An explicit path is configured on the ingress of an MPLS TE tunnel. It defines the nodes through which the MPLS TE tunnel must pass or the nodes that are excluded from the MPLS TE tunnel.
An explicit path consists of a series of nodes. These nodes are arranged in sequence and form a vector path. An interface IP address on every node is used to identify the node on an explicit path. The loopback IP address of the egress node is usually used as the destination address of an explicit path.
Two adjacent nodes on an explicit path are connected in either of the following modes:
Strict: A hop is directly connected to its next hop.
Loose: Other nodes may exist between a hop and its next hop.
The strict and loose modes are used either separately or simultaneously.
TE tunnels are classified as intra-area tunnels and inter-area tunnels. In this situation, areas indicate OSPF and IS-IS areas, but not an autonomous system (AS) running the Border Gateway Protocol (BGP). OSPF areas are divided based on different area IDs while IS-IS areas are divided based on different levels.
Intra-area tunnel: is a TE tunnel in a single OSPF or IS-IS area. An intra-area tunnel can be established over a strict or loose explicit path.
Inter-area tunnel: is a TE tunnel traversing multiple OSPF or IS-IS areas. An explicit path must be used to establish an inter-area TE tunnel and an ABR or an Autonomous System Boundary Router (ASBR) must be included in the explicit path.
The explicit path in use can be updated.
The system view is displayed.
An explicit path is created and the explicit path view is displayed.
The next-hop address is specified for the explicit path.
The include parameter indicates that the tunnel does pass through a specified node; the exclude parameter indicates that the tunnel does not pass through a specified node.
A node is added to the explicit path.
The address of a node on an explicit path is changed.
A node is excluded from an explicit path.
Information about nodes on an explicit path is displayed.
The configurations are committed.