A Network Logical Connection
One other item of interest in Figure 1 is the LSP123 entity, which is a logical connection (called a label switched path) and is similar in a way to a telephone call—it is explicitly set up, data travels over it, and at some point in the future might be deleted or updated. LSP123 represents a forwarding path between routers R2, R3, R4, and R5, and this path is employed to carry data traffic from R2 to R5. The reason why such connections are used is to allow the network to be carved up in a democratic and controllable fashion.