Diff-Serv traffic engineering (TE) provides the ability to manage bandwidth on a per-TE class basis as per RFC 4124. In the base traffic engineering, LER computes LSP paths based on available BW of links on the path. Diff-Serv TE adds ability to perform this on a per-TE class basis.
A TE class is a combination of Class Type and LSP priority. A Class Type is mapped to one or more system Forwarding Classes using a configuration profile. The operator sets different limits for admission control of LSPs in each TE class over each TE link. Eight TE classes are supported. Admission control of LSP paths bandwidth reservation is performed using the Maximum Allocation Bandwidth Constraint Model as per RFC 4125.