Presentation on theme: "Network Operator Perspective MPLS: 12 Years After Tom Bechly"— Presentation transcript:
1Network Operator Perspective MPLS: 12 Years After Tom Bechly IETF 74, San Francisco IAB Plenary March 18, 2009
2MPLS: A Successful Protocol MPLS has been and is a successful protocolFrom perspective of RFC 5218 (What Makes for a Successful Protocol?), MPLS was used for its intended purpose and at intended scaleGoal was to switch packets to support rapidly expanding global networksMPLS is “wildly successful” (RFC 5218) in that its use has exceeded its original design goal thru development of numerous extensionsFrom service provider perspective MPLS was successful in supporting growth, reducing cost, and providing basis for new servicesOriginal goal of bringing Layer 2 switching speed to Layer 3 was accomplished, but somewhat discounted over time due to hardware evolutionL2 was hardware switched and L3 was process switchedMPLS was easily leveraged for traffic engineering, VPNs, and layer 2 transport.For the service provider, MPLS has become one the most reached for and extended tools in the tool chest (150+ RFCs)
3MPLSCustomer Edge (CE) RouterProvider Edge (PE) Router/SwitchProvider Core Router/SwitchMPLS CORECE RouterPE RouterP RouterEnables network edge routers to apply simple MPLS labels to packets or framesForwards packets by swapping labels with minimal lookupIntegrates Layer 2 switching and Layer 3 routingThis diagram introduces how MPLS manages network traffic.MPLS is a high-performance method of forwarding packets (frames) through a network. It enables routers at the edge of a network to apply simple labels to packets (frames). ATM switches or existing routers in the network core can switch packets according to the labels with minimal lookup.MPLS integrates the performance and traffic management capabilities of Data Link Layer 2 (frame relay and ATM) with the scalability and flexibility of Network Layer 3 (IP) routing.MPLS offers additional benefits when applied to ATM networks. MPLS integrates IP routing with ATM switching to offer scalable IP-over-ATM networks.
4MPLS/RSVP-TE Benefits MPLS with RSVP-TE provides overall path control in networkUse with constraint based routingControl over latency and delay variationBridges gap between ability to deploy capacity versus current demand in existing networkUse of MPLS allowed gathering measurement statistics on LSPsProbably more important than actual path controlProvides ability to accurately measure traffic between router pairsTraffic volumes, latency, and delay variationMeasure traffic between hubs, metros, and regionsMeasure asymmetry of flows, over timeA time series depiction can be built to trend traffic for efficient investment and to provide required serviceMPLS became an enabler for the development of additional servicesL2 VPNs and L3 VPNs
5Verizon Public IPAS 701 was initially implemented as an overlay over a dedicated frame relay networkPath control was effected thru manipulating path of frame relay PVCsAs capacity requirements increased, the network was migrated to an overlay over ATMThe cost of this became untenable, as capacity requirements continued to increaseMPLS with RSVP-TE deployed in EMEA (AS 702) in 1999First deployment of RSVP-TE in production networkDeployed in US (AS 701) in 2000Deployed for traffic engineering to provide control over path selection that was not available thru L3 protocolsShortest path algorithm did not always provide optimal routeMPLS technology has enabled the Verizon Public IP network to grow to be one of the largest in the world
6Verizon IP Network 410 unique switch/router hubs (PoPs) Our global IP network spans more than 446,000 miles across 150 countries on six continents and is backed by experienced sales and service reps around the globe.Verizon continues to invest in our facilities-based strategy to deliver the performance and reach to meet our customer’s needs from Small Business to Enterprise to Government to our Wholesale market segments of ISPs and leading content providers.410 unique switch/router hubs (PoPs)Six continents, 150+ countries
7Verizon Layer3 VPN Services: VBNS+ and Private IP vBNS (very-high-performance Backbone Network Service) was established in 1995Cooperative research and development agreement between Verizon (formerly MCI) and National Science Foundation (follow on to NSFnet)Evolved to a commercial product: vBNS+ for gov and edu marketMPLS routing/switching implemented in network in 1999Initially MPLS was implemented for traffic engineeringL3VPN (RFC 2547) was implemented in 2001There are approximately 40 nodes in 19 US cities, full mesh of TE LSPsVerizon PIP (Private IP) was established in 1999Layer 3 VPN (RFC 4364), wide area network for business customersQuality of Service, strong SLAs, etc.Large global networkThere are approximately 625 nodes across 162 cities in 59 countriesUses LDP for label distribution, with partial mesh of LSPsDesigned and supported by Verizon’s next generation engineering organization, it has been in existence for more than ten years; MPLS has been a principle switching technology within the vBNS+ platform for the past five years. The vBNS+ has a proven and history of extraordinary performance for numerous government clients who rely upon the network for vital/critical applications.Verizon recognizes that when customers entrust their critical operations to a network service, they are quite literally putting their ability to operate in the hands of the network provider.We take this responsibility seriously and are proud to report that during its nine years in operation, the vBNS+ network has provided an exceptionally high level of availability to customers large and small.” This is despite the evolution, expansion and upgrade of the entire service platform and all its elements, including the replacement and/or upgrade of every switch, router, and trunk which makes up the network. For example, in 1999, Verizon (formerly MCI) completed the transition from ATM to MPLS as the core switching service in the network without adversely impacting our customers’ service.In addition to the technical evolution of the physical components of the network, Verizon has continually led the way in delivering new and advanced services to our vBNS+ customers. In all cases, the advanced networking features and high performance of the vBNS+ network allow clients to enable new applications and next generation capabilities that go beyond traditional wide area networking.
