Patent ID: 8254394

Claim:
A method comprising: receiving a constant bit rate (CBR) service request at a cable modem network Head End, said CBR service request received from a node on a shared access channel, said CBR service request comprising a request to periodically transmit to said Head End a packet of p bytes; evaluating whether said CBR service request can be admitted; and in response to a determination that said CBR service request can be admitted, allocating a plurality of unsolicited grants for said node at predetermined, constant, periodic intervals, to thereby provide CBR service to said node, wherein said allocating includes providing a plurality of grant allocation MAP messages to said nodes at constant, periodic intervals, wherein the grant allocation MAP messages have a modified format, each grant allocation MAP message configured to have a first predetermined number N of minislot allocations reserved primarily for CBR purposes, and a second predetermined number M of minislot allocations reserved primarily for other purposes, wherein the minislot allocations reserved primarily for CBR purposes may be used for other purposes if not being used for CBR purposes, and wherein said grant allocation MAP messages provide information to nodes on said channel relating to ownership and types of minislots on said shared access channel which are to be used by said nodes to communicate with the Access Control System (ACS).