MPLS DeploymentExamining 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 DesignPotential MPLS Networks

Current Design Practices and Market ForcesRequirements Met by Current Designs

Product Functionality by ProductConstraints 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

T ier 1M ajor C arrie rs

PopContent

Access

Access

ContentCore Router

Core Router

Access Router

Access Router

Access Router

Access Router

Access Router

Access Router

Switch

SwitchSwitchSwitch

SwitchSwitch

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: Multiple tiers

Bandwidth Capacity

Value-add lock-ins, enabled by connection oriented link layer: 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

IP Routers: Classify Traffic Forward IP

ATM Switches Provide Raw Switching Capacity Provides connection-oriented link

layer, that enables: Traffic Engineering Hard QoS Traffic management Constraint-Based / Congestion-

aware routing

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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 NetworkingComparisons of COLLs

The Evolution of IP ProductsSoftware and Protocol Requirements

Hardware RequirementsNetwork 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. MPLS enables to COLL behavior.

The pinned-up connection is relatively permanent, thereby allowing for resources to be reserved and allocated. Traffic Engineering, QoS and Congestion Aware Routing

Service Providers with an existing COLL will require MPLS to be a functional replacement.

The charts below reflect that MPLS is providing the key components of a COLL technology.

MPLS and ATM as COLLs

ATM MPLS Connection ID VP / VC (2) Stacked Labels (many)

Connection Method Virtual Circuits

Label Switched Paths (LSPs)

Explicit Routing Designated Transit List

Explicit Route Objects

Path Setup UNI Signaling

CR-LDP or RSVP-TE

To meet QoS requirements, even non-ATM LSRs should provide capabilities similar to ATM switches:

ATM MPLSQueuing Per-VC queuing Per-LSP queuing

TrafficScheduling

Weighted per-VCscheduling

Weighted per-LSP scheduling

QoS Routing 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 over-

subscription) 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

Connection oriented Networking

Traditional Routing IP Routing and forwarding

MPLS Connections for IP

Connection Switching

Connectionless Packet Routing

IP ATM

MPLS

ATM already has the right experience with the necessary algorithms.Connection types: Is your MPLS vendor delivering 1994 technology?

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 ModelMoving to an End-to-end MPLS Network

The Migration Process

AAL5Header Fixed 53 byte MTU

AAL5Header Dynamic MTU up to 16k

PPPHeader Dynamic MTU up to 16k

Encapsulation and MTU Routing Protocol

OSPF, RIP,

IS-IS, BGP

P-NNI

P-NNI

Technology

ATM

F-NNI

POS

ATMCells

ATMCellsF-NNI

Easy migration IP/ATM/cells Today IP/ATM/FNNI HW IP/MPLS/FNNI SW IP/MPLS/POS SW

Each step is a fully functional network.

What is not shown is that you lose your COLL….which is why you need to add MPLS back on top.

The New Services Enabled by an MPLS Infrastructure

Advantages of MPLS NetworkingNew Services Enabled By MPLS

Hybrid Switches Created by MPLSConclusions

Advantages of MPLS network Transport technology independent End to end connections COLL in single control plane

TE TM QoS CR

Greater tunnel hierarchy N2 adjacencies gone Minimizes IP lookup process

Intelligence at edge Core can be simpler switches

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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 VC, VP, POS, MPLS, Frame Relay…

Only ATM switches can operate in SIN mode 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

Edge

4 modes: hop by hop; ATM; MPLS, SIN

PayloadCon ID

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 service, enable multi-application uses: Voice video data

The Effect of Hybrid Switches in the Network Design

Routers’ View of the Network

Full mesh of SPVCs between all Core Routers

Many diverse paths exploited through ATM core

CR

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ATM Switch

Core IP Router

Access Router /AS Border Router

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Conclusions

MPLS promises to be a powerful unification technology Marring the best of IP and ATM

It will take time to meet all high expectation. Functional replacement Network management

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!