Cisco MDS-9124 Troubleshooting Guide - Page 216

Trunking Overview Chapter 10 Troubleshooting PortChannels and Trunking Send documentation comments to [email protected] Trunking Overview Trunking, also known as VSAN trunking, is a feature specific to switches in the Cisco MDS 9000 Family. Trunking enables interconnected ports to transmit and receive frames in more than one VSAN, over the same physical link using extended ISL (EISL) frame format. Trunking configurations are only applicable to E ports. If trunk mode is enabled in an E port and that port becomes operational as a trunking E port, it is referred to as a TE port. The trunk-allowed VSANs configured for TE ports are used by the trunking protocol to determine the allowed-active VSANs in which frames can be received or transmitted. Trunking is a commonly used storage industry term. However, the Cisco SAN-OS software and switches in the Cisco MDS 9000 Family implement trunking and PortChannels as follows: • PortChannel enables several physical links to be combined into one aggregated logical link. • Trunking enables a link transmitting frames in the EISL format to carry (trunk) multiple VSAN traffic. When trunking is operational on an E port, that E port becomes a TE port. A TE port is specific to switches in the Cisco MDS 9000 Family. An industry standard E port can link to other vendor switches and is referred to as a nontrunking interface. Initial Troubleshooting Checklist Begin troubleshooting Portchannel and trunking issues by verifying that you have completed following actions first: Checklist Check off Use the show port-channel compatibility-parameters CLI command to determine PortChannel requirements. Ensure that one PortChannel is not connected to different sets of switches. PortChannels require point-to-point connections between the same set of switches. Verify that either side of a PortChannel is connected to the same number of interfaces. Verify that each interface is connected to the same type of interface on the other side. Verify that all required VSANS on a TE port are in the allowed-active VSAN list. Note Use the show running interface CLI command to view the interface configuration in Cisco SAN-OS Release 3.0(1) or later. The interface configuration as seen in the show running-config CLI command is no longer consolidated. Common Troubleshooting Tools in Fabric Manager The following Fabric Manager navigation paths may be useful in troubleshooting any issues with PortChannel and trunking: • Choose ISLs > PortChannel to access the PortChannel configuration. • Choose Switches > Interfaces > FC Logical and select the Trunk Config tab to access the trunking configuration. 10-2 Cisco MDS 9000 Family Troubleshooting Guide, Release 3.x OL-9285-05