Nexus 5548 SPAN - VLAN as source

[alpritchard]

i have a requirement to provide VOIP recording using SPAN sessions on a NX 5548.

Can someone confirm please whether a VLAN can be used as a source in multiple SPAN sessions on a 5548 ?

I.e. 

monitor session 1 – source vlan AA, dest port X

monitor session 2 – source vlan AA, dest port Y

I understand that a physical port can be used in multiple SPAN sessions but am not clear if this also applies to VLAN's

thanks in advance

[rsimoni]

Hi,

I am afraid that you cannot do that.

See

http://www.cisco.com/en/US/docs/switches/datacenter/nexus5000/sw/system_management/513_n1_1/b_Cisco_n5k_system_mgmt_cg_rel_513_n1_1_chapter_010000.html#con_1167251

Characteristics of Source Ports

A source port, also called a monitored port, is a switched interface that you monitor for network traffic analysis. The switch supports any number of ingress source ports (up to the maximum number of available ports on the switch) and any number of source VLANs or VSANs.

A source port has these characteristics:

• Can be of any port type: Ethernet, Fibre Channel, virtual Fibre Channel, port channel, SAN port channel, VLAN, and VSAN.
• Cannot be monitored in multiple SPAN sessions.
• Cannot be a destination port.
• Each source port can be configured with a direction (ingress, egress, or both) to monitor. For VLAN and VSAN sources, the monitored direction can only be ingress and applies to all physical ports in the group. The RX/TX option is not available for VLAN or VSAN SPAN sessions.
• Beginning with Cisco NX-OS Release 5.0(2)N1(1), Port Channel and SAN Port Channel interfaces can be configured as ingress or egress source ports.
• Source ports can be in the same or different VLANs or VSANs.
• For VLAN or VSAN SPAN sources, all active ports in the source VLAN or VSAN are included as source ports.
• For Cisco NX-OS Release 4.2(1)N2(1) and earlier, the Cisco Nexus 5010 Switch and the Cisco Nexus 5020 Switch supports a maximum of two egress SPAN source ports.
• Beginning with NX-OS Release 5.0(2)N1(1), there is no limit to the number of egress SPAN source ports.
• The limit on the number of egress (TX) sources in a monitor session has been lifted.
• On the Cisco Nexus 5548 Switch, Fibre Channel ports and VSAN ports cannot be configured as ingress source ports in a SPAN session.

Riccardo

[alpritchard]

ok i had hoped this was not the case as another post seemed to suggest physical ports could be used more than once in SPAN sessions..

see

https://supportforums.cisco.com/message/3369370#3369370

[rsimoni]

indeed, in that thread the poster suggested that such configuration is possible. Actually we don't know if that worked for real.

Honestly I don't have first-hand experience on this.

I suggest you to give a go in the lab and check this out. Officially it should not work though.

Riccardo