The following are the configuration steps at the LSP and LSP path levels.
The operator configures the CT in which the LSP belongs by configuring the class-type ct-number command at the LSP level and, or the path level. The path level value overrides the LSP level value. By default, an LSP belongs to CT0.
Only one CT per LSP path is allowed per RFC 4124, Protocol Extensions for Support of Diffserv-aware MPLS Traffic Engineering. A multi-class LSP path is achieved through mapping multiple system Forwarding Classes to a CT.
The signaled CT of a dynamic bypass must always be CT0 regardless of the CT of the primary LSP path. The setup and hold priorities must be set to default values, for example, 7 and 0 respectively. This assumes that the operator configured a couple of TE classes, one which combines CT0 and a priority of 7 and the other which combines CT0 and a priority of 0. If not, the bypass LSP is not signaled and goes into the down state.
The operator cannot configure the CT, setup priority, and holding priority of a manual bypass. They are always signaled with CT0 and the default setup and holding priorities.
The signaled CT, setup priority and holding priority of a detour LSP matches those of the primary LSP path it is associated with.
The operator can also configure the setup and holding priorities for each LSP path.
An LSP which does not have the CT explicitly configured behaves like a CT0 LSP when Diff-Serv is enabled.
If the operator configured a combination of a CT and a setup priority and, or a combination of a CT and a holding priority for an LSP path that are not supported by the user-defined TE classes, the LSP path is kept in a down state and error code is shown within the show command output for the LSP path.