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US006185215B1
(12) United States Patent ao) Patent No.: us 6,185,215 Bi
Aho (45) Date of Patent: Feb. 6,2001
(54) COMBINED ROUTER, ATM, WAN AND/OR LAN SWITCH (CRAWLS) CUT THROUGH AND METHOD OF USE
(75) Inventor: Michael E. Aho, Rochester, MN (US)
(73) Assignee: International Business Machines Corporation, Armonk, NY (US)
( * ) Notice: Under 35 U.S.C. 154(b), the term of this patent shall be extended for 0 days.
(21) Appl. No.: 08/732,552
(22) Filed: Oct. 15, 1996
(51) Int. CI.7 H04L 12/28; H04L 12/56;
H04J 3/16; G01R 31/08
(52) U.S. CI 370/402; 370/465; 370/218
(58) Field of Search 370/428, 429,
370/465, 217, 218, 225, 228, 401, 402, 397, 352, 399
(56) References Cited
U.S. PATENT DOCUMENTS
5,452,293 9/1995 Wilkinson et al 370/54
5,452,296 9/1995 Shimizu 370/60.1
5,453,979 9/1995 Shibler et al 370/60.1
5,500,860 * 3/1996 Perlman et al 370/401
5,521,913 * 5/1996 Gridley 370/389
OTHER PUBLICATIONS
ATM Year 96, May 6-9, 1996, San Jose, CA, Session: IP/ATM Protocol Research, Speaker: Mr. Tom Lyon, Founder & Chief Technical Officer, Ipsilon Networks, Inc., pp. 1-10.
A cut through is provided in a combined router/switch in a data processing system network by having the router store and forward a first portion of a data flow from a source to a destination. The router determines whether the data flow is suitable for cut through. If found suitable, the router sends a redirect protocol to the source, directing the source to use a different destination address for all or part of the remainder of the data flow. The portion of the data flow having new destination address is then cut through the combined router/ switch by the switch. If the cut through has a failure, responsibility for the data flow delivery returns to the router. If the destination of a cut through data flow is unavailable, the frames are stored by the switch and forwarded when the destination is available.
19 Claims, 14 Drawing Sheets
