Default Settings for SPAN
• VLAN SPAN monitors only the traffic that enters Layer 2 ports in the VLAN.
• VLANs are supported as SPAN sources only in the ingress direction.
• FEX ports are supported as SPAN sources in the ingress direction for all traffic and in the egress direction
• When SPAN/ERSPAN is used to capture the Rx traffic on the FEX HIF ports, additional VNTAG and
• You can configure a SPAN session on the local device only.
• SPAN is supported in Layer 3 mode; however, SPAN is not supported on Layer 3 subinterfaces or Layer
• Cisco NX-OS does not span Link Layer Discovery Protocol (LLDP) or Link Aggregation Control
• SPAN sessions cannot capture packets with broadcast or multicast MAC addresses that reach the
Default Settings for SPAN
The following table lists the default settings for SPAN parameters.
Parameters
SPAN sessions
Configuring SPAN
Cisco NX-OS commands for this feature may differ from those in Cisco IOS.
Note
Configuring a SPAN Session
You can configure a SPAN session on the local device only. By default, SPAN sessions are created in the
shut state.
For bidirectional traditional sessions, you can configure the sessions without specifying the direction of
Note
the traffic.
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only for known Layer 2 unicast traffic.
802.1q tags are present in the captured traffic.
3 port-channel subinterfaces.
Protocol (LACP) packets when the source interface is not a host interface port channel.
supervisor, such as ARP requests and Open Shortest Path First (OSPF) protocol hello packets, if the
source of the session is the supervisor Ethernet in-band interface. To capture these packets, you must
use the physical interface as the source in the SPAN sessions.
Default
Created in the shut state
Configuring SPAN