Advanced bridge/router local area network modem node

United States Patent m

Parameswaran Nair et al.

US005724356A [ii] Patent Number: 5,724,356 [45] Date of Patent: Mar. 3, 1998

[54] ADVANCED BRIDGE/ROUTER LOCAL AREA NETWORK MODEM NODE

[75] Inventors: Vidyasagaran Parameswaran Nair;

Damodar Bhat. both of Bangalore,
India; Hung S. Ngo. Spring Lake Park,
Minn.; Narasimhan Sundarraajan,

Bangalore. India

[73] Assignee: Multi-Tech Systems, Inc., Mounds View, Minn.

[21] Appl. No.: 431,715

[22] Filed: Apr. 28, 1995

[51] IntCl.6 H04J3/02

[52] U.S. CI 370/401; 370/402; 370/465;

375/222

[58] Field of Search 370/85.13, 32.1,

370/94.1, 95.1, 60, 401, 402. 403, 289, 389, 394, 422, 437, 465; 375/222, 223;

379/93, 88

[56] References Cited

U.S. PATENT DOCUMENTS

4,406,004 9/1983 Hall et al 370/15

4,610,022 9/1986 Kitayamaetal 381/36

4,625,081 11/1986 Lotito et al 379/88

4,794,595 12/1988 Ohyama 370/110.1

4,866,704 9/1989 Bergman 370/858.5

4,873,715 10/1989 Shibata 379/93

4,901,312 2/1990 Hui et al 370/85.14

4,996,707 2/1991 O'Malley et al 379/94

5,202,899 4/1993 Walsh 375/8

5,220,560 6/1993 Ogasawara 379/94

5,355,365 10/1994 Bhatetal 370/85.13

5,390,239 2/1995 Morris et al 375/222

5,406557 4/1995 Baudoin 370/85.13

5,416,776 5/1995 Panzarella et al 379/93

5,452,289 9/1995 Shannaetal 370/32.1

5,477347 12/1995 Sugiyama 370/94.1

5,479,407 12/1995 Ko et al 370/94.1

5,550,816 8/1996 Hardwicketal 370/60

FOREIGN PATENT DOCUMENTS 3504064 8/1986 Germany .

3630469 3/1988 Germany.

3409532 4/1989 Germany.

193489 7/1990 Japan.

257748 10/1990 Japan.

OTHER PUBLICATIONS

S. Apiki et al.. "Network Modems Dial In, Dial Out, and Router Packets", Byte, 12, pp. 269-270, 272, 274 (1992). J.T. Johnson, "Lan Modems: The Missing Link for Remote Connectivity", Data Communications, pp. 101-104, 106, 'Mar. 1993.

"Video Calls Use Basic Phone Lines", Mitch Radcliffe,
MacWeek, (Aug. 3, 1992).

"Radish System Lets Phones Users Send Voice, Data Simul-
taneously", PC Week, 9, 19, p. 53, (May 11, 1992).
"Don't Just Tell Them, Show Them!", Glenn A. Pierce, Jr.,
Automation, (Aug. 1990).

"Mitsubishi Still Color Picture TV Phone", Techno Japan, 23, 6, (Jun. 1990).

"The Photophone", (Product Brochure) GTE (Feb. 15. 1990).

"Wrist TVs Still Fiction, but Police Videophones Take Hold", Ray Smith, TE&M, (Dec. 15, 1987).

(List continued on next page.)

Primary Examiner—Douglas W. Olms
Assistant Examiner—Shick Horn

Attorney, Agent, or Firm—Schwegman, Lundberg,
Woessner & Kluth, P.A.

[57] ABSTRACT

An intelligent LAN modem node is used in a bridge system which provides transparent internetwork communications over a plurality of channels. The LAN modem node is protocol independent and has a packet load distribution system which shares packet traffic across the channels using optional user-defined channel preferences. The LAN modem nodes used in the bridge system provides compression for increasing bridge transmission speed. The bridge system provides a filtering system to control access over the bridge and restrict unnecessary bridge traffic. Additionally, the bridge system provides automatic redial in the event modem communications are lost.

13 Claims, 81 Drawing Sheets

OTHER PUBLICATIONS

"Audiographic Terminal". M. Laube, Electrical Communication, 60, 1, (1986).

"Comparison of Coding Schemes for Telewriting Systems", Tominaga et al., JCCC, (1986).

"Simultaneous Transmission of Voice and Handwriting Signals: Sketchphone System", Kishimoto et al., IEEE, (1981).

'Telewriting Terminal Equipment" (Recommendation T.150) CCTTT, (1988).

"A Family of 2-Wire, Duplex Modems Operating at Data
Signalling Rates . . . ", Facsimile Recommendation V.32
CCITT, (1988).

"* * * Picfon Card Brochure", Specom Technologies Corp.,
(Published Prior to Applicant's Invention).
'Ten Telephone Brochure", Shimadzu, (Published Prior to
Applicant's Invention).

"Telewriter Product Description", Optel Communications,
Inc., (Published Prior to Applicant's Invention).
"Videowriter '91 Product Description", Optel Communica-
tions, Inc., (1991).