Orhan Ergun No Comments

Benefits of MPLS, Why MPLS is used on today networks and the Advantages of MPLS will be explained in this post.

As an Encapsulation and VPN mechanism, MPLS brings many benefits to the IP networks. In this article most of them will be explained and design examples will be shared by referring more detailed articles on the website as well.

Below list shows the benefits of MPLS. Although this may not be the full list, comment section always open for your comment and questions.

 

  • Faster packet processing with MPLS compare to IP

Initially MPLS invented to provide faster packet processing compare to IP based lookup. With MPLS instead of doing IP destination based lookup, label switching operation is done. Smaller MPLS header compare to IP header is processed and provides performance benefit. Although today nobody enable MPLS for this reason, this was the initial reason for MPLS as I stated above.

 

Without MPLS, if BGP is running on the network, it needs to run on every device on the path. MPLS removed this need, less protocol means, simpler network and easier maintenance.

 

  • Hiding service specific information (customer prefixes, etc.) from the core of the network

When MPLS is used on the network, only the edge devices has to keep the customer specific information such as MAC address, Vlan number, IP address and so on. Core of the network only provides reachability between the edges. I wrote an article ‘ Edge devices are the brains of the network ‘ for networkcomputing earlier. Take a look at this to understand which services and capabilities are provided by the edges and the role of the core devices in the IP and MPLS networks.

 

  •  More scalable network

Not having service specific information on the core of the network provides better scalability. CPU and Memory point of view as well as dealing with the routing protocol updates, link state changes and many other problems abstract from the core of the network by using MPLS.

 

  • MPLS VPNs -MPLS  Layer 2 and Layer 3 VPNs

Probably the most important reason and main benefit of MPLS is MPLS VPNs. MPLS as you might know allows to create Point-to-point, point-to-multipoint and multipoint-to-multipoint type of MPLS layer 2 VPN and MPLS layer 3 VPNs.

By using BGP, LDP and/or RSVP protocols, VPNs can be created. There are tens of articles on MPLS VPNs on the website.

 

  • Traffic Engineering

MPLS with the RSVP-TE provides traffic engineering capability which allows better capacity usage and guaranteed SLA for the desired service. MPLS Traffic Engineering are explained with the many articles on the website in detail.

 

  • Fast Reroute

With RSVP-TE, MPLS provides MPLS Traffic Engineering Fast Reroute Link and Node Protection. RSVP-TE is one option but with LDP, LFA and Remote LFA can be setup if RSVP-TE is not used in the network. MPLS Traffic Engineering Fast Reroute can protected the important service in any kind of topology and provides generally less than a 50msec protection.

On the other hand, IP FRR mechanisms require highly meshed topology to provide full coverage in the case of failures.

When LDP is used without RSVP-TE, solution is also called as IP Fast Reroute. There was CR-LDP (Constrained based) draft but since it is deprecated I don’t mention here.

MPLS doesn’t bring security by default. If security is needed then IPSEC should run on top of that. Best IPSEC solution for the MPLS VPNs is GETVPN since it provides excellent scalability.
MPLS is used mainly for the Wide Area Network but there are implementation for Datacenter Interconnect, Datacenter Multi segmentation as well.

Today with PCE (Path Computation Element), MPLS is considered to be used in SDN (Software Defined Networking) for network programmability, multi area and multi domain traffic engineering and automation purposes as well. This will be the separate article topic.

 
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