Patent ID: 6856593

Claim:
A communication system for establishing a connection via a plurality of relay apparatuses between an end system of a communicating source and an end system of a communicating destination and communicating data, wherein each of said relay apparatuses comprises: a connection negative response unit which, when an error of a next relay destination is detected at the time of reception of a connection establishment request, refuses the connection establishment request and transmits a negative response to a relay source; and a negative response relay unit which, when said negative response is received from the relay destination, transmits the received negative response to the relay source, and said end system of the communicating source has a connection establishment requesting unit which, when said negative response is received from the relay destination after said connection establishment request is transmitted, issues again the connection establishment request in which another relay destination has been selected without notifying an application of a failure of the connection establishment and establishes a connection to the communicating destination end system by another path.