| 摘要 |
PURPOSE: A routing method on a network adopting a bi-directional line switching ring conception is provided to prevent a network management message from losing from a time point when a line is disconnected to a time point when nodes on every network share the same routing information by using a communication channel in the opposite direction to a bidirectional line switched ring(BLSR) concept. CONSTITUTION: After the second layer of a node A(21) and a node G(27) detects disconnection of the connection line in the second layer, they recognize that they are terminating points in the direction of a node A(21) - a node B(22) - a node C(23) - , ... , - a node G(27) and serve as the terminating point second layer. When a message is generated to be transmitted from a node B(22) to a node I(29), routing is performed as follows. First, the message is transmitted from the node B(22) to the node A(21) by the third layer according to the existing routing information. Thereafter, in the third layer of the node A(21), the message is transmitted to the second layer to go via the interval of the node A(21) - a node H(28) according to the existing routing information. At this time, the second layer of the node A(21) detects disconnection at the interval of the node A(21) - the node H(28), identifies that the message transmitted from the third layer is not a 'Hellow' packet for routing, and checks whether a source address of the message exists in a routing table of the second layer. If the source address exists, it signifies a message which has been converted into a second layer routing message and transmitted in the opposite direction due to the already disconnected line, the second layer of the node A(21) determines the message as a message having inaccessible network address and removes it. If no source address exists, the second layer of the node A(21) converts a message of the third layer into a routing message of the second layer and transmits it. Thereafter, the second layers of each node from the node B(22) to the node F(26) receive the second layer routing message, identify a destination address. If it's their own network address, they transmits the third layer data portion to the third layer, or otherwise, they transmits the third layer data portion in the opposite direction to the receiving direction. The second layer of the terminating point node G(27) receives the second layer routing message, stores a source address of the message in the second layer routing table and transmits the third layer data portion to the third layer. The third layer of the node G(27) transmits the message received from the second layer according to the existing routing information to the node F(26), and then the node F(26) transmits the message to the node I(29) connected to a public network according to the existing routing information. |
