C H A P T E R 10 Troubleshooting Portchannels And Trunking; Trunking Overview; Initial Troubleshooting Checklist; Common Troubleshooting Tools In Fabric Manager - Cisco 9134 - MDS Multilayer Fabric Switch Troubleshooting Manual

Trunking Overview

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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:
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Initial Troubleshooting Checklist

Begin troubleshooting Portchannel and trunking issues by verifying that you have completed following
actions first:
Checklist
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.
Use the show running interface CLI command to view the interface configuration in Cisco SAN-OS
Note
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:
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Cisco MDS 9000 Family Troubleshooting Guide, Release 3.x
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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.
Choose ISLs > PortChannel to access the PortChannel configuration.
Choose Switches > Interfaces > FC Logical and select the Trunk Config tab to access the trunking
configuration.
Chapter 10 Troubleshooting PortChannels and Trunking
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