Q-Logic 5800V ユーザーズマニュアル

2–Planning

Multiple Chassis Fabrics

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Connecting switches expands the number of available ports for devices. Each 
switch in the fabric is identified by a unique domain ID, and the fabric can 
automatically resolve domain ID conflicts. Because the Fibre Channel ports are 
self-configuring, you can connect QLogic 5800V Series switches in a wide variety 
of topologies. Transparent routing to a legacy fabric is also possible using 
TR_Ports.

You can connect up to six QLogic 5800V Series switches through the XPAK ports, 
thus preserving the SFP ports for devices. This is called stacking. QLogic 5800V 
Series switches divide the XPAK port buffer to balance traffic across the 
connection. The XPAK ports operate with any standard XPAK interface. You can 
also connect QLogic 5800V Series switches with other switches through the SFP 
ports in a wide variety of topologies. Consider your topology and cabling 
requirements.

When choosing a topology for a multiple chassis fabric, consider the proximity of 
your server and storage devices, and the performance requirements of your 
application. Storage applications such as video distribution, medical record 
storage and retrieval, or real-time data acquisition can have specific latency or 
bandwidth requirements.

The QLogic 5800V Series switch provides the lowest latency of any product in its 
class. However, the highest performance is achieved on Fibre Channel switches 
by keeping traffic within a single switch instead of relying on ISLs. Therefore, for 
optimal device performance, place devices on the same switch under the 
following conditions:



Heavy I/O traffic between specific server and storage devices.



Distinct speed mismatch between devices such as the following:



An 8-Gbps server and a slower 4-Gbps storage device



A high performance server and slow tape storage device

For specific information about latency, refer to 

.