Cisco Nexus 5000 Series and Cisco Nexus 2000 Series Release Notes,Cisco NX-OS Release 5.1(3)N2(1a) and NX-OS Release 5.1(3)N2(1)

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Cisco Nexus 5000 Series and Cisco Nexus 2000 Series Release Notes, Cisco NX-OS Release 5.1(3)N2(1a) and NX-OS Release 5.1(3)N2(1)
OL-26652-02
Limitations
If you add an interface Ethernet100/1/2 as a tx-source to a different SPAN session (session-2) the
the following error is displayed:
swor28(config)# monitor session 2
swor28(config-monitor)# source interface ethernet 100/1/2 tx
ERROR: Eth100/1/2: Ports on a fex can be tx source in one session only
swor28(config-monitor)#
• When a FEX port is configured as a tx-source, the multicast traffic on all VLANs for which the
tx-source port is a member, is spanned. The FEX port sends out only multicast packets that are not
filtered by IGMP snooping. For example, if FEX ports 100/1/1-12 are configured on VLAN 11 and
the switch port 1/5 sends multicast traffic on VLAN 11 in a multicast group, and hosts connected to
FEX ports 100/1/3-12 are interested in receiving that multicast traffic (through IGMP), then that
multicast traffic goes out on FEX ports 100/1/3-12, but not on 100/1/1-2.
If you configure SPAN Tx on port 100/1/1, although the multicast traffic does not egress out of port
100/1/1, the SPAN destination does receive that multicast traffic, which is due to a design limitation.
• When a FEX port is configured as both SPAN rx-source and tx-source, the broadcast, non-IGMP
Layer-2 multicast, and unknown unicast frames originating from that port may be seen twice on the
SPAN destination, once on the ingress and once on the egress path. On the egress path, the frames
are filtered by the FEX to prevent them from going out on the same port on which they were
received. For example, if FEX port 100/1/1 is configured on VLAN 11 and is also configured as
SPAN rx-source and tx-source and a broadcast frame is received on that port, the SPAN destination
recognizes two copies of the frame, even though the frame is not sent back on port 100/1/1.
• A FEX port cannot be configured as a SPAN destination. Only a switch port can be configured and
used as a SPAN destination.
• Cisco NX-OS Release 5.1(3)N2(1) does not support SPAN on a VM FEX.
Checkpoint and Configuration Rollback Limitation
When FCoE is enabled, the checkpoint and configuration rollback functionality is disabled.
Layer 3 Limitations
Asymmetric Configuration
In a vPC topology, two Cisco Nexus 5000 switches configured as vPC peer switches need to be
configured symmetrically for Layer 3 configurations such as SVIs, Peer Gateway, routing protocol and
policies, and RACLs.
Note vPC consistency check does not include Layer 3 parameters.
SVI
When a Layer 3 module goes offline, all non-management SVIs are shut down. An SVI can be
configured as a management SVI using the interface vlan command and configuring management. This
configuration allows traffic to the management SVIs to not go throught the Layer 3 module which
maintains connectivity in case of a Layer 3 module failure.