> # Guidelines and Limitations

> # SPAN Configuration Guidelines

> The following guidelines and limitations apply for SPAN configurations:

> - You can configure up to 16 SPAN sessions with multiple ingress (Rx) sources.
> - You can configure a maximum of three SPAN sessions with one egress (Tx) port.
> - In a 32-port switching module, you must configure the same session in all four ports in one port group (unit). If you wish, you can also configure only two or three ports in this unit.
> - SPAN frames are dropped if the sum of the bandwidth of the sources exceeds the speed of the destination port.
> - Frames dropped by a source port are not spanned.
> - SPAN does not capture pause frames in a Fibre Channel over Ethernet (FCoE) network because pause frames sent from the virtual expansion (VE) port are generated and terminated by the outermost MAC layer. For more information on FCoE, see the Cisco NX-OS FCoE Configuration Guide for Cisco Nexus 7000 and Cisco MDS 9500.

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