MPLS cisco QOS VPN full mpls migration

Migration Example 1: Separate Networks -> Dual Backbones• Surround ATM network with IP+ATM Edge Switches • Link them to both backbones • Carry IP services on router backbone & ATM ser

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MPLS Migration &

Deployment

Jeremy Lawrence (With a few slides by Tom Downey & Rob

Redford)

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• Full Meshes & Scalability

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Why Migrate to MPLS?

3

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Different Solutions for LAN and WAN

Multiprotocol over ATM

(MPOA)

MPL S

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Label Switch Routers (LSRs):

ATM Switches or

Routers

Edge Label Switch Routers (LSRs) Customer sites

run ordinary IP

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Key MPLS Capabilities

IP/ATM Integration Traffic Engineering

IP Multicast IP CoS

RSVP

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Traditional IP over ATM

• Put routers around the edge of an ATM network

• Connect routers using Permanent Virtual Circuits

• This does not provide optimal integration of IP

and ATM

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Fully support IP, along with

Frame Relay and ATM, on

shared ATM backbone

Provides optimal IP

forwarding capability on an

ATM network

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MPLS Brings IP and ATM Together

• Overhead limits performance

and efficiency

Data path

IP+ATM Switch

PNN

I MPL S

IP

Cisco IP+ATM

IP Ser vi ce s

AT M Ser vi ce s

• No complex translation

• Full IP and ATM capabilities

• Built-in IP routing

Cisco IP+ATM

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IP over ATM Integration MPLS: IP Fundamentals

• Full support for IP

CoS, soon RSVP, & IP

multicast

IP Multicast IP CoS

RSVP

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Network-Wide Delivery of Services

• MPOA, similar approaches work only across network cores with:

ATM Switches

• No delivery of advanced services like VPNs over network cores with:

Packet-over-SONET/SDH/WDM Routers

Switch-Routers

• Very limited migration and interoperability options

?

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Network-Wide Delivery of Services

VPNs across networks with all equipment types:

ATM Packet-over-SONET/SDH/WDM Switches

Routers Switch-Routers

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300 Mbps Traffic Flow

155 Mbps Fiber Link Link Failure

No Physical Link

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Single carrier network supporting multiple customer IP VPNs

Separately engineered

customer private IP

networks

MPLS Network

Virtual Private Networks

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Corp B Site 1

Corp A Site 3

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Common Misconceptions

compared to ordinary IP networks

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Common Misconceptions

• Myth: IP has poor Quality-of-Service options,

and MPLS has much better QoS

• Reality: IP networks with DiffServ and RSVP

have largely the same QoS options as MPLS (ATM or Packet-based)

• MPLS provides only a few minor QoS

advantages compared to state-of-the-art IP networks

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MPLS & QoS: A Few Minor

Advantages

packet-based IP for higher-CoS traffic, e.g VOIP This is

significant only with mixed voice and data traffic at

lower trunks speeds: E3/T3 trunks and below.

QoS

but this function is similar to a full RSVP-on-IP

implementation

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• Keep up with Internet growth

• Reduced complexity for lower operational cost

• Better utilization of trunks means lower costs

• Optimise performance of existing networks

• New revenue opportunity for SPs

• Scalability for lower operational costs and faster

rollout

• L2 privacy and performance for IP

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IP+ATM Networks &

Dual-Backbone Networks

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IP+ATM Edge

Switch

IP+ATM Core Switch

• All services are fully

integrated on one set of switches and one set of links

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MPLS

Frame Relay/ATM PVCs & SVCs

Unified access to

multiple services

Each service runs

“natively” on the ATM Switches

- no overlays

- resources partitioned by service

Each service runs

“natively” on the ATM Switches

- no overlays

- resources partitioned by service

IP+ATM Networks

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MPLS & IP services

Frame Relay/ATM PVCs & SVCs

IP+ATM Edge Switch

Different DLCIs or VCIs on the

same customer link can go to

different

Different DLCIs or VCIs on the

same customer link can go to

different

IP+ATM Edge Switches

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Common Situation in Carriers:

Separate Networks

• IP part of the carrier has router network, typically router and dial access

Often, this part uses Cisco equipment.

• Router network may be running MPLS & VPNs

• Traditional data part of the carrier has a FR/ATM

network This part often has non-Cisco equipment.

