Dedicated Mode; Shared Mode; Dynamic Bandwidth Management - HP Cisco MDS 9216 - Fabric Switch Configuration Manual

About Generation 2 Modules and Switches
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
2. By default, all ports in a 24-port 4-Gbps switching module operate in shared mode with administrative operating speed set to
Note Port rate modes are supported on all Generation 2 modules and fabric switches. Port rate modes are not
supported on the Cisco Fabric Switch for HP c-Class BladeSystem, and the Cisco Fabric Switch for IBM
BladeCenter.

Dedicated Mode

When port rate mode is configured as dedicated, a port is allocated required fabric bandwidth and related
resources to sustain line rate traffic at the maximum operating speed configured for the port. In this
mode, ports do not use local buffering and all receive buffers are allocated from a global buffer pool (see
the
Table 22-4
modules.
Table 22-4
Configured Speed
Auto
4-Gbps
Auto with 2-Gbps maximum
2-Gbps
1-Gbps
Note 10-Gbps ports in auto mode only support auto speed mode at 10 Gbps.

Shared Mode

When port rate mode is configured as shared, multiple ports within a port group share data paths to the
switch fabric so that fabric bandwidth and related resources are shared. Often, the available bandwidth
to the switch fabric may be less than the negotiated operating speed of a port. Ports in this mode use local
buffering for the BB_credit buffers.
All ports in switching modules where bandwidth is shared support 1-Gbps, 2-Gbps, or 4-Gbps traffic.
However, it is possible to configure one or more ports in a port group to operate in dedicated mode with
1-Gbps, 2-Gbps or 4-Gbps operating speed.

Dynamic Bandwidth Management

On port switching modules where bandwidth is shared, the bandwidth available to each port within a port
group can be configured based on the port rate mode and speed configurations. Within a port group, some
ports can be configured in dedicated mode while others operate in shared mode.
Cisco MDS 9000 Family CLI Configuration Guide
22-6
auto. All ports in a 24-port 4-Gbps switching module can operate in dedicated mode with a 2-Gbps operating speed. However,
if you configure one or more ports to operate in 4-Gbps dedicated mode, some of the other ports in the module would have
to operate in shared mode
"Buffer Pools" section on page
show the amount of bandwidth reserved for a configured port speed on 4-Gbps switching
Bandwidth Reserved for the Port Speeds on 4-Gbps Switching Modules
Chapter 22
22-8).
Reserved Bandwidth
4 Gbps
2 Gbps
1 Gbps
Configuring Generation 2 Switches and Modules
OL-16184-01, Cisco MDS SAN-OS Release 3.x