Patent ID: 7633889
Filing Date: 2009-12-15
Classification: H04L

Abstract:
1. A carrier network in a virtual network system in which a plurality of user networks connected to said carrier network is constituted as a single virtual network by allocating an identical virtual network identifier to said plurality of user networks, comprising: an ingress communication node connected to at least a first user network of said plurality of user networks to receive a control frame transmitted from said first user network, and to attach a tag including said virtual network identifier, and to transmit said control frame attached with said tag to a transmission destination determined on the basis of said virtual network identifier: an egress communication node connected to at least a second user network of said plurality of user networks, to receive said control frame attached with said tag, which is to be transmitted to said second user network, to remove said tag from said control frame attached with said tag, and to transmit said control frame to said second user network; and a relay communication node to receive said control frame attached with said tag, transmitted from said ingress communication node, and to transfer said control frame to a transfer destination determined on the basis of said virtual network identifier included in said tag of said received control frame, wherein said ingress communication node copies header information of said control frame, modifies a destination address included in said copied header information from a destination address for said control frame to a destination address for broadcasting, and further attaches said copied header information including said modified destination address to said control frame as a new header, and said egress communication node further removes said attached new header from said control frame.