mpls to gmpls

8/7/2019 MPLS TO GMPLS

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-PRESENTED BY-

SUNAME PRASHARROLL NO : 296|ECE|2007

COLLEGE : MIET/ JAMMU UNIVERSITY


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MPLS Introduction

Motivation

MPLS Basics

Components and Protocols Operation

Applications including GMPLS

Advantages and Disadvantages


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Motivation

IP

The first defined and used protocol

It usually works in packet switching environment.

but there are disadvantages


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Motivation (cont.)

IP Routing disadvantages

Connectionless

- e.g. no QoS Each router has to make independent forwarding decisions

based on the IP-address

Large IP Header

- At least 20 bytes


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Motivation (cont.)

ATM

connection oriented

- Supports QOS

Fast circuit switching with fixed length packets(cells)

integration of different traffic types (voice, data,video)

but there are also disadvantages


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Motivation (cont.)

ATM disadvantages

Complex

Expensive Not widely adopted


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Motivation (cont.)

Idea: Combine the

forwarding algorithm

used in ATM with IP.


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MPLS BASICS

MPLS is a versatile solution to address the

problems faced by present day

networks(usually IP networks) including speed,

scalability, QOS and traffic engineering.

Standard approved technology by IETF


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MPLS BASICS

Multi Protocol Label Switching is arranged

between Layer 2 and Layer 3


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MPLS BASICS (cont.)

MPLS is arranged between layer 2 and layer 3 protocols of

the OSI

model thats why it is also called as layer 2.5protocol.

Works with IP,ATM and frame relay network protocols

thats why it is called as multiprotocol.

It can works in both circuit switching and packet switchingenvironment.

Unlike IP networks , MPLS are connection oriented and

packets are routed along pre-configured LSPs.


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MPLS BASICS(cont..)

- MPLS is based on the concept of label

switching : an independent and unique

label is added to each data packet and this

label is used to switch and route the packet

through the network

- MPLS uses the same routing and hostaddressing schemes as IP networks.


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COMPONENTS AND PROTOCOLS

LER label edge router

LSR label switching router

FEC - forward equivalence class Label- associates a packet to a FEC

LSP- label switched path

LDP- label distribution protocol.


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Label edge router

LER LER is the device that operates at the edge of

the MPLS network.

LER plays a very important role in theassignment and removal of labels, as traffic

enters or exits an MPLS network.


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Label Switching Router -

LSR

An LSR is a high speed router in the core of an

MPLS network that participates in the

establishment of the LSPs(label switched path)

using appropriate label signaling protocol.

ATM switches can be used as LSRs without

changing their hardware.


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Label

A labelis a short, fixed-length value carried in thepacket's header to identify a forwarding

equivalence class (FEC). These labels are arranged in the form of stack

known as label stack.

Label associates a packet to a FEC.


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Label

Generic label format


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Forward Equivalence Class

-FEC

Is a representation of a group of packets that

share the same requirements for their

transport.

The assignment of a particular packet to a

particular FEC is done just once (when the

packet enters the network).


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Label-Switched Paths -LSPs

Within an MPLS domain, a path is set up for a

given packet to travel based on an FEC.

The LSP is set up prior to data transmission.


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LSP Details

MPLS provides two options to set up an LSP

hop-by-hop routing

Each LSR independently selects the next hop for a given FEC.LSRs support any available routing protocols (OSPF, ATM ).

explicit routing

Is similar to source routing. The ingress LER specifies the list of

nodes through which the packet traverses.

The LSP setup for an FEC is unidirectional. The return

traffic must take another LSP!


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MPLS Operation

The following steps must be taken for a data

packet to travel through an MPLS domain.

label creation and distribution

Label information base creation using LDP

label-switched path creation

Label information base creation

packet forwarding


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MPLS Operation Example


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Packet Forwarding

Packet forwarding

LER1 may not have any labels for this packet as it is

the first occurrence of this request. In an IP

network, it will find the longest address match to

find the next hop. Let LSR1 be the next hop for

LER1.

LER1 will initiate a label request toward LSR1.

This request will propagate through the network as

indicated by the broken green lines.


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Packet Forwarding (cont.)

Each intermediary router will receive a label from itsdownstream router starting from LER4 and going

upstream till LER1. All these routers will update their LIB table for this FEC.

The LSP setup is indicated by the broken blue linesusing LDP or any other signaling protocol.

LER1 will insert the label and forward the packet toLSR1.


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Packet Forwarding (cont.)

Each subsequent LSR, i.e., LSR2 and LSR3, will

examine the label in the received packet, replace it

with the outgoing label and forward it. When the packet reaches LER4, it will remove the

label because the packet is departing from an MPLS

domain and deliver it to the destination.

The actual data path followed by the packet is

indicated by the broken red lines.


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APPLICATIONS

Traffic engineering ( the ability of network

operators to dictate the path that traffic takes

through their network) and VPN support are

the examples of two key applications where

MPLS is superior to any currently available IP

technology.


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GMPLS

MPLS is being expanded for more general

applications in the form of GMPLS with the

application in optical and time-division

multiplexing network.

GMPLS is conceptually similar to MPLS, but

instead of using an explicit label for a given

FEC , some physical properties(time slot,wavelength etc..) of the received data stream

is used to deduce which LSP it belongs to.


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MPLS Advantages

Improves packet-forwarding performance in

the network

Supports QOS and COS for servicedifferentiation

Supports network scalability

I

ntegratesI

P and ATM in the network


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MPLS Disadvantages

An additional layer is added

The router has to understand MPLS


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Thank you..!

...

mpls to gmpls

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