Technique for providing constant bit rate (cbr) service over a time-slotted access channel

Abstract

According to specific embodiments of the invention, a technique is described for providing constant bit rate (CBR) service over shared access channels in a computer network. The technique of the present invention provides a plurality of linked lists of grant allocation elements at the head end of the network for implementing CBR service to requesting nodes on each shared access channel. Each grant allocation element corresponds to a respective unsolicited CBR grant allocated to a particular node on a selected channel. A CBR service request sent by a particular node to the head end is handled by an admission control engine within the head end. If admission control admits the CBR service request, it inserts one or more unsolicited grant allocation elements relating to the admitted request in at least one of the plurality of linked lists. Each linked list of grant allocation elements is used to generate a CBR portion of a respective, fixed size, grant allocation MAP message. Each grant allocation MAP message includes a first portion of N minislot allocations reserved primarily for CBR purposes, and a second portion of M minislot allocations reserved primarily for non-CBR purposes. Using the technique of the present invention voice traffic or other CBR applications may be supported on shared access channels with delay bound and zero jitter.