> # Generation 1 Interface Configuration Guidelines

> The Generation 1 interfaces configuration guidelines apply to the following hardware:

> - The 32-port, 2-Gbps or 1-Gbps switching module interfaces
> - The Cisco MDS 9140 and 9120 switch interfaces

> Note Due to the hardware design of the MDS 9134 switch, we do not support interface out-of-service action on either of its two 10-Gigabit ports. This is because no internal port hardware resource is released when an out-of-service action is performed on these 10-Gigabit ports.

> When configuring these host-optimized ports, the following port mode guidelines apply:

> - You can configure only the first port in each 4-port group (for example, the first port in ports 1-4, the fifth port in ports 5-8, and so on) as an E port. If the first port in the group is configured as an E port, the other three ports in each group (ports 2-4, 6-8, and so on) are not usable and remain shutdown.
> - If you execute the write erase command on a 32-port switching module, and then copy a saved configuration to the switch from a text file that contains the no system default switchport shutdown command, you need to copy the text file to the switch again for the E ports to come up without manual configuration.
> - If any of the other three ports are enabled, you cannot configure the first port as an E port. The other three ports continue to remain enabled.
> - The auto mode is not allowed in a 32-port switching module or the host-optimized ports in the Cisco 9100 Series (16 host-optimized ports in the Cisco MDS 9120 switch and 32 host-optimized ports in the Cisco MDS 9140 switch).
> - The default port mode is Fx (Fx negotiates to F or FL) for 32-port switching modules.
> - The 32-port switching module does not support FICON.

> Note We recommend that you configure your E ports on a 16-port switching module. If you must configure an E port on a 32-port host-optimized switching module, the other three ports in that 4-port group cannot be used.

> Note In the Cisco MDS 9100 Series, the groups of ports that are located on the left and outlined in white are full line rate. The other ports are host-optimized. Each group of 4 host-optimized ports have the same features as for the 32-port switching module.

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