Patent ID: 8750163

Claim:
A communication system comprising: a path management server that configures forwarding path information by arranging identifiers for identifying communication interfaces provided in respective forwarding nodes in a forwarding path of a data transfer network or configures the forwarding path information by arranging identifiers for links extending between said respective forwarding nodes and neighboring nodes thereof; and a forwarding node that performs a packet forwarding processing in accordance with said forwarding path information, with regard to a packet to which is added a header containing said forwarding path information, wherein, among said forwarding nodes, a boundary forwarding node positioned at a boundary with an external network comprises a header operation unit that performs addition of a second header containing said forwarding path information to a packet received from said external network, or performs removal of a header containing said forwarding path information from a packet transmitted to said external network, and wherein said boundary forwarding node further comprises a cache management unit that holds information included in said second header, when said second header is removed, and a third header formed using said held information is assigned to a packet in a reverse direction transmitted to a source of said packet from which said second header was removed.