| 摘要 |
<p>PROBLEM TO BE SOLVED: To detect a routing loop and to change the operation of intermediate system (IS)/IS node by connecting a message through the connection of secondary selection to the target IS on the condition of sending the message back from a non-IS/IS area to the IS/IS area of an originating terminal. SOLUTION: NPDU from a node 1 to a node 7 is successively carried through nodes 2 and 3 to a node 4. When the node 4 carries the NPDU to a node 5, since the connection with the node 7 is cut off, the node 5 returns the NPDU to the node 4 and the node 4 sends it back to the node 3. The node 3 detects this link route is an internal RAP route connected to the non-IS/IS domain, and alternative routing is started by RAP. The node 3 carries the NPDU through the external RAP route to the node 2, the node 2 carries it to a node 6 and the node 6 carries the NPDU through the external RAP route to the node 7.</p> |
