Multiprotocol Label Switching(MPLS)| MPLS in Indian Railways 

What is MPLS ?

 Multiprotocol Label Switching(MPLS) is a routing technique in telecommunications  networks that directs data from one node to the next based on short path labels rather than long network addresses, thus avoiding complex lookups in a routing table and speeding traffic flows.

 Based upon the committee reports and RDSO’s comments and recommendations, Railway Board has approved the Use of IP-MPLS technology/standards for telecommunication backbone for Indian Railways.

Present Routing Technique in Indian Railways 

Indian Railways is presently relying on legacy Synchronous Digital Hierarchy (SDH) network to meet Railway backbone telecommunication requirements. 

However off late, lot of applications like e-Office, IPAS, MMIS, FOIS etc. along with real time applications like Charting, COIS, CCTV & IPIS etc. are being deployed to improve the system of working. 

All the above applications require huge bandwidth for real time operation and monitoring.

 The existing SDH setup is a traditional network which has the limitations such as requirement of dedicated circuits for each site, wide spread outages in case of failure of head end terminal, low bandwidth per site, poor scalability and costly etc.

Introduction to IP MPLS Technology

MPLS has evolved to become the unifying packet transport technology with the addition of significant transport engineering capabilities. 

MPLS was created to improve packet performance and control traffic in the core of the Internet and private IP networks. While it continues to be widely used for that purpose, it has also been adapted for other uses. 

MPLS encapsulates data packets, adding packet headers that enable a variety of features; provides a rich set of control and monitoring functions; and is in wide use in business-oriented and performance critical services. 

MPLS offer network security features and enhanced quality ofservice (QoS).

MPLS delivers IP and Internet services enabling the core and edge network to act much like a TDM transport network but with a greater level of efficiency. 

Bandwidth capacity growth rates grow by triple digits each year with bandwidth-intensive applications like CCTV, Wi-Fi, mobile video, storages networking, and cloud data services continuing to drive growth.

pseudo wire technology

By employing MPLS pseudo wire, which is an encapsulation solution that can support native TDM, and packet traffic in the aggregation and access networks, it is possible to converge backhaul traffic without compromising service. 

Optimizing the use of network capacity is achieved by more granular increments of 10MB, 100 MB, 1GE, 10GE, 40 GE or even 100 GE.

An MPLS network is an integrated multi-access network that can support any or all wholesale, enterprise, residential, and mobile services.

 MPLS is used to transport Ethernet frames over a provider’s backbone network, with pseudo wires (PWE) acting as an emulated point-to-point connection over a packet switched network providing the interconnection of two nodes.

 An important feature of pseudo wire technology is that the service-specific functions are located only on the edge of the background network, while only MPLS label-switched paths (LSPs) are established in the core.

This  increases the scalability of the services and reduces the complexity of the core routers.

IP/MPLS has a great advantage in any-to-any connectivity environment an essential requirement for Railways.

Multiprotocol Label Switching(MPLS)

Multi-Protocol Label Switching (MPLS) is a packet forwarding Technology used on network Router and Switches allow for the virtualization of routing and forwarding table.

Why MPLS known as LAYER 2.5 Protocol?

 MPLS provides a Layer 2 transport method (SDH/SONET, Ethernet and TDM (E1/T1) etc.) for various protocol over packet switching network (PSN)

 i.e., it can be said that MPLS-TP operates between Layer 2 and Layer 3 in the OSI model → thus is often referred as” LAYER 2.5 Protocol” & IP – MPLS operates at Layer 2 & Layer 3.

label switching

MPLS uses the concept of label switching to forward the traffic based on the labels as opposed to the network addresses. 

Features of MPLS

There are many different features available under the MPLS  for the real time applications. 

MPLS overcomes many limitations of the traditional networks by allowing the shared hardware to be used by multiple independent clients. 

MPLS was the next evolution of networking after hub and spoke technology. 

Components of MPLS

MPLS has two main components which takes care of all functions of the MPLS connectivity. 

1. Label Switching Router (LSR)

2. Label Edge router (LER)

Label Switching Router (LSR) is the core router in the MPLS cloud which only does switching in the Label switching path (LSP- essentially a unidirectional tunnel between the pair of routers, routed across the MPLS cloud).

Label Edge router (LER) first encapsulate the packets inside the MPLS LSP and also make the initial path selection.

MPLS delivers IP and Internet Services enabling the core and edge network to act much like a TDM transport network but with a greater level of efficiency. Due to increased bandwidth capacity requirement for applications like CCTV, WIFI, Mobile Video, VOIP, Auto signaling, CTC, e-Office, IPAS, AIMS, ETCS – Level 2, IRATP, LTE etc., MPLS offers optimum bandwidth when compared with circuit switching methods.