Multiplex communications – Communication techniques for information carried in plural... – Adaptive
Reexamination Certificate
1997-11-26
2001-01-23
Ngo, Ricky (Department: 2731)
Multiplex communications
Communication techniques for information carried in plural...
Adaptive
C370S401000
Reexamination Certificate
active
06178180
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a communications adapter, and more particularly to such an adapter which can be used both for time-division multiplexed signals in an ISDN environment and for digital packets in an ATM environment.
2. Background Information
In North America, the PRI (Primary Rate Interface) version of ISDN (Integrated Services Digital Network) service provides 23 B (Bearer) channels at 64 kbps and a single D channel, also at 64 kbps. In Europe, this version provides 30 B channels and a single D channel. User information is carried on the B channels, with the D channel being used for call control. In North America, this service is provided along a T
1
transmission line, while in Europe, this service is provided along an E
1
transmission line. The various channels are combined for transmission along a single wire by means of TDM (Time Division Multiplexing), with the channels being given fixed-length frames, or segments of transmission time, in a sequential fashion. Using ISDN, a computing system can place and receive calls over the public switched telephone network to a different client device on each channel, or to another device configured to transmit and receive ISDN data.
Asynchronous Transfer Mode (ATM) service uses a packet-mode technology in which information is transmitted in cells having a fixed length of 53 bytes. Each cell includes a header having a length of 5 bytes, including information needed to send the cell data to the correct location, and a payload of 48 bytes, including the data being transmitted. This ATM technology is used extensively with fiber optical transmission lines to form LANs (Local Area Networks) and backbones tying conventional LANs together. ATM service may also be provided along a T
1
data transmission line in North America and along an E
1
data transmission line in Europe.
Since many organizations have a need to communicate both with a LAN using ATM technology and with one or more remote locations using ISDN service over the public switched telephone network, what is needed is a communications adapter which can be configured to operate with either or both ATM and ISDN data.
Description of the Prior Art
U.S. Pat. No. 5,572,695 describes a digital signal processing system including first and second logical memory mapping units coupled to first and second digital processors, respectively, and to a data storage unit. The system further includes first and second mapping registers for containing first and second address mapping information coupled to the first and second digital processors, respectively. The first and second mapping units are operative to receive (i) first and second logical addresses generated by the first and second digital processors respectively and (ii) first and second address mapping information respectively, and generate first and second physical addresses such that each of the digital processors can independently access any of a plurality of memory locations within the data storage unit.
In a first mode of operation, each DSP shares only the first memory page (e.g. 64K words) of DRAM (data RAM) memory, with the first and second logical lookup addresses being independently mapped to the first lookup region. In a second mode of operation, each DSP can share the first and second memory pages (e.g. 128K words of in the DRAM, with the first and second logical lookup addresses being independently mapped to either one of the first and second lookup regions. In a third mode of operation, each DSP has its own dedicated memory page (e.g. 32K words), with the first logical lookup addresses being mapped into the first lookup area of the DRAM. In the first and second of these modes of operation, the first and second DSPs can both share the same channel area when necessary, allowing one DSP to perform transmit functions while the other DSP performs receive functions on the same channel.
U.S. Pat. No. 5,602,841 describes an efficient point-to-point and multipoints routing system and method for programmable data communication adapters in packet switching modes of high-speed networks. The general principles of efficiency are, first, that data packets are never copied during their routing through the adapter, with only packet pointers being copied for each destination, second, that no overhead is generated by the multi-points routing in the real-time procedures, third, third, that each output is processed independently by means of interrupts, and, fourth, that the release of the resources is entirely realized on a non-priority mode. The system is described as having an adapter including a receive adapter with a receive specific purpose processor and a transmit adapter having a transmit specific purpose processor.
Again, what is needed is a communications adapter which can operate with both ATM and ISDN data.
SUMMARY OF THE INVENTION
It is therefor an objective of the present invention to provide a communications adapter which can be used for either ISDN or ATM data.
It is another objective of the present invention to provide a communications adapter attaching to two transmission lines to process ISDN data transmitted and received along a first such transmission line simultaneously with ATM data transmitted and received along the second such transmission line.
Thus, according to a first aspect of the present invention, there is provided a communications adapter including a first connector for electrically connecting a first transmission line, a first network interface extending into the communications adapter from the first connector, a data bus, and first signal processing means electrically connecting the data bus with the first network interface. The first signal processing means is operable in an ISDN mode, converting data from the data bus for transmission in an ISDN format from the communications adapter through the first connector and converting data received by the communications adapter through the first connector in the ISDN format into an encoded format for transmission from the first processing means along the data bus. The first signal processing means is additionally operable in an ATM mode, converting encoded data from the data bus for transmission in an ATM format from the communications adapter through the first connector and converting data received by the communications adapter through the first connector in the ATM format into an encoded format for transmission from the first processing means along the data bus.
According to a second aspect of the present invention, the communications adapter described above additionally includes a second connector for electrically connecting a second transmission line, a second network interface extending into the communications adapter from the second connector, a data bus, and second signal processing means electrically connecting the data bus with the second network interface. The second signal processing means has capabilities similar to those of the first signal processing means. The first and second signal processing means are preferably independently programmably configurable for operation in the ISDN mode or in the ATM mode. Each of the signal processing means preferably includes a pair of digital processors, a parallel bus, and a serial to parallel interface.
REFERENCES:
patent: 5375118 (1994-12-01), Rao et al.
patent: 5572695 (1996-11-01), Andrews et al.
patent: 5602841 (1997-02-01), Lebizay et al.
patent: 5809022 (1998-09-01), Byers et al.
patent: 5867496 (1999-02-01), Peres et al.
patent: 5930250 (1999-07-01), Klok et al.
patent: 5959996 (1999-09-01), Byers
patent: 5968158 (1999-10-01), Andrews et al.
IBM Technical Disclosure Bulletin, Buffer Management for Primary Rate Communications Adapters, vol. 34, No. 8, Jan. 1992, pp. 313-316.
IBM Technical Disclosure Bulletin, Foreground State Machine Facility for Multi-Channel Data Link Communications, vol. 35, No. 4A, pp. 266-271.
Eng Robert Chih-Tsin
Graves Kevin Lee
Parikh Himanshu Chandrakant
Sinibaldi John Claude
Davidge Ronald V.
International Business Machines Corp.
Ngo Ricky
Tomlin Richard A.
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