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1、,ALL OPTICAL IP NETWORKS,Myth or reality?,Luc Ceuppens,Vice President, Product MarketingInfrastructure Product Group,2,Copyright 2010 Juniper Networks, Inc.,,OUTLINEOptical bypass: what, why and how?The forgotten piggyChallengesMyths and realitiesConclusion and summary,3,Copyright 2010 Juniper Netwo
2、rks, Inc.,,OPTICAL BYPASS: AN INTRODUCTIONNetwork planning technology where optical connectivity istopologically richer than IP/MPLS node map. IP/MPLSnodes are by-passed by Select wavelengths inside the transport optical element (optical bypass) OTN circuits (opaque bypass, OTN bypass)Often populari
3、zed as a tool to reduce network CAPEX andenergy footprint Reduction of transit traffic (and hence ports) on IP/MPLS node On shorter segments (less than 1,500km) a “bypass” wavelength can beoptically amplified in the node without OEO conversion, further reducingthe costIn essence, the promise is that
4、 bypass shifts the CAPEXbudget out of IP/MPLS equipment towards optical gear.,4,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: GOOD IDEA?OB is backed up with significant amount of research data andwhitepapers. Several peer-reviewed CAPEX network modelstudies were done to prove OB monetary/en
5、ergy savings.List of popular titles include“Evolution of WDM Optical IP: Cost and Energy” (R. Tucker)“Packet Layer Topologies of Cost Optimized Transport” (NSN)Deliverables within European “IST Nobel 2” project and othersSeveral service providers (SwissCom, DT, FT) have endorsedoptical bypass in pre
6、sentations and articles in optical-themedmagazines. OB also enjoys significant analyst coverage.Note 1: OB is sometimes referred to as “optical circuit switching” OCS, or “optical cross-connect” OXC)Note 2: This presentation uses several graphics from above mentioned papers,5,Copyright 2010 Juniper
7、Networks, Inc.,,COMPONENTS OF OPTICAL BYPASS1. WDM/ROADM shelves (in red) serving IP/MPLS nodes2. Selective wavelength routing in the optical layer,6,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: ONLY THE BEGINNING?Transition from all-electrical switching (“opaque”) in everynode to OB/OCS (
8、“transparent”) is often viewed as precursorto all-optical packet processing:In this “Stage 1”, OCS elements are often shown operatingunder G-MPLS control for dynamic path provisioning,7,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: ELEVATOR PITCH1. IP/MPLS port cost (in abstract units)2. OX
9、C/ROADM port cost (in abstract units)Replace PACKET switching by OPTICAL switching = LOWER COST!,8,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: ELEVATOR PITCH (CONTD)Did anyone notice a pink piggy?If not, lets try again,9,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: THE FORGOTTEN
10、 PIGGYThere is a “pink piggy” in the network costpicture, so large that people barely notice it.It is the same piggy that drove thetransformation from circuit to packet as well asIP convergence.This piggy is called “cost of bandwidth”.It feeds upon available bandwidth and returnsmonetary services. I
11、t heavily favors statisticalmultiplexing over circuit switching because it caneat much less and monetize much more.So, why do some people ignore it?,10,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: CHALLENGESThe smallest unit in OCS is a “wavelength”.Optical Bypass is contradictory to servi
12、ce providers desire toimprove spectral efficiency. The higher the wavelength speed, the less opportunityfor bypass Literature actually acknowledges thisTraffic matrices tell a different story than bandwidth matricesDynamic provisioning of a light path thru a network of opticalswitches (e.g. “packet
13、over light LSP”) requires complexpower/amplification computations for OXC nodes and cantake several minutes,11,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: MYTH 1IP/MPLS NODES IN THE CORE ARE ROUTING PACKETSThe packet route is already known at the core ingress point.However, packet core sw
14、itches are NOT doing routing theyare intelligent statistical multiplexors filling the core bandwidthat packet-level resolution. Opportunity to replace core routers by lower cost LSRs,,Edge12,Core,Core,Inner CoreCopyright 2010 Juniper Networks, Inc.,OPTICAL BYPASS: MYTH 1IP/MPLS NODES IN THE CORE ARE
15、 ROUTING PACKETSPacket network evolutionOtherNetworksOtherNetworks,13,Copyright 2010 Juniper Networks, Inc.,,OPTICAL BYPASS: MYTH 2TRANSIT TRAFFIC CAN BE EFFICIENTLY “REMOVED”,14,,OPTICAL BYPASS: MYTH 2TRANSIT TRAFFIC CAN BE EFFICIENTLY “REMOVED”Traffic in real networks follows complex distribution patternsand static de-multiplexing wastes bandwidthTraffic BC,
