Mpls the magic behind the myths
Sponsored Links
This presentation is the property of its rightful owner.
1 / 19

MPLS: The Magic Behind the Myths PowerPoint PPT Presentation


  • 57 Views
  • Uploaded on
  • Presentation posted in: General

MPLS: The Magic Behind the Myths. Grenville Armitage (author) Scott Crosby (presenter). Problems with IP. No Quality of Service Necessary for converged network Realtime voice Best-effort data High priority transactions (ATM, control, VC, …) Performance Scalability

Download Presentation

MPLS: The Magic Behind the Myths

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


MPLS: The Magic Behind the Myths

Grenville Armitage (author)

Scott Crosby (presenter)


Problems with IP

  • No Quality of Service

    • Necessary for converged network

      • Realtime voice

      • Best-effort data

      • High priority transactions (ATM, control, VC, …)

  • Performance Scalability

    • Expensive prefix match for each packet

  • Traffic Engineering


Problems with IP

  • Tunneling

    • Tunnel IP over non-IP intermediate

      • IP over IP over ATM?

IP Network

IP Network

ATM

IP Network

IP Network


Problems with IP

  • Tunneling

    • Tunnel IP over non-IP intermediate

    • Virtual Private Network

Duncan EE

IP Network

Abercr. CS

IP Network

Abercr. EE

IP Network

Duncan CS

IP Network


Problems with IP

  • Tunneling

    • Tunnel IP over non-IP intermediate

    • Virtual Private Network

    • Traffic Engineering

IP Network

IP Network

IP Network

IP Network


What is MPLS?

  • Virtual circuit layer underneath IP

    • Virtual circuit = virtual wire = label switched path

IP Network

(Voice)

IP Network

(ATM)

IP Network

(Data)

MPLS

(Virtual Point-to-Point Circuits)

Physical Infrastructure

(Point-to-Point Circuits)


What is MPLS?

  • Offer service above IP

    • Converged network

      • Realtime voice

      • Best-effort data

      • High priority transactions (ATM, control …)

    • On the same physical infrastructure

  • Hop-by-hop QoS differentiation


5

13

13

13

5

5

Payload

Payload

Payload

Payload

Payload

Payload

How Does MPLS Work?

  • Packets are tagged and routed based on tags.

    • All traffic with the same label treated the same

IP Routing

Layer

IP Routing

Layer

LSR

Payload

Payload

LER

LER

Payload

Payload


Other Features of MPLS

  • Tag forwarding distinct from IP forwarding

    • May make non-shortest paths

    • Tag routing linked to IP routing

IP Forwarding

LER

(Perform Tagging)

LSR Cloud

(Forward by tag)

IP Forwarding

LER

(Remove Tag)

LSR Cloud

(Forward by tag)


13

Payload

MPLS Header

  • Lightweight

    • 8 bit TTL

    • 20 bit label tag

    • 3 bit QoS tag

    • 1 bit stack

      • Indicates last LSR tag

      • Allows heirarchial tagging

13

Payload

5

13

Payload

8

13

Payload


Provisioning vs. Signalling

  • Signalling

    • Seconds

  • Provisioning

    • Minutes to days

  • Separate control message protocol

    • Distribute labels and forwarding info

    • RSVP

    • Label Distribution Protocol


Comparing MPLS to IP

  • IP over MPLS vs IP only

    • Qos

    • Performance

    • Tunneling

    • VPN

    • Traffic Engineering


MPLS vs IP: QoS

  • MPLS

    • Per hop QoS

    • Using labels to prioritize

      • 20 bit identifier space

  • IP

    • Per hop QoS

    • Use IP&TCP header

      • 104 bit identifier space


MPLS vs IP: Performance

  • MPLS

    • Forward on short tags

    • Not prefix match on address

  • IP

    • Routers can forward at gigabit/s


MPLS vs IP: Tunneling

  • MPLS

    • Lightweight tunnels

      • 32 bit header

  • IP

    • Heavyweight tunnels

      • ~160 (?) bit header


MPLS vs IP: VPN

  • MPLS

    • Lightweight

      • 32 bit header

    • No security

  • IP

    • Heavyweight

      • ~160 (?) bit header

    • No security

      • (without IPSEC)


MPLS vs IP: Traffic Engin.

  • MPLS

    • Arbitrary (non-shortest) paths

    • Virtual circuits

    • MPLS routing linked to IP routing

    • Flexible aggregation

  • IP

    • Route announcement manipulation

    • Path cost manipulation


MPLS vs IP: Future QoS

  • MPLS

    • Propagate QoS between networks

    • RSVP

  • IP

    • Propagate QoS between networks

    • RSVP


Compelling Advantages

  • Traffic engineering

    • Management engine

      • Connectivity

      • Policy

      • Constraint based routing

      • Construct virtual topology

        • LSP’s

        • Labels


  • Login