Abstract: A router in a network comprises an interface system for receiving packets and has a plurality of channels and a plurality of framing service engines. The router is configured to assign the channels to individual framing service engines for framing services. The router has a channel manager for performing the assignments, and the channel manager is configured to receive and use data about the framing service engines. The router further comprises a framing memory for buffering communication between the interface system and the plurality of framing service engines. At least one framing service engine is configured to frame packets and at least one framing service engine is configured to deframe packets, and the framing service engines may be configured to operate on AHDLC packets. The router can be used with an interface system that comprises a plurality of network interfaces terminating a plurality of point to point links.

Abstract: An apparatus and method for extending the range of a digital data network by enhancing skew control. The apparatus is a circuit for use in a network interface unit. The apparatus measures the distance of the network interface unit from the head-end retransmission unit of the network by transmitting a series of signal packets on the network and counting the time it takes for the packets to be received back at the interface unit. All transmissions on the network take place with reference to a timing mark transmitted by the head-end unit at a regular interval. The apparatus sends the first in the series of signal packets at a pre-determined pre-skew interval before the timing mark. The apparatus counts the number of clock cycles after the timing mark before the signal packet is received back at the network interface unit.