Transcript Document
MPLS Deployment Examining the Network Evolution Agenda Overview of the existing network infrastructure. Potential MPLS Networks Current Design Practices and Market Forces Requirements Met by Current Designs Constraints of Current Design Requirements of MPLS for the New Public Network. MPLS Technology Evolution Obstacles to Deployment Benefits of the New Network The Migration Process. The Current Layered Model Moving to an End-to-end MPLS Network The New Services Enabled by an MPLS Infrastructure. Advantages of MPLS Networking New Services Enabled By MPLS Hybrid Switches Created by MPLS Conclusions Overview of the Existing Network Design Potential MPLS Networks Current Design Practices and Market Forces Requirements Met by Current Designs Product Functionality by Product Constraints of Current Design Potential MPLS Networks Target Networks: IP Service Providers of all types, not just ISPs. ISP backbone to start (IP centric). CLEC, ILEC – transport providers take on IP knowledge. Challenges Facing IP Service Providers. Exponential Internet growth (BW, IP prefixes). Need to offer multiple service levels. Need to offer new IP services. Ex.: Virtual Private Networks. Current Design: The Layered Model Content Pop Access Router Switch Access Router Switch Switch Access Core Router Tier 1 Major Carriers Access Router Switch Switch Content Access Router Core Router Access Router Access Access Router Current Practice and Market Forces Today: Layered Model. ATM backbone surrounded by big “Core” IP routers. IP over ATM. Market Forces: IP becomes universal service interface. VPNs, Voice, data (Internet, intranet, extranet), IP multicast. Traditional router vendors trying to push inward to displace ATM backbone. Optical Internetworking poised to grab the very core of the network hierarchy. Requirements Met by Current Designs ATM switching has an enormous presence in the backbone of many service providers: Value-add lock-ins, enabled by connection oriented link layer: Multiple tiers Bandwidth Capacity Congestion Aware Routing Traffic Engineering QoS Traffic Management Circuit (service) Provisioning at ATM Layer These have been developed in the ATM control plane Extensions: UNI PNNI ABR/CBR/VBR/UBR/GFR Different Products Perform Critical Functions POP IP Routers: Classify Traffic Forward IP POP CR CR POP CR CR POP POP CR CR POP ATM Switches Provide Raw Switching Capacity Provides connection-oriented link layer, that enables: Traffic Engineering CR Hard QoS POP Traffic management Constraint-Based / Congestion- AR AR AR AR AR aware routing Constraints of Existing Designs COLL benefits end at router boundary. SPs dislike multiple control plane protocols: ATM and IP Previously Required Because IP Lacked a COLL. No TE, TM, CR or QoS Induces ‘Cost’ Infrastructure Cost Operational Cost Management Cost Perceived Complexity of ATM. The benefits of ATM come at the expense of the “cell tax”. Cells make sense in many portions of the network Cells will move to edge at OC-3 and down DSL, ATM IADs MPLS will still provide control plane Requirements of MPLS for the New Public Network Connection Oriented Networking Comparisons of COLLs The Evolution of IP Products Software and Protocol Requirements Hardware Requirements Network Management Requirements The Requirement: Connections Marketing Debates Not IP vs. ATM Not MPLS vs. ATM Technical Reality: Connection-oriented vs. connectionless ATM IP enabled by MPLS Connection oriented traffic allows for traffic engineering and bandwidth guarantees (QoS) - and is already provided today in technologies like ATM and Frame Relay. IP alone is a connectionless protocol. Its forwarding decision are made on a hop by hop basis. The pinned-up connection is relatively permanent, thereby allowing for resources to be reserved and allocated. MPLS enables to COLL behavior. Traffic Engineering, QoS and Congestion Aware Routing Service Providers with an existing COLL will require MPLS to be a functional replacement. MPLS and ATM as COLLs The charts below reflect that MPLS is providing the key components of a COLL technology. Connection ID Connection Method Explicit Routing Path Setup ATM MPLS VP / VC (2) Virtual Circuits Designated Transit List UNI Signaling Stacked Labels (many) Label Switched Paths (LSPs) Explicit Route Objects CR-LDP or RSVP-TE To meet QoS requirements, even non-ATM LSRs should provide capabilities similar to ATM switches: ATM MPLS Queuing Traffic Scheduling QoS Routing Per-VC queuing Per-LSP queuing Weighted per-VC Weighted per-LSP scheduling scheduling PNNI routing Enhanced IGP (OSPF and IS-IS) Product Software and Protocol Requirements Routing Not the ones you have today. Need TE and QoS Extensions: Maximum Link Bandwidth Maximum Allocation Multiplier (a percentage can be used for oversubscription) Current Bandwidth Reservation Resource class (color, administrative