What is MPLS (Multiprotocol Label Switching)

MPLS acronym stands for Multiprotocol Label Switching. Multiprotocol Label Switching is a protocol mainly designed to speed up and shape the network traffic flow. It is mainly designed to increase the speed of network where there is a heavy usage.

Multiprotocol Label Switching (MPLS) is an advanced technology used in many of the telecommunications networks.  The main aim is to use short path in the routing cycle instead of using longer path thereby saving time and reduce the traffic flow in the network. The routing cycle is made simple by eliminating some of the complex processes. Multiprotocol Label Switching is mainly important for the improvement of the quality of services.

Multiprotocol Label Switching is flexible which is used to divert the traffic inflow. It is easy for the operators to handle any high traffic. This technology integrates two other technology and it is intermediate between them.

Multiprotocol Label Switching is a part of the network, Label switching protocol, routing protocol.

History of MPLS (Multi-protocol label switching)

  • The history of MPLS dates long back to 1994 when Toshiba introduced label switching.
  • In 1996 Ipsilon networks management proposed IFMP
  • Traffic engineering was introduced in 2006
  • In 2001 first MPLS RFCs was released
  • In 2009 label switching multicast was formed
  • In 2011 MPLS transport profile was developed.

Components of Multiprotocol Label Switching:

     The components of Multiprotocol Label Switching includes a combination of the components of layer 2 and layer 3. So MPLS is an intermediate technology of layer 2 and layer 3.

Some of the components of Multiprotocol label switching are

  • Label Switched Path(LSP)
  • Label Switched Routers (LSR)
  • Label Distribution Protocol (LDP)

Label Switching:

The traditional model used in IP model where each router performs routing based on its routing table and forwards its directions to the next hop. The routing decisions are made by the router independently till the arrival of final destination.

Whereas in Label switching the first device performs routing and ends in a final destination surpassing others routines. A label is designed by the router and this helps in redirecting the traffic. So there is no need of using any other lookups. At the final destination, the router label is removed. This is the mechanism behind Label Switching.

Advantages of Label Switching

  • Used to reduce IP routing lookups
  • Label switching lookups are used in exact matching
    • With the help of Label Switching the performance was very high. Also, the routing is distributed to the routers where there is lower speed.
  • Relatively 10 million IP routing can be done in second which is easy and cheap.
    • So the cost of the router and exact matching is cheaper and easy.

Uses of Multiprotocol Label Switching:

  • Traffic engineering:
    • Mainly used to increase the speed and shape the network traffic flow.
    • Able to control the traffic routed on your network
    • It is used for prioritizing the various services.
    • Used for prevention of congestion of the network
    • Used for managing high load of traffic
    • Also, separates the heavy traffic inflow.
  • Multi- service network
    • The Quality of Services is largely improved by using this technology of Multiprotocol Label Switching.
    • Service providers with the help of Multiprotocol Label Switching are able to decide before, the best way to control the certain types of traffic flow between the public and the private sectors.
  • Network resiliency with MPLS fast reroute
  • It is used not only for private sectors but also for all services.

Mechanism of Multiprotocol Label Switching:  

  • The Mechanism behind the Multiprotocol Label Switching is LSP and known as Label Switch Path.
  • It consists of two routers which are responsible for Label Switching
  • Label Switch Path is required for any forwarding of MPLS

MPLS router:

The various routers used in MPLS are

  • LER ( Label Edge Router ) / Ingress node
    • This is the first router which encapsulates a packet inside Label switch path (LSP).
    • This makes the initial path selection process
  • LSR ( Label Switching Router) / transit node
    • This is the router which is found in the center of Label Switch Path (LSP)
    • The main function is to Label Switch.
  • Egress node
    • This is the final router at the end of the Label switch path( LSP)
    • This is responsible for removing of the label in the final destination.

MPLS router roles:

The MPLS router roles are

  • P – Provider router
    • This is the backbone router which is used for label switching ( LBS)
    • There are used in large service provider like internet routes
  • PE – Provide edge router.
    • The role of Provide edge router is to cut the label which is assigned to present to the customer.
  • CE- Customer edge device.
    • This is a router where PE router connects.

MPLS for WAN Connectivity:

Advantages: –

  • The main advantage of Multiprotocol Label Switching over WAN connectivity is reliability and quality of serviced provided by MPLS.
  • 74% of organizations participated in Nemertes’ 2011-2012 Computing and Communications benchmark have successfully deployed MPLS.
  • WAN represents Wide area connectivity.

Comparison of Ethernet and MPLS for WAN connectivity:

  • MPLS can scale over thousands of sites whereas Ethernet scales only hundreds of sites
  • Multiprotocol Label Switching can connect many data from branches whereas Ethernet is not able to do so like Multi-protocol Label Switching
  • The advantage of the Ethernet over Multiprotocol Label Switching is mainly in the recovery of the system in any disaster. Multiprotocol Label Switching can connect any two things like voice and video.
  • MPLS has quality of service (QoS) options to enable preferential treatment of latency-sensitive traffic like VoIP whereas in Ethernet Network engineers can bypass QoS complexity by hooking switches directly to Ethernet pipe
  • However, the cost of MPLS is higher than that of Ethernet