8Private IP Global Reach This is the complete list of countries where Private IP is currently available.vBNS+ International coverage is supported by provisioning on Private IP routers with 6 gateways deployed back in the US.MP10163v5.03
9Verizon Layer 2 Services: MAE® Services and Converged Packet Architecture (CPA) MAE® Services established 1992 as metro Internet Exchange pointEvolved into MPLS based national service for extended peering and L2 VPNs (VPWS), implemented in 2002Service interworking (ATM, Frame Relay, and Ethernet), based on draft Martini pseudowires and draft Shah ARP MediationImplemented across public internet within full mesh of GRE tunnelsISIS, RSVP-TE signaled LSPs, and LDP signaled pseudowiresCPA supports Ethernet access and Ethernet servicesL2 VPNs: both EVPL (PWE3) and VPLS (RFC 4762)Quality of Service, strong SLAs, etc.Large global networkThere are approximately 115 nodes across 27 countriesRSVP-TE used to signal LSPsFull mesh for EVPL and VPLSCurrently 10,000+ LSPs
10Lessons LearnedImplementation defects significantly impact early perception of technologyFor AS 701, there was internal resistance to moving from ATM underlay network to MPLSWhen defects in the MPLS implementation on vendor equipment were encountered these initially viewed by some as defects in the technology
11Lessons not Learned (VPLS) RFC 4762: Virtual Private LAN Service (VPLS) Using Label Distribution Protocol (LDP) SignalingHierarchy is managed thru HVPLS, specified within RFCRFC 4761: Virtual Private LAN Service (VPLS) Using BGP for Auto-Discovery and SignalingHierarchy is managed thru route reflectors and multi-segment pseudowiresBoth approaches are currently in production in different service provider networksSome vendors have implemented both standardsThis increases to overall cost and complexity of technology and network development across the communityResolution and mitigation of differences is far more economic during protocol development than once into implementationGateway function has high development and operational costThe added costs and complexity are continuously accretive
12Lessons not Learned (RFC5085 – PW VCCV) Pseudowire Virtual Circuit Connectivity Verification (VCCV) – RFC 5085Three modes of operation: (Type 1: PWE3 Control Word Bit, Type 2: MPLS Router Alert Label, Type 3: MPLS PW Label with TTL == 1Mode is negotiated, so all three are optionalVendors, to this point, have not implemented all modes nor the same modesThis leads to interoperability issues in mixed vendor networksDelays significantly availability of featureAdds to development and integration costsVCCV ModeVendors YVendors XControl Word*YesNoRouter Alert LabelTTL Expiry*
13Continuing Challenges Latency sensitive customersThese are typically financial customers that are sensitive to a 2ms increase or change in latencyRequire traffic to be on path with deterministic low latencyDue to network event traffic may be rerouted, via Fast Reroute and the re-signaled LSPPaths are recalculated periodically to ensure low latency pathOnce optimal path is available, traffic is re-routed (make before break) to this pathAs this path could be significantly shorter (2 – 10ms), there will be out of order packets that may impact some hostsNodes in network within the core, may carry a high number of LSPsLatency sensitive customers are requesting notification on any maintenance that will impact LSPs carrying their traffic
14MPLS Going Forward MPLS has been an extremely successful protocol It has been widely deployed and extendedMPLS based networks and facilities to continue to grow and expandThis growth is continuing and will continue for some time