I always think the term MPLS application is a useful concept because it’s similar to other, more familiar applications, such as word processing software, email, etc. Figure 5 illustrates the concept where an end user employs a suite of applications to fulfill his/her needs.
Figure 5 The use of applications.
It’s a similar idea with MPLS: It can be used to accommodate certain needs, such as the creation of a VPN. An MPLS application such as a VPN is the combination of many entities:
- Application-level entities—virtual routing forwarding objects
- Routing protocols
- Signaling protocols
- Traffic engineering
The combination of these entities then provides an application function, in this case a VPN. Other MPLS applications include pseudowires for the transport of layer traffic through an MPLS network.