SVI traffic counter in VxLAN

[cisco9k]

Hi everyone,

I've a question about monitoring interface vlan traffic in nexus 9k.In nexus 9k does't count the interface vlan traffic by default and need to apply commad below:

hardware profile svi-and-ai flex-stats-enable

but this command needs to disable VxLAN and MPLS feature so how can I monitor SVI traffic when I have VxLAN enabled?

Thanks in advance

[vishalbhandari]

To monitor interface VLAN (SVI) traffic on a Nexus 9000 switch while VxLAN is enabled, you indeed face the limitation where enabling the flexible statistics (with the hardware profile svi-and-ai flex-stats-enable command) requires disabling VxLAN and MPLS. However, there are alternative methods to monitor SVI traffic without disabling these features:

Alternative Methods for Monitoring SVI Traffic

1. Using Ingress and Egress Policies: You can use ACLs (Access Control Lists) to capture and count traffic. Although this method doesn't give a direct count of all traffic through the SVI, it can be useful for monitoring specific types of traffic.

   • Step 1: Create an ACL to match the traffic you want to monitor.
   • Step 2: Apply the ACL to the SVI interface for both ingress and egress traffic.
   • Step 3: Use the show access-lists command to monitor the counters for the ACL.

   Example:

   plaintext

   ip access-list VLAN_TRAFFIC permit ip any any interface Vlan10 ip access-group VLAN_TRAFFIC in ip access-group VLAN_TRAFFIC out

2. NetFlow: NetFlow can be used to monitor and analyze traffic flows through the switch, including SVI traffic. It provides detailed information about traffic patterns and can be used for traffic accounting and monitoring.

   • Step 1: Configure a Flow Exporter.
   • Step 2: Configure a Flow Monitor and apply it to the SVI.
   • Step 3: Collect and analyze the data using a NetFlow collector.

   Example:

   plaintext

   flow exporter EXPORTER-1 destination 10.1.1.1 source Vlan10 transport udp 2055 flow monitor FLOW-MON record netflow-original exporter EXPORTER-1 interface Vlan10 ip flow monitor FLOW-MON input ip flow monitor FLOW-MON output

3. SNMP: SNMP (Simple Network Management Protocol) can be used to poll interface statistics, including SVIs. While this method might not provide as granular traffic statistics as flexible stats, it can still be used for basic traffic monitoring.

   • Step 1: Ensure SNMP is configured on your Nexus 9000.
   • Step 2: Use an SNMP tool to poll the traffic counters for the SVI interfaces.

   Example:

   plaintext

   snmp-server community public ro snmp-server host 10.1.1.2 version 2c public

4. SPAN/RSPAN/ERSPAN: You can use SPAN (Switch Port Analyzer), RSPAN (Remote SPAN), or ERSPAN (Encapsulated RSPAN) to monitor the traffic on SVI interfaces by mirroring the traffic to another port or an IP destination.

   • Step 1: Configure a SPAN session to capture traffic on the SVI.
   • Step 2: Use a traffic analyzer (like Wireshark) on the destination port to analyze the mirrored traffic.

   Example:

   plaintext

   monitor session 1 source interface Vlan10 both destination interface Ethernet1/1

   While the hardware profile svi-and-ai flex-stats-enable command cannot be used with VxLAN enabled, the above methods provide alternative ways to monitor SVI traffic. Each method has its own strengths and can be chosen based on the specific monitoring requirements and network setup.

[cisco9k]

Hi,
Thanks for your reply.The problem is when there isn't SVI counter you can't
monitor with SNMP for example if add the sensor in prtg there will be no
graphs.