LSP are parameters attributed to the initial setup and duration of an LSP. The values are used to provide a mechanism to allow certain more preferred LSPs to signal themselves or preempt other less preferred LSPs. There are two values used for this purpose, the setup value and the hold value; both values range from 0 to 7 with 0 being considered the stronger, more preferred value.
The setup value is used when LSPs are initally signalling, the LSPs with lower values are always signalled first. The hold value is used to protect an LSP from being preempted by a new LSP that may require signalling and resources from the network.