HOW ROUTER FORWARD PACKETSHOW ROUTER FORWARD PACKETS

DATA PR IP MAC

ROUTING TABLE

1. PROCESS SWITCHING

PC1 PC2

CACHE MEMORY

ROUTING TABLE

HOW ROUTER FORWARD PACKETSHOW ROUTER FORWARD PACKETS

2. FAST SWITCHING

PC1 PC2

CACHE MEMORY

HOW ROUTER FORWARD PACKETSHOW ROUTER FORWARD PACKETS

3. CEF

If it is send from this network

Send it to this hop

This Hop Has this MAC address

FIB Table ADJ Table

PC2PC1

MPLSMPLS

• Industry standard mechanism

• Forwarding decisions based on layer 2 labels

• Labels can corresponds to : Destination network QoS Outgoing interface

• MPLS is service provider technique.

WHERE DOES THE LABEL GO?WHERE DOES THE LABEL GO?

DATA PR IP MAC

LABEL EXP BS TTL

MPLS LABEL

BITS: 0-19 20-22 23 24-31

DATA PR IP L3 L2 L1 MAC

HOW MPLS WORKSHOW MPLS WORKS

CLIENT2 CLIENT1

12.0.0.0

SERVICE PROVIDER

1. Routing table build.2. A label is assigned and distributed to each SP router3. Each SP router build LIB4. Then each SP router build Action table

2850

32

12 322850

32 28

LIBAction table

CC

AA

BB

Send

s pac

ket t

o 12

netw

ork

Assign

labe

l 32 t

o it

Remove label 32 and

Assign label 28 to it

Send packet to C1

ROUTER ARCHITECTURE WITH MPLSROUTER ARCHITECTURE WITH MPLS

• CONTROL PLANE

-- Where L3 routing protocol exist

-- Where Label exchange protocols exist

• DATA PLANE

-- Also known as forwarding plane

-- Sends data based on L3 or L2 information

-- Take care of label swapping

MPLS TERMINOLOGYMPLS TERMINOLOGY

• Label Switch Router (LSR)/Provider Router

• Edge LSR/Provider Edge(PE) Router

• Label Switch Path(LSP)

• Label Distribution Protocol(LDP)

• Label Information Base(LIB)

Labels match to a network

• Label Forwarding Information Base(LFIB)

What labels should go which directions

HOW DOES MPLS USED?HOW DOES MPLS USED?

1. VIRTUAL PRIVATE NETWORK (MPLS VPN)

2. TRAFFIC ENGINEERING (MPLS TE)

3. QUALITY OF SERVICE (MPLS QoS)

MPLS VPNMPLS VPN

• A Virtual Private Network (VPN) is a private network service delivered over a public (shared) network.

• Two broad categories:

1. Customer-based:

VPN configured on customer located equipment

,IPSec.

2. Network-based:

VPN configured on SP equipment ,MPLS

VPNs

HOW MPLS VPN WORKSHOW MPLS VPN WORKS

Customer 1

SERVICE PROVIDERINTERNET

Customer 2

Customer 1

Customer 2

PE

P

PE

64-bit RD

VRF

ADVANTAGESADVANTAGES

• Provide security by separating address space and routing information of customers

• Spoofing is very difficult to accomplish since LSPs have local significance only

• Used to provide a fully meshed network architecture

• Provide significant cost savings and increased scalability

MPLS TEMPLS TE• The task of engineering the traffic flows in the backbone

network

• The key characteristics of Traffic Engineering are:

- Avoid congestion

- Apply CBSPF for the traffic flows.

- Provide ISPs better to deliver QoS and CoS

• Implementation of TE requires end-to-end virtual paths across the network

• MPLS TE automatically establishes and maintains the tunnel across the backbone, using RSVP.

MPLS-TE ROUTER ARCHITECTUREMPLS-TE ROUTER ARCHITECTURE

• 1. MPLS-TE enabled feature on all the routers in the backbone network

• 2. Flood

• 3. Identifying the congested links.

