Configuring Oversubscription Ratio Restrictions - HP Cisco MDS 9216 - Fabric Switch Configuration Manual

Chapter 22 Configuring Generation 2 Switches and Modules
S e n d d o c u m e n t a t i o n c o m m e n t s t o m d s f e e d b a c k - d o c @ c i s c o . c o m
Click the Apply Changes icon.
Step 5
.
Changing port speed and rate mode disrupts traffic on the port.
Caution

Configuring Oversubscription Ratio Restrictions

The 48-port and 24-port 4-Gbps Fibre Channel switching modules support oversubscription on switches
with shared rate mode configurations.
oversubscribed interfaces configured in shared mode.
Table 22-15
Switching
Module Type
48 ports
24 ports
By default, all 48-port and 24-port 4-Gbps Fibre Channel switching modules have restrictions on
oversubscription ratios enabled.
As of Cisco SAN-OS Release 3.1(1) and later, you can disable restrictions on oversubscription ratios.
All ports in 48-port and 24-port modules can be configured to operate at 4 Gbps in shared mode–even if
other ports in the port group are configured in dedicated mode–regardless of available bandwidth.
However, when oversubscription ratio restrictions are enabled you may not have all shared ports
operating at 4 Gbps. For example, oversubscription ratios are enabled, and you have configured three 4
Gbps dedicated ports in one port group, no other ports in the same port group can be configured to
operate at 4 Gbps.
For dedicated ports, oversubscription ratio restrictions do not apply to the shared pool in port groups. So
if oversubscription ratio restrictions are disabled, and you've configured three 4 Gbps dedicated ports in
one port group, then you can configure all other ports in the same port group to operate at a shared rate
of 4 Gbps.
When disabling restrictions on oversubscription ratios, all ports in shared mode on 48-port and 24-port
4-Gbps Fibre Channel switching modules must be shut down. When applying restrictions on
oversubscription ratios, you must take shared ports out of service.
OL-16184-01, Cisco MDS SAN-OS Release 3.x
Table 22-15
Bandwidth Allocation for Oversubscribed Interfaces
Configured Speed
Auto 4 Gbps
Auto (maximum is 2 Gbps)
2 Gbps
1 Gbps
Auto 4 Gbps
Auto (maximum is 2 Gbps)
2 Gbps
1 Gbps
Configuring Generation 2 Module Interface Shared Resources
describes the bandwidth allocation for
Reserved Bandwidth (Gbps)
Ratios enabled Ratios disabled
0.8 0.09
0.4 0.045
0.2 0.0225
1 0.27
0.5 0.135
0.25 0.067
Cisco MDS 9000 Family CLI Configuration Guide
Maximum
Bandwidth
(Gbps)
4
2
1
4
2
1
22-23