Brocade Troubleshooting and Diagnostics Guide v6.1.0 (53-1000853-01, June 2008)

Fabric OS Troubleshooting and Diagnostics Guide 17
53-1000853-01
Chapter
3
Connections Issues
This chapter provides information on troubleshooting basic connectivity issues and the most
common procedures to use to diagnose and recover from basic connection problems.
In this chapter
•Port initialization and FCP auto discovery process . . . . . . . . . . . . . . . . . . . . 17
•Link issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
•Connection problems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19
•Link failures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
•Marginal links . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
•Device login issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
•Media-related issues. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
•Segmented fabrics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
Port initialization and FCP auto discovery process
The steps in the port initialization process represent a protocol used to discover the type of
connected device and establish the port type and port speed. The possible port types are as
follows:
• U_Port—Universal FC port. The base Fibre Channel port type and all unidentified, or uninitiated
ports are listed as U_Ports.
• L_/FL_Port—Fabric Loop port. Connects public loop devices.
• G_Port—Generic port. Acts as a transition port for non-loop fabric-capable devices.
• E_Port—Expansion port. Assigned to ISL links.
• F_Port—Fabric port. Assigned to fabric-capable devices.
• EX_Port—A type of E_Port. It connects a Fibre Channel router to an edge fabric. From the point
of view of a switch in an edge fabric, an EX_Port appears as a normal E_Port. It follows
applicable Fibre Channel standards as other E_Ports. However, the router terminates EX_Ports
rather than allowing different fabrics to merge as would happen on a switch with regular
E_Ports.
• VE_Port—A virtual E_Port. However, it terminates at the switch and does not propagate fabric
services or routing topology information from one edge fabric to another.
• VEX_Port—A virtual EX_Port. It connects a Fibre Channel router to an edge fabric. From the
point of view of a switch in an edge fabric, a VEX_Port appears as a normal VE_Port. It follows
the same Fibre Channel protocol as other VE_Ports. However, the router terminates VEX_Ports
rather than allowing different fabrics to merge as would happen on a switch with regular
VE_Ports.