Communication method for data communication based on point-to-point protocol

A communication method in a third communication apparatus of a first node located between a first communication apparatus of the first node and a second communication apparatus of a second node, the first communication apparatus and the second communication apparatus performing data communication based on PPP, the communication method comprising the steps of:

• intermediating a setting request packet from the second communication apparatus to the first communication apparatus;
• receiving a setting rejection packet or a setting negation packet from the first communication apparatus;
• producing a setting request packet according to the setting rejection packet or the setting negation packet;
• and
• transmitting the produced setting request packet to the first communication apparatus;
• wherein the third communication apparatus terminates a setting identification packet when the third communication apparatus receives the setting identification packet after intermediating the setting request packet from the second communication apparatus to the first communication apparatus and receiving the setting rejection packet or the setting negation packet from the first communication apparatus, and the third communication apparatus does not terminate a setting identification packet when the third communication apparatus receives the setting identification packet without receiving the setting rejection packet or the setting negation packet from the first communication apparatus after intermediating the setting request packet from the second communication apparatus to the first communication apparatus.