Crosslink Errors PDF Troubleshooting Guide

Crosslink Errors 13 February 2024 16:19 Diagnostic messages are sent to each FTE interface port. One part of the diagnostic message designates the interface port of the message which is whether the message is transmitted on the Yellow tree or the Green tree. A question that arises in this case i...

Crosslink Errors 13 February 2024 16:19 Diagnostic messages are sent to each FTE interface port. One part of the diagnostic message designates the interface port of the message which is whether the message is transmitted on the Yellow tree or the Green tree. A question that arises in this case is how is the interface port connection designated as Yellow or Green? The answer is the MAC address. It is used to designate the interface port connection. The interface port connection with the lower MAC address is usually designated as the Yellow connection whereas the port connection with the higher MAC address is designated as the Green interface. Note that the binding order must remain consistent to maintain the correct interface port designation for the messages. When there is a crossover cable connected between switches, Yellow and Green diagnostic messages are transmitted on both FTE trees. As you can see, the FTE Status Display shows that all connections are operational and that diagnostic messages are traversing throughout the network. In certain cases, if FTE trees are isolated from each other, diagnostic messages must also be isolated. This means that messages designated as Yellow must be seen on the Yellow tree only and messages designated as Green must be seen on the Green tree only. To achieve isolation in FTE trees, you need to remove the Crossover cable. What should happen on removing the crossover cable? In an ideal scenario, Yellow diagnostic messages must not be seen on the FTE Green tree and vice versa. But as you can see on the screen, even after removing the crossover cable and isolating the trees, Yellow diagnostic messages are seen on the Green tree or green diagnostic messages are seen on the Yellow tree. This is what constitutes a crosslink error. This is also seen in the FTE Status display, where after removing the crossover cable, status for paths A to B and B to A should go red. Due to the crosslink error, these paths are healthy and displayed in green. EPKS L1 Page 1 green. Possible Causes? Cables are crossed at the node A possible cause of the Crosslink error could be that the cables are cross-connected at the node. This means that the Cable with the Yellow boot is connected to the switch in the Yellow tree, but it is connected to the second port. In addition, the cable with the Green boot is connected to the switch in the Green tree, but it is connected to first port. Cables are crossed at the switches The second possibility could be that the cables are crossed at the switch. This means that the connection for the first port that is the cable with Yellow boot is connected to the switch in the Green tree. Whereas, the connection for the second port that is the cable with the Green boot is connected to the switch in the Yellow tree. Both FTE cables are connected to the same tree A crosslink error occurs because both FTE cables are connected to the same tree. This means that the cables with the Yellow boot and the Green boot are connected to the same switch. FTE network topology does not follow configuration rules Another cause for the crosslink error could be that the FTE network topology does not follow proper configuration rules. Any condition that creates network path loops, such as: The FTE network consisting of more than one crossover cable. Multiple connections to an external network or switches not connection in a tree hierarchy. EPKS L1 Page 2