SVI and Subinterface Ingress/Egress Unicast Counters

[Bernd Nies]

Hi,

We migrated from Catalyst 6500 to Nexus 93180YC-FX3 core switches in vPC configuration running NXOS 10.2.4. What I miss in the SNMP monitoring are the traffic counters for the VLAN interfaces. I found the following in the Nexus 9000 configuration guide [1].

configure terminal
hardware profile svi-and-si flex-stats-enable
copy running-config startup-config
reload

Is this safe to do or what are the drawbacks that it is not enabled by default? We're using only vPC, OSPF and HSRP features. No VxLAN or MPLS.

Regards, Bernd

[1] https://www.cisco.com/c/en/us/td/docs/switches/datacenter/nexus9000/sw/93x/interfaces/configuration/guide/b-cisco-nexus-9000-nx-os-interfaces-configuration-guide-93x/b-cisco-nexus-9000-nx-os-interfaces-configuration-guide-93x_chapter_0101.html

[M02@rt37 · Accepted solution]

Hello @Bernd Nies 

The drawback of not having this feature enabled by default is that you won't have visibility into the traffic statistics for your VLAN interfaces, which can be useful for troubleshooting and monitoring network performance.

Enabling this feature may result in a small increase in CPU and memory usage on the switches, but this should be negligible for most networks. Additionally, enabling the feature requires a switch reload, which will result in a brief disruption to network connectivity.

Overall, if you need to monitor traffic statistics for your VLAN interfaces, enabling the "flex-stats-enable" feature should be a safe and effective solution. Just be sure to follow the documented steps and best practices for configuration and testing.

[cisco9k]

Hello

after I installed feature set mpls the number of counters will not increase.do you have any idea?

Regards

[Bernd Nies]

Thanks. Seems to work fine after activation.

[waqaswilan2026]

SVI (Switched Virtual Interface) and subinterface ingress/egress unicast counters are metrics used in network monitoring and troubleshooting. SVI is a virtual interface on a switch used to route traffic between VLANs. Subinterfaces are logical interfaces created within a physical interface, commonly used in router-on-a-stick configurations for VLAN routing.

Ingress counters measure incoming unicast packets, while egress counters measure outgoing unicast packets. Monitoring these counters helps administrators track traffic patterns, identify potential bottlenecks, and troubleshoot connectivity issues within VLANs or subnets.