• 4. At Router R1

a)Resource requirements for establishing LSP is send to LSP Management Module

b) LSP MM, requests CSPF module for computing the complete explicit route (LSP) from R1 to R7

c)LSP MM then triggers the Signaling protocol (RSVP) for establishment of the complete explicit route (LSP) from R1 to R7.

d) On successful establishment LSP MM updates the LIB with the Label bindings.

MPLS TRAFFIC ENGINEERING OPERATIONMPLS TRAFFIC ENGINEERING OPERATION

CONGESTION CONTROLCONGESTION CONTROL

• Two mechanisms: FATE mechanism FATE+ mechanism

• FATE provide rebalancing flows during congestion periods by using priority buffers in LSP routers

• In FATE+ mechanism, the congested LSR makes decision to solve congestion

MPLS QOSMPLS QOS

• MPLS’s connection-oriented nature provides the framework necessary to give quality guarantees to IP traffic

• While QoS and Class of Service (CoS) are not fundamental features of MPLS, they can be applied in MPLS networks where TE is used.

• Two mechanisms: IntServ(Integrated Services) DiffServ(Differentiated Services)

INTSERV(INTEGRATED SERVICES)

DIFFSERV(DIFFERENTIATED SERVICES)

Fine-grained, flow-based mechanism

Coarse-grained, class-based mechanism for traffic management.

RSVP was developed to signal QoS requirements across a network

Operates on the principle of traffic classification, where each data packet is placed into a limited number of traffic classes

Offers traffic bandwidth guarantees

Does not provide guarantees

Not very scalable or practical to operate across large networks

DiffServ architecture is a scalable

INDIA TV DELIVERS THE NEWS WITH TATA COMMUNICATIONS MPLS SERVICE

• A major broadcaster in India, which operates an independent news agency with bureaus and studios throughout the country

• Uses MPLS VPNs as: - Connectivity difficult reach areas of the country

- Increased reliability over previous solution - Lower operational costs - Live 24X7 news and video streaming feeds from virtually any location in India - Ample capacity for future expansion

Connection to various offices through MPLS VPN

COMPARISON OF MPLS VERSUS ATM

• Both MPLS and ATM provide a connection-oriented service

• MPLS is able to work with variable length packets while ATM transports fixed-length cells.

• ATM network adds significant complexity and overhead to the data stream.

• An MPLS connection is unidirectional,2 LSPs are required for connectivity on the other hand, ATM are bidirectional

WILL MPLS REPLACE ATM?

• MPLS was not designed to replace ATM

• SPs migrate their ATM networks to one based on MPLS

• MPLS can co-exist with ATM switches and eliminate complexity by mapping IP addressing and routing information directly into ATM switching tables

• MPLS provides the control component for IP on both the ATM switches and routers.

EXAMLE OF MPLS VPN over ATMEXAMLE OF MPLS VPN over ATM

CONCLUSION

• MPLS is packet forwarding technique .

• Makes router as efficient as switch.

• Most commonly used as VPN.

• Easily used with technologies like Frame relay, ATM

• Research is going on IPSec based MPLS VPN to increase data security

REFRENCESREFRENCES

• XIXIA Whitepaper. “Multi-Protocol Label Switching (MPLS) Conformance and Performance Testing”,2004.

• IRM research Whitepaper Thorsten Fischer. “MPLS Security Overview”,2007.

• ITU-T - IETF Joint Working Team Dave Ward, Malcolm Betts, ed. “MPLS Architectural Considerations for a Transport Profile”,2008.

• Cisco Systems Whitepaper. “Analysis Of Mpls-based Ip Vpn Security: Comparison To Traditional L2vpns Such As Atm And Frame Relay, And Deployment Guidelines”,2008.

• Tata Communication Whitepaper. “Major TV Broadcaster Delivers the News with Tata Communications MPLS Service”,2007.