HP Cisco MDS 9120 Cisco MDS 9000 Family Fabric Manager Configuration Guide, Re - Page 385

Chapter 20 Configuring Interfaces Fibre Channel Interfaces Send documentation comments to [email protected] Autosensing Autosensing speed is enabled on all 4-Gbps switching module interfaces by default. This configuration enables the interfaces to operate at speeds of 1 Gbps, 2 Gbps, or 4 Gbps on the 4-Gbps switching modules. When autosensing is enabled for an interface operating in dedicated rate mode, 4-Gbps of bandwidth is reserved, even if the port negotiates at an operating speed of 1-Gbps or 2-Gbps. To avoid wasting unused bandwidth on 48-port and 24-port 4-Gbps Fibre Channel switching modules, you can specify that only 2 Gbps of required bandwidth be reserved, not the default of 4 Gbps. This feature shares the unused bandwidth within the port group provided that it does not exceed the rate limit configuration for the port. You can also use this feature for shared rate ports that are configured for autosensing. Tip When migrating a host that supports up to 2-Gbps traffic (that is, not 4-Gbps with autosensing capabilities) to the 4-Gbps switching modules, use autosensing with a maximum bandwidth of 2-Gbps. About Interface Descriptions Interface descriptions should help you identify the traffic or use for that interface. The interface description can be any alphanumeric string. About Frame Encapsulation You can set the frame format to EISL for all frames transmitted by the interface in SD port mode. If you sent the frame encapsulation to EISL, all outgoing frames are transmitted in the EISL frame format, irrespective of the SPAN source(s). See the "Monitoring Network Traffic Using SPAN" section on page 62-1. Refer to the Cisco MDS 9000 Family CLI Configuration Guide to configure frame encapsulation on an interface. About Receive Data Field Size You can also configure the receive data field size for Fibre Channel interfaces. If the default data field size is 2112 bytes, the frame length will be 2148 bytes. Configuring Receive Data Field Size You can also configure the receive data field size for Fibre Channel interfaces. If the default data field size is 2112 bytes, the frame length will be 2148 bytes. To configure the receive data field size using Fabric Manager, follow these steps: Step 1 Step 2 Expand Switches > Interfaces and then select FC Physical. You see the interface configuration in the Information pane. Click the Other tab and set the RxDataFieldSize field (see Figure 20-4). OL-16184-01, Cisco MDS SAN-OS Release 3.x Cisco MDS 9000 Family CLI Configuration Guide 20-13