Multi-protocol Label Switching

Jiang Wu

Computer Science Seminar5400

Agenda

Background– Routing in Internet Protocol (IP) Networks– Asynchronous Transfer Mode (ATM)– IP Over ATM Models

Multi-protocol Label Switching (MPLS) MPLS using ATM Switching Feature Research Q & A

Traditional Routing In IP Networks

H1

SourceDestination Data

H2

H3

H4

H5

H6

H7

H8

Destination Next HopA.B.C.* Rn

Routing Table

R1

R5

R6 R7

R8

R4R3

R2

Traditional Routing In IP Networks

IP address Routing Algorithm

– e.g. Open Shortest Path First (OSPF) Characteristics:

– Connectionless– Hop-by-hop– IP Address Parsing at Each Hop– Routing Table Query at Each Hop

Traditional Routing In IP Networks

Issues: CPU Speed: 10 times improvement per decade Data Communication: more than 100 times

improvement per decade Routers become the bottlenecks of the Internet

ATM

H1

H2

SETUP

VPI/VCI

VPI Table

VPI Table

VPI Table

VPI Table

In OutPort VPI Port VPI

VPI Table

H1

H2

RELEASE

VPI Table

VPI Table

VPI Table

VPI Table

ATM

ATM

ATM address Routing and Signaling

– e.g. Private Network-to-Network Interface (P-NNI)

Connection Oriented Cell Switch by hardware High speed

IP Over ATM Models

Overlay Model Peer-to-Peer Model

– MPLS

MPLS Architecture

H1

H2 H4

H3

LSR

LER

MPLS Domain

MPLS Components

Label Edge Router (LER) Label Switching Router (LSR) Forward Equivalence Class (FEC) Label Label-Switched Path (LSP) Label Distribution Protocol (LDP)

MPLS Component: LSR

In the core of MPLS networks High-speed router Switch data traffic within MPLS domain

MPLS Component: LER

At the edge of MPLS networks Assign and remove label Transport data traffic between MPLS domain

and IP networks

MPLS Component: FEC

Representation of a group of packets that share the same requirement for transport– e.g. packets with same destination IP address prefix

MPLS Component: Label

Short fixed length identifier Assigned to every packet Carried in layer 2 header Of local significance

MPLS Component: LSP

A path to transport packets within MPLS domain

Set up prior to data transmission Unidirectional

MPLS Component: LDP

Distribution label information to LSR

MPLS Operations

Label creation and distribution Table creation at each router LSP creation Label insertion/table lookup Packet forwarding

Label creation and distribution

H1

H2 H4

H3

LSR

LER

FEC HopIn Label LabelFEC Hop Label

LSP

Label Insert, Swap and Remove

H1

H2 H4

H3

LSR

LER

FEC HopIn Label LabelFEC Hop Label

IP Label IPIPLabel IP

MPLS

IP address Routing Algorithm

– Same as IP network

LDP Support ATM, Frame Relay, …

MPLS using ATM

In OutPort VPI Port VPI

VPI Table

Cell Switch Hardware

OSPF, LDP

ATM-LSR

Future Research

ATM

SONET

IP

WDM WDM

IP

MPLS

GMPLS

Q & A

Thanks