission Backbone Network Transmission Access (Down) Link Transmission Input Queuing Jitter Buffer Codec Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 33 65 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Encoder/decoder Delay (Algorithmic Plus Processing and VAD) 30 ms Waiting and Framing (10 ms Frames) 10 ms Move to Output Queue Negligible Wait in Queue (Depends on Queuing 0–8 ms and Congestion) Access up Link -Backbone-down Link Variable (1 ms Per 100 Miles) Move From Input Queue to DSP Negligible Jitter Buffer 4 Ms–40 ms Coder Process Delay Total: (Excluding up Link, Backbone, and Down Link) 45 ms Calculating a Delay Budget (G.729) 66 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. What Is Referred to as QoS? • The following parameters are usually equated with QoS: Bandwidth guarantees Admission control Delay Jitter Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 34 67 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. QoS with IP Class of Service • Implemented at network Layer 3 • Media independent • Efficient use of available bandwidth through statistical multiplex • Bandwidth guarantees, delay, and jitter limits via advanced queuing mechanisms • Admission control only for applications that need certain guarantees (gatekeeper) • Connectionless—no TDM 68 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Changing QoS Requirements • Changing applications change requirements • Classic voice requires dedicated 64k channel in TDM network • Voice over IP designed to work on IP transport networks, can tolerate delay and jitter within limits • IP transport is inherently statistically multiplexed, but can limit delay and jitter to suit VoIP applications Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 35 69 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. VoIP in the Intranet today… PSTN QoS IP Optical Core Edge Branch Office PBX Larger Branch Office Headquarters PBX I-Phone H.323 S/W Residential POS WWW VOD Content 70 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. VoIP Futures…. Headquarters PBX I-Phone H.323 S/W Optical Network Cloud UCP UCPPBX Branch Larger Office Residential WWW VOD Content PSTN Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 36 71 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Network Wide IP QoS • Packets are marked at the ingress or by the application and carry their classification throughout the network • Core devices use this information to provide required services • Easier to manage 72 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Congestion Issues • Routers by design can have congested links when an interface is offered more load than it can support for an extended period of time • This can cause three things: Packet loss due to output queue overflow—some traffic might be sensitive to it Added and varying delay-real time applications impacted Bandwidth for some important data is insufficient Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 37 73 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Dealing with IP Congestion • Impact can be minimized the following way: Drop less important traffic before high priority traffic Handle delay sensitive traffic different than bulk data Ensure bandwidth for specific traffic is managed 74 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Edge Functions • Packet classification Precedence setting with CAR • Bandwidth management Rate limiting with CAR Traffic shaping • L3 metering NetFlow data export Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 38 75 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Backbone Functions • High-speed switching and transport Distributed switching (CEF) • QoS enforcement Congestion avoidance (WRED) Congestion management (MDRR) • QoS interworking IP-ATM QoS interworking (VC per CoS) 76 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. L3 CAR Apply Ingress Rate Thresholds Determine Packet Class Administer Packet Class Apply Egress Rate Thresholds Traffic Metering WRED/MDRR Premium Medium Standard Summary of Network IP QoS Packet Classifier t l ifi L3 CAR Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 39 77 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Summary • We have seen that it is very feasible with careful design to deliver differentiated IP services over an optical infrastructure • Different service requirements; (Delay, Jitter Etc.) can be accommodated using the tools available, CAR,WRED,MDRR • Different traffic flows can be effectively marked, and differentiated from each other, enabling, Service providers to Offer billable, robust, IP services to their customers • In the future the unified control plane will allow for service velocity 78 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Questions ? Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 40 79 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Designing Optical Infrastructures for IP Networks Session OPT-231 80 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved. Please Complete Your Evaluation Form Session OPT-231 Copyright © 1998, Cisco Systems, Inc. All rights reserved. Printed in USA. Presentation_ID.scr 41 81 OPT-231 2948_05_2001_c1 © 2001, Cisco Systems, Inc. All rights reserved.
