Mpls vpn what is

It is a suite of different MPLS-based VPN technologies that provide the ability to utilize multiple protocols and technologies for creating and managing communications in a VPN environment. The question is — public internet is already very fast and has a near-ubiquitous global reach, why businesses still need an MPLS based VPN?

The apt answer to this question is that public internet only focuses on the transport of data packets with no consideration of QoS Quality of Service , uptime guarantee, and offers limited capabilities.

Though for the past few years, public internet has worked fine for e-mail and file transfers, there is a need for an advanced protocol that can support converged applications and multimedia traffic.

Another reason is video being the fastest-growing application these days, bringing immense traffic for profitable business growth. A single commercial internet connection often comes up with capacity limitations.

If enterprises purchase and manage multiple connections to achieve the desired capacity during peak hours, they will eventually add costs and complexity to the equation. They also need to achieve low latency required for real-time communications to work properly.

Due to this flexibility, many suppliers have developed their network switches suited for MPLS platform. VPN and MPLS differ from each other not only in the above mentioned aspects but also at cost, performance, application, etc. For example, If your company is running critical, real-time applications across the network such as voice, video or remote desktop , MPLS is a perfect solution. Instead, it uses MPLS labels. Let us understand how MPLS works using an example. The figure depicts an IPv4 network topology with four routers.

Routers choose an MPLS label for every route on the network. For instance, routers R1, R2, R3 and R4 have labels , , and for the network Note: The label field is 20 bits in length. However, the first 16 label values i. Routers then exchange the labels they have chosen for every route in the network with their neighbouring routers.

Using the label advertisements from neighbouring routers, each router builds an MPLS forwarding table. Now the routers are ready to use labels to forward packets. The interfaces belong to the routing tables, and the routing protocol parameters control the information in the routing tables. A VRF instance consists of one or more routing tables, a derived forwarding table, the interfaces that use the forwarding table, and the policies and routing protocols that determine what goes into the forwarding table.

Because each instance is configured for a particular VPN, each VPN has separate tables, rules, and policies that control its operation. Because a typical transit network is configured to handle more than one VPN, the provider routers are likely to have multiple VRF instances configured.

As a result, depending on the origin of the traffic and any filtering rules applied to the traffic, the BGP routing tables can contain multiple routes for a particular destination address.

A route distinguisher is a locally unique number that identifies all route information for a particular VPN. Unique numeric identifiers allow BGP to distinguish between routes that are otherwise identical. Each routing instance that you configure on a PE router must have a unique route distinguisher.