Why SDN and MPLS?

Saurav Das, Ali Reza Sharafat,Guru Parulkar, Nick McKeown

Clean Slate CTO Summit9th November, 2011

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Why do Service Providers use MPLS?

Really about 2 services

MPLS Services

MPLS VPNs MPLS - TE

Motivation

Highly profitable

No easy way

Older ways not used

Motivation

Deterministic Behavior

Efficient Resource Utilization

Older ways not used

What is Traffic Engineering?

Steering traffic to where the bandwidth is…• good for the traffic - less congestion• good for the network - better resource

utilization

MPLS Solution: • Create tunnels routed over under-utilized

parts of the network • Route traffic through the tunnels

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Video of a Demonstrationshowing MPLS-TE service with SDN/OF

www.openflow.org/videos

OSPF-TE

RSVP-TE

LDP I-BGP

LMP MP-BGP

Label Switched Path (LSP)

PUSH SWAP POP5

P

OSPF-TE

RSVP-TE

LDP I-BGPOpenFlow

NETWORK OPERATING SYSTEM

Routing Discovery Label Distribution Recovery

TE

LMP MP-BGP

PUSH

Simpler Data Plane

Simpler Control Plane

Services

Network Applications

SWAP POP

Label Switched Path (LSP)

Provide the Services without the Complexity!

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State Distribution Mechanisms

Switch Operating

System

DistributedNetwork Functions

IGP- Route Advert, Link-State

OSPFv2

TE Label Distribution

RSVP-TE

VPN-IPv4 Route Advert

MP-BGP

E-BGP learned Route Advert

I-BGP + RR

PE Label Distribution

LDP

Distributed Network Functions each with their own

State Distribution Mechanisms

Motivation

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1. MPLS doesn’t come cheap• MPLS additional feature on

complex core-routers• Need to support many

protocols

2. MPLS doesn’t come simple• IP/MPLS Control plane

exceedingly complex

OSPFv2

RSVP-TE

MP-BGP

I-BGP + RR

LDP RSVP-TE

MP-BGP

I-BGP + RR

LDPOSPFv2

RSVP-TE

MP-BGP

I-BGP + RR

LDP

Juniper Cisco Brocade

TE TE TE

Auto-RouteAuto-Bandwidth

PrioritiesLoad-Share

DS-TEFRR

Re-opt

Auto-RouteAuto-Bandwidth

PrioritiesLoad-Share

DS-TEFRR

Re-opt

Auto-RouteAuto-Bandwidth

PrioritiesLoad-Share

DS-TEFRR

Re-opt

Motivation

3. Slow pace of Innovation8

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Providing MPLS Services with SDN/OF

OpenFlow

NETWORK OPERATING SYSTEM

Routing Discovery Label Distribution Recovery

TE 2.0

Simpler Cheaper

Multi-VendorData Plane

(1)

Simpler Control Plane

(2)

Services / Network Applications

(3)

SWAP POPPUSH

Application/Service Viewpoint

3 Examples of SDN Benefits:

1. Programmability & Simplicity

2. Extensibility

3. Global -Optimization

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R3

R6

R2R4

R5

R1

Re-routing Packets into Tunnels

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Exposing tunnels to OSPF or IS-IS• N2 problem• Strictly avoided

IP routing (SPF)

TE-LSP routing (CSPF)

PBR/FBF, AutoRoute

Link-state: cost, up/downTE-Link-state: weight, attributes, reservations

Link-state: cost, up/down

R3

R6

R2R4

R5

R1

Re-routing Packets into Tunnels

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Tunnels not Represented here

AutoRoute

Destination Router Next-Hop Total-Cost

R4 R4, OutIntf 12 10

R6 R6, OutIntf 9 10

R2 R4, OutIntf 12 20

R2 R6, OutIntf 9 20

Destination Router Next-Hop Total-Cost

R4 R4, OutIntf 12 10

R6 R6, OutIntf 9 10

R2 TunnIntf T1 20

R3

R6

R2R4

R5

R1

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Routing Table in R5

AutoRoute

IP dest-prefix

via dest-router(in domain)

next-hopnext-hop is tunnel

Automated but Inflexible

Policy Based Routing

IP dest-prefix

via dest-router(in domain)

next-hopHeader-field-matchnext-hop is tunnelor something else

Flexible butNot Automated 14

SDN based Routing

IP routing (SPF)