group) Packet loss ratio Link Propagation Delay And several others Signaling Not just LDP or RSVP Need CR-LDP or RSVP-TE With matching properties to above items. Both will survive ! Additional Required Connection Features Combined, they enable the following functions: Crankback Make-before-break Prioritized reroutes Prioritized call setup Bulldozer bits Path computation algorithms MPLS based recovery (recent draft submitted) Sophisticated path computation methods CAC Key Measurements: Calls per second; circuit rerouting; protocol convergence, in the presence of CR CA information. Product Hardware Requirements Classification and forwarding On a per connection basis Queue Schedule Buffer Shape Policing Marking Throttling New methods Class Based Queuing (CBQ) Random Early Discard (RED/wRED) Not per box or per port, but per connection. MPLS: The Common Ground ATM Switches Traditional Routing Connection oriented Networking Connectionless Packet Routing Connection Switching IP Routing and forwarding MPLS Connections for IP MPLS IP ATM already has the right experience with the necessary algorithms. Connection types: Is your MPLS vendor delivering 1994 technology? ATM Network Management Requirements Management is critical component to the migration. Provisioning, billing and accounting is a major operational issue. Sophisticated tools already exist for current networking technologies. Relatively long evolution to meet SP needs. Many SPs have extended these even further through own engineering. These networks can’t migrate and restart the clock, and wait for new tools. They must be available day-1 The Migration Process The Current Layered Model Moving to an End-to-end MPLS Network The Migration Process Easy migration IP/ATM/cells ATM Cells Today IP/ATM/FNNI HW IP/MPLS/FNNI SW IP/MPLS/POS SW F-NNI Technology Encapsulation and MTU ATM Cells Routing Protocol Each step is a fully functional network. ATM AAL5 Header What is not shown F-NNI AAL5 Header Dynamic MTU up to 16k P-NNI POS PPP Header Dynamic MTU up to 16k OSPF, RIP, is that you lose your COLL….which is why you need to add MPLS back on top. Fixed 53 byte MTU P-NNI IS-IS, BGP The New Services Enabled by an MPLS Infrastructure Advantages of MPLS Networking New Services Enabled By MPLS Hybrid Switches Created by MPLS Conclusions Advantages of MPLS network Transport technology independent End to end connections COLL in single control plane POP TE TM QoS CR Greater tunnel hierarchy N2 adjacencies gone Minimizes IP lookup process Intelligence at edge Core can be simpler switches POP POP CR CR CR CR POP POP CR CR CR POP AR AR AR AR AR POP Service Offerings Enabled By MPLS IP Routing/Forwarding on ALL ports. Filtering, policies, firewalling Customer prem. gear MPLS based VPNs (IP VPNs) Virtual leased line MPLS based QoS Service level agreements Voice over IP/MPLS Architectures IP Multicast A New Breed of Switching Product Hybrids that offer Ships In the Night mode (MPLS and ATM) Many carriers today have multiple networks Frame, IP, ATM Replicated operational costs SIN – expose multiple service interfaces to customer over a single infrastructure Only ATM switches can operate in SIN mode VC, VP, POS, MPLS, Frame Relay… Packet-based routers can not Packet based IP centric services only – likely POS/MPLS BUT, if there are other services….… ATM service VC/VP/ L2VPN TDM/CEM This approach is also a low risk approach to building out your next backbone. ATM COLL is proven technology Easily migration to MPLS on same product Move entirely to MPLS when ready Or, stay in SIN mode for hybrid network 4 Modes of Hybrid Operation Edge Con ID Edge 4 modes: hop by hop; ATM; MPLS, SIN Payload Hybrids Redefine Multi-Service Multi service past: Voice Video Data Multi service now POS, ATM, FNNI, IP interface to customer Option of MPLS on top of all Hybrid acts as adaptation layer Connection oriented Voice video data service, enable multi-application uses: The Effect of Hybrid Switches in the Network Design POP Full mesh of SPVCs between all Core Routers POP CR Many diverse paths exploited through ATM core CR POP Routers’ View of the Network CR CR POP POP CR CR POP ATM Switch CR POP AR AR AR AR AR CR Core IP Router AR Access Router / AS Border Router Conclusions MPLS promises to be a powerful Marring the best of IP and ATM It will take time to meet all high Functional replacement Network management unification technology expectation. MPLS is not vanilla IP. SPs will be very cautious, and will be sure they know what they are getting when vendors talk about MPLS. SPs do require a low risk, simple migration process. Can not build out a parallel network MPLS is just a technology, with great potential Must enable new services (revenue) Reduce operational burdens (costs) Hybrid Switches enable a low risk migration process, while enabling a truly multi-service network. Thank You!