Configuring Oversubscription Ratio Restrictions - Cisco MDS 9000 Series Configuration Manual

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
fc7/42
fc7/43
fc7/44
fc7/45
fc7/46
fc7/47
fc7/48

Configuring Oversubscription Ratio Restrictions

The 48-port and 24-port 4-Gbps, and all 8-Gbps Fibre Channel switching modules support
oversubscription on switches with shared rate mode configurations. By default, all 48-port and 24-port
4-Gbps, and 8-Gbps Fibre Channel switching modules have restrictions on oversubscription ratios
enabled. As of Cisco SAN-OS Release 3.1(1) and NX-OS Release 4.1(1), you can disable restrictions
on oversubscription ratios.
Table 3-9
on the 4-Gbps and 8-Gbps modules.
Table 3-9
Switching
Module
48-Port 8-Gbps
Fibre Channel
Module
24-Port 8-Gbps
Fibre Channel
Module
4/44-Port
8-Gbps
Host-Optimized
Fibre Channel
Module
48-port 4-Gbps
Fibre Channel
switching
module
24-port 4-Gbps
Fibre Channel
switching
module
All ports in the 48-port and 24-port 4-Gbps 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
4-Gbps module ports operating at 4 Gbps.
Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
3-26
describes the bandwidth allocation for oversubscribed interfaces configured in shared mode
Bandwidth Allocation for Oversubscribed Interfaces
Configured Speed
Auto 8 Gbps
Auto Max 4 Gbps
Auto Max 2 Gbps
Auto 8 Gbps
Auto Max 4 Gbps
Auto Max 2 Gbps
8 Gbps
Auto Max 4 Gbps
Auto Max 2 Gbps
1 Gbps
Auto 4 Gbps
Auto Max 2 Gbps
1 Gbps
Auto 4 Gbps
Auto Max 2 Gbps
1 Gbps
Chapter 3 Configuring Fibre Channel Interfaces
32 4.0 shared
32 4.0 shared
32 4.0 shared
32 4.0 shared
32 4.0 shared
32 4.0 shared
32 4.0 shared
Reserved Bandwidth (Gbps)
Ratios enabled Ratios disabled
0.36 0.2
0.24 0.1
0.12 0.05
0.8 0.8
0.4 0.4
0.2 0.2
0.87 0.16
0.436 0.08
0.218 0.04
0.109 0.02
0.8 0.09
0.4 0.045
0.2 0.0225
1 0.27
0.5 0.135
0.25 0.067
OL-19445-02, Cisco MDS NX-OS Release 4.2(x)
Maximum
Bandwidth
(Gbps)
8
4
2
8
4
2
8
4
2
1
4
2
1
4
2
1