Router Network

ATM Network

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Migration Example 1: Separate Networks -> Dual Backbones

• Surround ATM network with

IP+ATM Edge Switches

• Link them to both backbones

• Carry IP services on router

backbone &

ATM services on ATM backbone

• Multiservice Acceleration Program (MAP) allows 120 days free trial!

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• From a single link, a

customer can access both

DLCI into PVC

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Dual Backbones: Summary

• Dual backbone networks are an alternative to

IP+ATM networks

• With an IP+ATM edge switch, dual-backbone

networks can offer the same services as

IP+ATM networks

• The Multiservice Acceleration Program allows

120 days free trial of IP+ATM edge switches to qualified customers

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Migration Technologies 1: PVCs

• PVCs can be used to

carry ordinary IP (RFC 1483) from CPE to

Edge LSRs: ‘backhaul’

• PVCs can be used to

connect Edge LSRs or other Packet-based

LSRs over traditional ATM switches

MPLS-over-PVCs

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MPLS-over-PVCs

• MPLS-over-PVCs connects

packet-based LSRs to each other (All edge LSRs are packet-based LSRs.)

• MPLS-over-PVCs can’t terminate on ATM-LSRs

• The BPX 8600 is an

exception: the Label Switch

Controller has limited ability

to terminate MPLS-over-PVCs

Edge LSR ATM-LSR

MPLS-over-PVC

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Migration Technologies 2: VP

Tunnels

• VP Tunnels (or “Virtual

Trunks”) are PVP connections

• VP Tunnels can connect

to LSRs of any type, including ATM-LSRs

• Exceptions: limitations on some particular LSRs and

line cards See Designing

ATM MPLS Networks.

LSR of Any Type LSR of Any Type

VP Tunnel

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Migration Example 2: Introduction

has an ATM network, but does not yet want to upgrade the edge switches to IP+ATM Edge Switches

Packet-Based MPLS

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Migration Example 2: Starting Point

LSR Edge LSR

• Application: early trials of

MPLS VPNs in an existing

SP ATM network

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Migration Example 2: Next Step

Edge LSR

• Replace or upgrade some

edge switches to Edge LSR capability.

• Link the edge LSRs to the

MPLS part of the network

• Remove some backhaul

PVCs

• Application: later deployment

of MPLS VPNs into an existing ATM network

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Migration Example 2: Final Stage

remaining edge devices

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has an ATM network, and does want to upgrade the edge switches to IP+ATM Edge Switches

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• Run packet-based MPLS over PVCs

• Has the same scaling issues as an ordinary IP overlay

• Mesh is troublesome to design What should QoS parameters be?

• Application: support of VPNs in an existing ATM Network

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• Run ATM MPLS over VP Tunnels between Edge LSRs

• Similar issues to MPLS-over-PVCs

• Application: support of VPNs in an existing ATM

Network

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` One-armed’ ATM-LSR

Simpler mesh of PVPs

Non-MPLS

ATM Cores

Add ATM MPLS Functionality to Some Switches

Migration Example 3: Intermediate

Stage

• Migrate to VP Tunnels, if necessary

• Add ATM MPLS to some existing switches, or add new switches

• PVP mesh is broken into smaller meshes: aids scalability,

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Migration Example 3: Final Stage

• Add more ATM-LSRs for optimum scalability & simplicity

• Ordinary ATM connections can still be used through ATM Label

Switches

• Parts of the network can still use ordinary ATM switches, if required

VP tunnels are not required between adjacent ATM-LSRs

Ordinary ATM

switch, if required

ATM-LSRs

Ordinary ATM Connection

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ATM network, and does want to upgrade the edge switches to IP+ATM Edge Switches

Dual Backbones

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ATM links

MPLS-over-PVCs

Non-MPLS ATM Core

Migration Example 4: Starting Point

ATM Network

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Migration Example 4: Intermediate

