Cisco Nexus 7000 Series Configuration Manual page 315

Configuring SPAN
• You can configure an RSPAN VLAN for use only as a SPAN session source.
• You can configure a SPAN session on the local device only.
• If you span a fabricpath core interface when inter-VLAN routing is enabled across Layer 2 multi-path
(L2MP), it is not possible to capture the traffic egressing out of the core interface.
• SPAN is supported on Fabric Extender interfaces in Layer 2 access mode, Layer 2 trunk mode, and
Layer 3 mode. Layer 3 subinterfaces are not supported.
• Cisco NX-OS does not span Link Layer Discovery Protocol (LLDP) or Link Aggregation Control
Protocol (LACP) packets when the source interface is a Fabric Extender HIF (downlink) port or HIF
port channel.
• SPAN sessions cannot capture packets with broadcast or multicast MAC addresses that reach the
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.
• The rate limit percentage of a SPAN session is based on 10G, 40G, and 100G for the respective modules
(that is, 1 percent corresponds to 0.1G, 0.4G, or 1G respectively), and the value is applied per every
forwarding engine instance.
• Beginning with Cisco NX-OS Release 6.1, SPAN is supported for Supervisor 2.
• 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.
• On both Supervisor 1 and Supervisor 2, you cannot monitor the FCoE inband traffic.
• You can monitor both ingress and egress FCoE traffic can be monitored in a local SPAN session through
Ethernet interfaces, including shared interfaces, or VLANs. For shared interfaces, you can monitor the
FCoE traffic only in the storage VDC.
• The MAC in MAC (MiM) header in SPAN copies is preserved for the following SPAN destinations:
• The MiM header in SPAN copies is not preserved for the following SPAN destinations:
◦ For Supervisor 2 and Supervisor 2e systems, all the SPAN sessions can support an inband SPAN
source.
◦ Only one VDC can support inband SPAN at a time.
• F2e modules with Release 6.2 or later releases.
• F3 series modules with any Cisco NX-OS Release.
• For F3 series modules with Release 6.2.(6a), 6.2.(6b), or 6.2(8), the Fabricpath (FP) header is
preserved unconditionally. In Release 6.2.10, the FP header is preserved by default, but this behavior
can changed by using the switchport monitor exclude header command to remove the FP or
VLAN tag header for a specified SPAN destination in a VDC or the system default switchport
monitor exclude header command to remove the FP or VLAN tag header for all destinations
ports in the VDC. In Release 6.2.12, you can remove the FabricPath and VLAN tag headers using
the switchport monitor exclude header command at the SPAN destination.
• F1 and F2 series modules with any Cisco NX-OS Release.
Cisco Nexus 7000 Series NX-OS System Management Configuration Guide
General SPAN Guidelines and Limitations
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