John Henry Tuck

US Patent:

20050207410, Sep 22, 2005

Filed:

Dec 16, 2004

Appl. No.:

11/014546

Inventors:

Akshay Adhikari - Basking Ridge NJ, US
Amit Agarwal - Milpitas CA, US
Lorraine Denby - Berkeley Heights NJ, US
Russell Jones - San Jose CA, US
Rod Livingood - Cupertino CA, US
Jean Meloche - Madison NJ, US
Anupam Rai - San Jose CA, US
Wayne Sam - Verona NJ, US
John Tuck - Berkeley Heights NJ, US

International Classification:

H04L012/56

US Classification:

370389000

Abstract:

Techniques for determining a problem location or otherwise characterizing a network comprising a plurality of processing elements, including at least one processing element associated with performance of a packet encapsulation operation of an encapsulation protocol. The packet encapsulation operation is performed on a test packet to generate an encapsulated packet, the test packet having a time to live (TTL) value and an identifier. In conjunction with performance of the packet encapsulation operation, the TTL value and the identifier of the test packet are copied to a header of the encapsulated packet. The encapsulated packet is transmitted, and a determination is made as to whether a reply packet has been received responsive to transmission of the encapsulated packet. The reply packet, if any, is processed to obtain information utilizable in determining the problem location or otherwise characterizing the network. By way of example, these operations may be repeated, for subsequent test packets with increasing TTL values, until an amount of router hop information sufficient to determine the problem location is obtained.

US Patent:

20080205292, Aug 28, 2008

Filed:

Feb 26, 2007

Appl. No.:

11/678940

Inventors:

Lorraine Denby - Berkeley Heights NJ, US
Jean Meloche - Madison NJ, US
John R. Tuck - Berkeley Heights NJ, US

International Classification:

H04L 12/28

US Classification:

370254

Abstract:

Route asymmetry is detected in a network by running a route tracing program to trace routes between a first element of the network and a second element of the network. The route tracing program need be run at only a single network element, such as the first network element. Forward and reverse routes between the first and second network elements are identified as asymmetric if performance data from the route tracing program indicates a significant deviation from an expected monotonic characteristic as a function of time-to-live values of respective packets transmitted by the route tracing program.