MPLS TE
On traditional IP networks, routers select the shortest path as the route regardless of other factors such as bandwidth. Traffic on a path is not switched to other paths even if the path is congested. As a result, the shortest path first rule can cause severe problems on networks.
Traffic engineering (TE) monitors network traffic and the load of network components and then adjusts parameters such as traffic management, routing, and resource restraint parameters in real time. These adjustments help prevent network congestion caused by unbalanced traffic distribution.
TE can be implemented on a large-scale backbone network using a simple, scalable solution. MPLS, an overlay model, allows a virtual topology to be established over a physical topology and maps traffic to the virtual topology. MPLS can be integrated with TE to implement MPLS TE.
As shown in Figure 1, two paths are set up between LSR_1 and LSR_7: LSR_1 -> LSR_2 -> LSR_3 -> LSR_6 -> LSR_7 and LSR_1 -> LSR_2 -> LSR_4 -> LSR_5 -> LSR_6 -> LSR_7. Bandwidth of the first path is 30 Mbit/s, and bandwidth of the second path is 80 Mbit/s. TE allocates traffic based on bandwidth, preventing link congestion. For example, 30 Mbit/s and 50 Mbit/s services are running between LSR_1 and LSR_7. TE distributes the 30 Mbit/s traffic to the 30 Mbit/s path and the 50 Mbit/s traffic to the 80 Mbit/s path.
MPLS TE can reserve resources to ensure the quality of services during the establishment of LSPs.
The behavior of an LSP can be easily controlled based on the attributes of the LSP such as priority and bandwidth.
LSP establishment consumes few resources and does not affect other network services.
Backup path and fast reroute (FRR) protect network communication upon a failure of a link or a node.
These advantages make MPLS TE the optimal TE solution. MPLS TE allows service providers (SPs) to fully leverage existing network resources to provide diverse services, optimize network resources, and efficiently manage the network.