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Cisco MDS 9000 Family NX-OS Interfaces Configuration Guide
OL-29284-01, Release 6.x
Chapter 3 Configuring Fibre Channel Interfaces
Information About Fibre Channel Interfaces
Port Speed
The port speed on an interface, combined with the rate mode, determines the amount of shared resources
available to the ports in the port group on a 48-port, 24-port 4-Gbps, or any 8-Gbps Fibre Channel
switching module. Especially in the case of dedicated rate mode, the port group resources are reserved
even though the bandwidth is not used. For example, on Generation 2 modules, if an interface is
configured for autosensing (auto) and dedicated rate mode, then 4 Gbps of bandwidth is reserved even
though the maximum operating speed is 2 Gbps. For the same interface, if autosensing with a maximum
speed of 2 Gbps (auto max 2000) is configured, then only 2 Gbps of bandwidth is reserved and the
unused 2 Gbps is shared with the other interface in the port group.
Note • The Generation 2, 4-port 10-Gbps switching module supports 10-Gbps traffic only.
• On Generation 2, 4-Gbps modules, setting the port speed to auto enables autosensing, which
negotiates to a maximum speed of 4 Gbps.
• On Generation 3, 8-Gbps modules, setting the port speed to auto enables autosensing, which
negotiates to a maximum speed of 8 Gbps.
• On Generation 4, 8-Gbps modules, setting the port speed to auto enables autosensing, which
negotiates to a maximum speed of 8 Gbps.
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 rate mode while others operate in shared mode.
Tab l e 3-8 Dedicated Rate Mode Bandwidth Reservation for Generation 3 Fibre Channel
Modules
Part Number
Product Name/
Description
Dedicated
Bandwidth
per Port
Maximum
Allowed Ports
That Can Come
Up Ports in Shared Mode
DS-X9224-96K9 24-port 8-Gbps
Fibre Channel
switching module
8 Gbps 8 Ports All the remaining ports
are 8 Gbps shared.
4 Gbps 24 Ports
DS-X9248-96K9 48-port 8-Gbps
Fibre Channel
switching module
8 Gbps 8 Ports All the remaining ports
are 8 Gbps shared.
4 Gbps 24 Ports
2 Gbps 48 Ports
DS-X9248-48K9 4/44-port 8-Gbps
Host-Optimized
Fibre Channel
switching module
8 Gbps 4 Ports All the remaining ports
are 4 Gbps shared (8 Gbps
of bandwidth can be
provided only to one port
per port group in
dedicated or shared rate
mode).
4 Gbps 12 Ports
2 Gbps 24 Ports
1 Gbps 48 Ports