With MPLS, the first time a packet enters the network, it’s assigned to a specific
forwarding equivalence class (FEC), indicated by appending a short bit sequence
(the label) to the packet.
Each router in the network has a table indicating how to handle packets of a
specific FEC type, so once the packet has entered the network, routers don’t need
to perform header analysis.
MPLS network has the ability to handle packets with particular
characteristics (such as coming from particular ports or carrying traffic of
particular application types) in a consistent fashion.
Packets carrying real-time traffic, such as voice or video, can easily be mapped to
low-latency routes across the network — something that’s challenging with
How does MPLS work?
The beauty of MPLS is that it’s not tied to any underlying technology. It was
designed back in the days of ATM and frame relay as an overlay technique
designed to simplify and improve performance -- that’s the “multi-protocol” part.
ATM and frame relay are distant memories, but MPLS lives on in carrier
backbones and in enterprise networks.
The most common use cases are branch offices, campus networks, metro
Ethernet services and enterprises that need quality of service (QoS) for real-time
Benefits of MPLS
The benefits of MPLS are scalability, performance, better bandwidth
utilization, reduced network congestion and a better end-user experience.
MPLS itself does not provide encryption, but it is a virtual private network
and, as such, is partitioned off from the public Internet. Therefore, MPLS is
considered a secure transport mode.
It is not vulnerable to denial of service attacks, which might impact pure-IP-
Disadvantages of MPLS
MPLS must be purchased from a carrier and is far more expensive than
sending traffic over the public Internet.
As companies expand into new markets, they may find it difficult to find an
MPLS service provider who can deliver global coverage.
MPLS was designed in an era when branch offices sent traffic back to a
main headquarters or data center, not for today’s world where branch
office workers want direct access to the cloud.