TE-LSP routing (CSPF)

Static-routes, PBR/FBF, Autoroute

Link-state: cost, up/downTE-Link-state: weight, attributes, reservations

Link-state: cost, up/down

Programmability =>Flexibility + Automation

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Default SPF

Routing

IP network

TE-LSP Routing(CSPF)

VoIP traffic

Routing

Customer traffic

Routing

Load Sharing

Tunnels Represented

here

NOX core(Connection Handler, Event engine)

Switch-API

GUI API

(LAVI)

GUI(ENVI)

OpenFlow protocol

To switches..

Link Discovery

IP Topology

TE-LSP Routing (CSPF)

TE-LSP Configuration Bw. Res. & Priorities

Label DBTE tunnel DB

Packet-flow DB

Controller

TE Applications

Map Abstraction

Network API

TE-LSP Statistics & Auto-Bandwidth

Network API

Default SPF Routing Load SharingTraffic-type Aware Routing

Packet-flow Routing Applications

Controller Internals

~4000 Lines-of-Code

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Application/Service Viewpoint

3 Examples of SDN benefits:

1. Programmability & Simplicity

2. Extensibility

3. Global -Optimization

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L3-VPN

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• 2 new protocols – LDP and MP-BGP

• Implementation in each router

• More code to tie VPN service to protocols

• … and protocols to other protocols

• CLI changes + configuration

• … and eventually standardization

What would it take in today’s networks?

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NOX core(Connection Handler, Event engine)

Switch-API

GUI API

(LAVI)

GUI(ENVI)

OpenFlow protocol

To switches..

Link Discovery

IP Topology

TE-LSP Routing (CSPF)

TE-LSP Configuration Bw. Res. & Priorities

Label DBTE tunnel DB

Packet-flow DB

Controller

TE Applications

Map Abstraction

Network API

TE-LSP Statistics & Auto-Bandwidth

Network API

Default SPF Routing VPN RoutingTraffic-type Aware Routing

Packet-flow Routing Applications

What did it take with SDN?Just this!!

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Providing MPLS Services with SDN/OF

OpenFlow

NETWORK OPERATING SYSTEM

Routing Discovery Label Distribution Recovery

TE 2.0 VPNs 2.0

Simpler Data Plane

(1)

Simpler Control Plane

(2)

Services / Network Applications

(3)

Optimized FRR/ AutoBw

MPLS-TP Control

Multi-layer Control

SWAP POPPUSH

Application/Service Viewpoint

3 Examples of SDN Benefits:

1. Programmability & Simplicity

2. Extensibility

3. Global -Optimization

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Auto-Bandwidth/ Re-Opt Timers

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Churn

Source: NANOG 24

R3

R6

R2R4

R5

Local View Local Optimization

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Global View Global Optimization

OpenFlow

NETWORK OPERATING SYSTEM

Routing Discovery Label Distribution Recovery

TE 2.0 VPNs 2.0

2. Dynamically Update

Forwarding State

1. Periodic, Online

Global-Opt

Optimized FRR/ AutoBw

MPLS-TP Control

Multi-layer Control

SWAP POPPUSH

Why SDN and MPLS?

Simpler Control – Eliminate protocols, decouple network-functions from state-distribution mechanisms

Simpler, Cheaper MPLS data-plane with SDN control-architecture

Service Innovation – Programmability, Extensibility & Global-Optimization.

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Open vSwitchwith standard

MPLS data plane

Prototype System

Network Operating System (NOX)GUI (Envi)

showing real-timenetwork state

Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)Open vSwitch(with MPLS)

Open vSwitchwith standard

MPLS data plane

OpenFlow

MPLS GUI MPLS API MPLS StatsCSPF Routing

MPLS-TEAuto – route; Auto – bandwidthTraffic – aware LSPs; PrioritiesTE-LSP configuration

Mininet Environment 28