Disabling Restrictions On Oversubscription Ratios - Cisco AP775A - Nexus Converged Network Switch 5010 Configuration Manual

Chapter 22 Configuring Generation 2 and Generation 3 Switching Modules
Configuring Module Interface Shared Resources
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
All ports in the 48-port and 24-port 8-Gbps modules can be configured to operate at 8 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
8-Gbps module ports operating at 8 Gbps.
On the 48-port and 24-port 8-Gbps modules, if you have configured one 8-Gbps dedicated port in one
port group, no other ports in the same port group can be configured to operate at 8-Gbps dedicated mode.
You can have any number of 8-Gbps shared and 4-Gbps dedicated or shared ports. On the 4/44-port
8-Gbps module, only one port per port group can be configured in 8-Gbps dedicated or shared mode.
In the following example, a 24-port 4-Gbps module has oversubscription ratios enabled and three
dedicated ports in one port group operating at 4-Gbps. 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 have 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 or any 8-Gbps Fibre Channel switching modules must be shut down. When applying restrictions
on oversubscription ratios, you must take shared ports out of service.
When restrictions on oversubscription ratios are disabled, the bandwidth allocation among the shared
Note
ports is proportionate to the configured speed. If the configured speed is auto on Generation 2 modules,
then bandwidth is allocated assuming a speed of 4 Gbps. For example, if you have three shared ports
configured at 1, 2, and 4 Gbps, then the allocated bandwidth ratio is 1:2:4.
As of Cisco SAN-OS Release 3.0 and NX-OS Release 4.1(1) or when restrictions on oversubscription
ratios are enabled, the port bandwidths are allocated in equal proportions, regardless of port speed, so,
the bandwidth allocation for the same three ports mentioned in the example would be 1:1:1.

Disabling Restrictions on Oversubscription Ratios

Before disabling restrictions on oversubscription ratios, ensure that you have explicitly shut down shared
ports. To disable restrictions on oversubscription ratios on multiple 48-port or 24-port 4-Gbps, or any
8-Gbps Fibre Channel switching modules using Device Manager, follow these steps:
Step 1 Choose Physical > Modules.
You see the Module dialog box as shown in Figure 22-13.
Figure 22-13 Module Dialog Box
Cisco MDS 9000 Family Fabric Manager Configuration Guide
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OL-17256-03, Cisco MDS NX-OS Release 4.x