Stage

• Add packet-based LSRs

• PVC mesh is broken into smaller meshes: aids

scalability, efficiency, configuration (but this solution is

Packet-Based LSR

Simpler Mesh

of PVCs

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Migration Example 4: Later Stage

the Edge LSRs to them

Packet-Based MPLS Network

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• Can be used in variants

of all the migration examples shown

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Other Alternatives

• MPLS transport mechanisms may be combined in many

other ways

• A Label Switch Controller can also acts as an LSR or Edge

LSR, and may terminate PVCs, PVPs or Packet-over-SDH

ATM-LSR with

LSC

SONET/SDH or WDM

Packet-Over-links

Packet-based

LSRs PVC mesh

PVP mesh

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Routing Planning Issues

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Routing Protocol Choices

• A provider’s MPLS network should use either OSPF

or IS-IS as its Interior Gateway Protocol

• Other IGPs can be used with MPLS, but won’t

support MPLS Traffic Engineering

• Migrating an existing network to IS-IS or OSPF may

be required before enabling MPLS support

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ATM-LSRs and

Packet-based LSRs can act as

Area Border Routers, but

with limitations

Area 0

Area 2 Area 1

OSPF & IS-IS Design Constraints

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Area Border Routers

At LSR-based Area Border Routers:

PE routers must not be summarized

routes at all may be summarized

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MPLS Deployment Options

Available Now

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access lines

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BPX 8650 or MGX8850/PXM-45 network without MPLS switching

MGX 8850/PXM-1

MGX 8850

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BPX 8650 network with MPLS switching

MGX 8850/PXM-1

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Option 3: Details

PVP cross connects are established on the

PXM-1 No virtual trunk configuration on the

PXM-1.

ATM MPLS Links

BPX 8650

1 Configure a UNI or NNI link (not

a feeder trunk) between the MGX

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Option 3: More Details

UNI or NNI link carrying MPLS VP Tunnels

Feeder trunk carrying AutoRoute connections

• If both AutoRoute PVCs and MPLS LVCs are carried between the

MGX & BPX, then two ATM links are required:

Feeder trunk for AutoRoute UNI or NNI link for MPLS

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Option 4: ATM MPLS with

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Option 5: Packet-Based MPLS With

Router Edges

LSRs: 3600, 4700,

7200, 7500, and/or 12000

Edge LSRs: 3600,

4700, 7200, and/or

7500

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Option 6: Packet-Based MPLS MPLS with MGX 8850 Edge

PXM acting as PVC switch

MPLS-over-PVCs

PoS MPLS Links

GSR 12000 (or 7200/7500) network running MPLS

MGX 8850 ATM link carrying PVCs

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Full Meshes & Scalability

61

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• Run packet-based MPLS over PVCs or PVPs (“VP Tunnels”)

• Has the same scaling issues as an ordinary IP overlay

• Application: support of VPNs over an existing ATM Network

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Full Mesh Problems

• ATM switches do not run IP routing (OSPF,

re-IP link failures can cause a storm of routing updates

Traffic scales as N 3

• Limit without work-arounds: about 50 edge

LSRs

• Another issue: each PVC on an Edge LSR

uses 1 Interface Descriptor Block (IDB)

Layer 3 View Physical View

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Work-Arounds & Scaling

3 Partial Mesh

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` One-armed’ ATM-LSR

Simpler mesh of PVPs

Non-MPLS

ATM Cores

Add ATM MPLS Functionality to Some Switches

1(a) VP Tunnel Network With ATM

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1(b) PVC Network Divided by Core

Routers

Simpler mesh of PVCs

Add Packet-based Label Switch Routers

with ATM interfaces

• Add some router-based LSRs (Cisco 7500, 12000) to core

• PVC mesh is broken into smaller meshes, each with up to

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1 Separated Meshes: Evaluation

Meets IP routing scalability requirements Reduces complexity of meshes, dimensioning problems, etc Reduces IDB requirements on Edge LSRs somewhat

Requires additional equipment The performance requirements on the core LSRs may be infeasibly high.

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2(a) ATM MPLS

• Add more ATM-LSRs for optimum scalability & simplicity

• Ordinary ATM connections can still be used through ATM Label

Switches

• Parts of the network can still use ordinary ATM switches, if

VP tunnels are not required between adjacent ATM-LSRs

Ordinary ATM

switch, if

required

LSRs

ATM-Ordinary ATM Connection

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3 Partial Mesh

Partial mesh

of PVCs: some links ‘missing’ Non-MPLS

ATM Core

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3 Partial Mesh: Evaluation

Pros

each router, guaranteeing network stability.

traffic per edge LSR) will tend to increase as the network grows.

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