Patent ID: 8027262
Filing Date: 2011-09-27
Classification: H04L

Abstract:
1. A method comprising: selecting an arbitrary node device belonging to a first virtual local area network to be detected from a certain network in which the first virtual local area network and a second virtual local area network are set up; sending a request packet from the arbitrary node device to each of its adjacent node devices that belong to the first virtual local area network, the request packet including a first count value indicating the number of communication hops across node devices, a media access control address of the arbitrary node device and a virtual local area network tag that identifies the first virtual local area network to be detected; sending from each of said adjacent node devices, upon receiving said request packet, said request packet in which said first count value is incremented or decremented to each of its adjacent node devices that belong to the first virtual local area network, excluding a sender of said request packet received, and a reply packet including said sender's media access control address, a media access control address of the node device that is a replying node device, the virtual local area network tag and a second count value copied from said first count value of said request packet received by said replying node device to a given return destination; collecting the reply packets including second count value entries, sender address entries and replying node address entries from said reply packets; creating a table of records including said second count value entries, said sender address entries, and said replying node address entries of each of collected packets; sorting the records in said table in ascending order of said second count value entries as a first key and further sorting the records in ascending order of said sender address entries as a second key; linking said sender node device and said replying node device in each record and plotting sender node devices with the same sender address as a convergence point; and determining topology of the first virtual local area network by analyzing the records in said table in order.