How to Configure Cisco Catalyst 3850 Traffic Monitoring14

Cisco Catalyst 3850 switches offer advanced traffic monitoring capabilities to provide visibility and control over network traffic. By leveraging these features, network administrators can gain valuable insights into traffic patterns, identify performance issues, and optimize network utilization.

Prerequisites* Cisco Catalyst 3850 switch with software version 16.6 or later
* SPAN or RSPAN-capable interface
* Monitoring tool, such as Wireshark or SPANalyzer

Configuration Steps

1. Enable SPAN/RSPAN

* Enter configuration mode: configure terminal
* Enable SPAN: span
* Define the source interface for mirroring traffic: source interface
* Define the destination interface for receiving mirrored traffic: destination interface
* Optionally, set the SPAN session name: session name
* Exit configuration mode: exit

2. Configure Monitoring Tool

* Connect your monitoring tool to the destination interface.
* Configure the monitoring tool to listen for traffic on the appropriate VLAN.
* Start capturing traffic using the monitoring tool.

3. Verify Configuration

* Use the show span database command to verify the SPAN configuration.
* Use the show span session command to view session-specific information.
* Check the monitoring tool to ensure it is receiving and displaying traffic.

Advanced Configuration

1. Configure SPAN Filters

* Use access control lists (ACLs) to filter specific traffic based on source/destination IP addresses, ports, or protocols.
* Add the ACL to the SPAN configuration: source-access-list

2. Configure RSPAN Encapsulation

* Enable RSPAN encapsulation to extend SPAN functionality across multiple switches.
* Set the RSPAN VLAN ID: rsnpan vlan
* Configure the RSPAN source interface: rsnpan source interface
* Configure the RSPAN destination interface: rsnpan destination interface

3. Monitor Specific Traffic Types

* Use NetFlow or sFlow to monitor specific traffic types, such as VoIP or video.
* Configure NetFlow: ip flow monitor
* Configure sFlow: sflow monitor

Benefits of Traffic Monitoring* Improved visibility into network traffic patterns
* Identification of performance issues, such as bottlenecks and latency
* Troubleshooting network connectivity problems
* Security monitoring and intrusion detection
* Compliance with regulatory requirements

Additional Tips* Use a dedicated monitoring port for SPAN/RSPAN to avoid impacting production traffic.
* Keep SPAN sessions to a minimum to avoid overwhelming the monitoring tool.
* Use appropriate SPAN filters to capture only relevant traffic.
* Regularly review traffic monitoring data to identify trends and potential issues.

2024-11-02

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