> # Port Rate Modes

> In Generation 2, Generation 3, and Generation 4 modules, you can configure the port rate modes. The port rate mode configuration is used to determine the bandwidth allocation for ports in a port group. Two port rate modes are supported:

> - Dedicated Rate Mode—A port is allocated required fabric bandwidth to sustain line traffic at the maximum operating speed configured on the port. For more information, see the "Dedicated Rate Mode" topic.
> - Shared Rate Mode—Multiple ports in a port group share data paths to the switch fabric and share bandwidth. For more information, see the "Shared Rate Mode" topic.

> Note In Generation 1 modules, you cannot configure the port rate modes. The mode is determined implicitly based on the port mode and line card type.

> Note Port rate modes are not supported on the Cisco Fabric Switch for HP c-Class Blade System, and the Cisco Fabric Switch for IBM Blade Center.

> Table 13-3 shows the modules that support dedicated, shared, and the default rate modes.

> Table 13-3 Port Rate Mode Support on Generation 2, Generation 3, and Generation 4 Modules and Switches
> Part Number | Product Name/ Description | Supports Dedicated Rate Mode | Supports Shared Rate Mode | Default Speed Mode and Rate Mode on All Ports
> --- | --- | --- | --- | ---
> Generation 4 Modules
> DS-X9248-256K9 | 48-port 8-Gbps Advanced Fibre Channel switching module | Yes | Yes1 | Auto, Shared
> DS-X9232-256K9 | 32-port 8-Gbps Advanced Fibre Channel switching module | Yes | Yes1 | Auto, Shared
> Generation 3 Modules
> DS-X9248-96K9 | 48-Port 8-Gbps Fibre Channel switching module | Yes | Yes2 | Auto, Shared
> DS-X9224-96K9 | 24-Port 8-Gbps Fibre Channel switching module | Yes | Yes2 | Auto, Shared
> DS-X9248-48K9 | 4/44-Port 8-Gbps Host-Optimized Fibre Channel switching module | Yes | Yes2 | Auto Max 4 Gbps, Shared
> Generation 3 Fabric Switches
> DS-C9148-K9 (Cisco MDS 9148 Fabric switch) | 48-port 8-Gbps Fabric switch | Yes | No | Auto, Dedicated
> Generation 2 Modules
> DS-X9148 | 48-port 4-Gbps Fibre Channel switching module 3 | Yes | Yes | Auto, Shared
> DS-X9124 | 24-port 4-Gbps Fibre Channel switching module | Yes | Yes | Auto, Shared
> DS-X9304-18K9 (MSM-18/4 Multiservice module) | 18-port 4-Gbps Fibre Channel switching module with 4-Gigabit Ethernet ports | Yes | Yes | Auto, Shared
> DS-X9112 | 12-port 4-Gbps Fibre Channel switching module | Yes | No | Auto, Dedicated
> DS-X9704 | 4-port 10-Gbps Fibre Channel switching module | Yes | No | Auto, Dedicated
> Generation 2 Fabric Switches
> DS-C9134-K9 (Cisco MDS 9134 Fabric switch) | 32-port 4-Gbps Fabric switch | Yes | Yes | Auto, Shared
> 2-port 10-Gbps Fabric switch | Yes | No | Auto, Dedicated
> DS-C9124-K9 (Cisco MDS 9124 Fabric switch) | 24-port 4-Gbps Fabric switch4 | Yes | No | Auto, Dedicated
> DS-C9222i-K9 (Cisco MDS 9222i Multiservice Modular switch) | 18-port 4-Gbps Fibre Channel switch with 4-Gigabit Ethernet IP storage services ports, and a modular expansion slot to host Cisco MDS 9000 Family Switching and Services Modules | Yes | Yes | Auto, Shared

> 1Supports shared rate mode. 2Shared rate mode is supported on Fx ports only and no ISLs. 3All ports in a 48-port 4-Gbps switching module can operate in dedicated rate mode with a 1-Gbps operating speed. However, if you configure one or more ports to operate in 2-Gbps or 4-Gbps dedicated rate mode, some of the other ports in the port group would have to operate in shared mode. 4All ports in a 24-port 4-Gbps switching module can operate in dedicated rate mode with a 2-Gbps operating speed. However, if you configure one or more ports to operate in 4-Gbps dedicated rate mode, some of the other ports in the port group would have to operate in shared mode.

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