Multiplex communications – Wide area network – Packet switching
Patent
1994-01-24
1995-12-26
Chin, Wellington
Multiplex communications
Wide area network
Packet switching
370 951, 3701101, H04J 316, H04J 326, H04L 1256
Patent
active
054794072
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates generally to channel utilization in data and voice communication systems, and more particularly to optimizing channel utilization in Integrated Services Digital Networks (ISDN).
BACKGROUND ART
ISDN is a relatively newly developed and emerging field of telecommunications which integrates computer and communications technologies to provide, worldwide, a common, all-digital network. This is based, in part, on standardizing the structure of digital protocols developed by the International Telegraph and Telephone Consultative Committee (CCITT). Despite the implementation of multiple networks within national boundaries, from a user's point of view there is a single, uniformly accessible, worldwide network capable of handling a broad range of telephone, data and other conventional and enhanced services.
A complete description of the architecture of ISDN is beyond the scope of this specification. For details, and for an extensive bibliography of references of ISDN, see Stallings, ISDN, An Introduction, MacMillan Publishing Company, 1989.
An ISDN is structured by architecture closely following the OSI Seven Layer Reference Model. Within the framework of ISDN, the network provides services and the user accesses the services through the user-network interface. A "channel" represents a specified portion of the information carrying capacity of an interface. Channels are classified by two types, Basic Rate ISDN (BRI) and Primary Rate ISDN (PRI). BRI delivers two B-channels, each having a capacity of 64 Kbps, capable of transmitting voice and data simultaneously. A 16Kbps D-channel transmits call control messages and user packet data. PRI provides twenty three B-channels of 64 Kbps capacity each for carrying voice, circuit switched data or packet data. The D-channel is a 64Kbps signaling channel. The B and D channels are logically multiplexed together at Layer 1 of the OSI Reference Model.
With reference to FIG. 1, the conventional ISDN interfaces are depicted. At the customer premises, an "intelligent" device, such as a digital PBX terminal controller or Local Area Network (LAN), can be connected to an ISDN terminal TE, such as a voice or data terminal, which is connected to a Network Termination (NT1). Non-ISDN terminals TE may be connected to a Network Termination (NT2) [over the RS-232 Interface] and a Terminal Adapter TA. The NT2 in turn is connected over an "S/T-Interface", which is a four-wire bus, to a termination NT1 that performs functions such as signal conversion and maintenance of the electrical characteristics of the loop.
At the local loop, a two-wire bus, termed the "U-Interface", or "Loop", interconnects NT1 and a Loop Termination (LT) at the central office. Finally, the "U-Interface" is a bus between the local loop at the carrier end and exchange switching equipment. Details of this architecture are provided in ISDN: An Overview, Data Pro Research, Concepts & Technologies, MT 20-365; pp 101-110, published by McGraw Hill Incorporated (December 1988).
ISDN can be used to service the needs both of public data telephony and private networks. In general, access to public telephone is performed as shown in FIG. 2(a). An initiating host H first issues dialing commands to the public network to set up a connection with the destination host H, and then uses the connection to communicate with the destination host. The connection either is circuit switched or packet switched. Data communication in private networks incorporates routers, generically called Interface Message Processors (IMPs), which may also be used as hosts. In FIG. 3(a), a host A communicating with host C will take an appropriate route through an IMP interface.
To establish communications between a host and the ISDN, a gateway operating at the upper layers of the OSI reference model accomplishes gateway functions, translating protocols used on dissimilar networks. An ISDN gateway, designated by GW in FIG. 1, will operate entirely in the digital domain, carrying out all necessary protocol conversion b
REFERENCES:
patent: 4556972 (1985-12-01), Chan et al.
patent: 4677616 (1987-06-01), Franklin
patent: 4799219 (1989-01-01), Calvignac et al.
patent: 4993024 (1991-02-01), Quinguis et al.
patent: 5012469 (1991-04-01), Sardana
patent: 5165021 (1992-11-01), Wu et al.
Cummings Paul
Gagliardi Ugo G.
Hsu Meichun
Ko Cheng-Hsu
LandOfFree
Channel utilization method and system for ISDN does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Channel utilization method and system for ISDN, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Channel utilization method and system for ISDN will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1374324