System Management Configuration Guide, Cisco DCNM for LAN, Release 6.x
Configuring SPAN
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Configuring SPAN

Table Of Contents

Configuring SPAN

Information About SPAN

SPAN Sources

SPAN Destinations

SPAN Sessions

Virtual SPAN Sessions

Multiple SPAN Sessions

High Availability

Licensing Requirements for SPAN

Prerequisites

Platform Support

Configuring SPAN

Configuring a SPAN Session

Configuring a Virtual SPAN Session

Configuring an RSPAN VLAN

Shutting Down or Resuming a SPAN Session

Field Descriptions for SPAN

Local SPAN Session: Configuration: Session Settings Section

Local SPAN Session: Configuration: Source and Destination Section

Additional References

Related Documents

Standards

Feature History for SPAN


Configuring SPAN


This chapter describes how to configure an Ethernet Switched Port Analyzer (SPAN) to analyze traffic between ports on Cisco NX-OS devices.


Note The Cisco NX-OS release that is running on a managed device may not support all the features or settings described in this chapter. For the latest feature information and caveats, see the documentation and release notes for your platform and software release.


This chapter includes the following sections:

Information About SPAN

Licensing Requirements for SPAN

Prerequisites

Platform Support

Configuring SPAN

Field Descriptions for SPAN

Additional References

Feature History for SPAN

Information About SPAN

SPAN analyzes all traffic between source ports by directing the SPAN session traffic to a destination port with an external analyzer attached to it.

You can define the sources and destinations to monitor in SPAN sessions on the local device.

This section includes the following topics:

SPAN Sources

SPAN Destinations

SPAN Sessions

Virtual SPAN Sessions

Multiple SPAN Sessions

High Availability

SPAN Sources

The interfaces from which traffic can be monitored are called SPAN sources. Sources designate the traffic to monitor and whether to copy ingress, egress, or both directions of traffic. SPAN sources include the following:

Ethernet ports

VLANs—When a VLAN is specified as a SPAN source, all supported interfaces in the VLAN are SPAN sources.

Remote SPAN (RSPAN) VLANs

SPAN Destinations

SPAN destinations refer to the interfaces that monitor source ports. Destination ports receive the copied traffic from SPAN sources.

SPAN Sessions

You can create SPAN sessions designating sources and destinations to monitor.

Figure 5-1 shows a SPAN configuration. Packets on three Ethernet ports are copied to destination port Ethernet 2/5. Only traffic in the direction specified is copied.

Figure 5-1 SPAN Configuration

.

Virtual SPAN Sessions

You can create a virtual SPAN session to monitor multiple VLAN sources and choose only VLANs of interest to transmit on multiple destination ports. For example, you can configure SPAN on a trunk port and monitor traffic from different VLANs on different destination ports.

Figure 5-2 shows a virtual SPAN configuration. The virtual SPAN session copies traffic from the three VLANs to the three specified destination ports. You can choose which VLANs to allow on each destination port to limit the traffic that the device transmits on it. In Figure 5-2, the device transmits packets from one VLAN at each destination port.


Note Virtual SPAN sessions cause all source packets to be copied to all destinations, whether the packets are required at the destination or not. VLAN traffic filtering occurs at the egress destination port level.


Figure 5-2 Virtual SPAN Configuration

.

For information about configuring a virtual SPAN session, see the "Configuring a Virtual SPAN Session" section.

Multiple SPAN Sessions

You can define multiple SPAN sessions. You can shut down an unused SPAN session.

For information about shutting down SPAN sessions, see the "Shutting Down or Resuming a SPAN Session" section.

High Availability

The SPAN feature supports stateless and stateful restarts. After a reboot or supervisor switchover, applies the running configuration.

Licensing Requirements for SPAN

The following table shows the licensing requirements for this feature:

Product
License Requirement

Cisco DCNM

SPAN requires no license. Any feature not included in a license package is bundled with Cisco DCNM and is provided at no charge to you. For a complete explanation of the Cisco DCNM licensing scheme, see the Cisco DCNM Installation and Licensing Guide, Release 5.x.

Cisco NX-OS

SPAN requires no license. Any feature not included in a license package is bundled with the Cisco NX-OS system images and is provided at no extra charge to you. For an explanation of the Cisco NX-OS licensing scheme for your platform, see the licensing guide for your platform.


Prerequisites

The SPAN feature has the following prerequisite (for a full list of feature-specific prerequisites, see the platform-specific documentation):

System-message logging levels for the SPAN feature must meet or exceed Cisco DCNM requirements. During device discovery, Cisco DCNM detects inadequate logging levels and raises them to the minimum requirements. Cisco Nexus 7000 Series switches that run Cisco NX-OS Release 4.0 are an exception. For Cisco NX-OS Release 4.0, prior to device discovery, use the command-line interface to configure logging levels to meet or exceed Cisco DCNM requirements. For more information, see the Cisco DCNM Fundamentals Guide, Release 5.x.

Platform Support

The following platform supports this feature. For platform-specific information, including guidelines and limitations, system defaults, and configuration limits, see the corresponding documentation.

Platform
Documentation

Cisco Nexus 3000 Series switches

Cisco Nexus 3000 Series Switch Documentation

Cisco Nexus 7000 Series switches

Cisco Nexus 7000 Series Switch Documentation


Configuring SPAN

This section includes the following topics:

Configuring a SPAN Session

Configuring a Virtual SPAN Session

Configuring an RSPAN VLAN

Shutting Down or Resuming a SPAN Session

Configuring a SPAN Session

You can configure a SPAN session on the local device only.

For sources, you can specify Ethernet ports, port channels, VLANs, and RSPAN VLANs. You can specify private VLANs (primary, isolated, and community) in SPAN sources.

For destination ports, you can specify Ethernet ports or port channels in either access or trunk mode. You must enable monitor mode on all destination ports.

BEFORE YOU BEGIN

You must have already configured the destination ports in access or trunk mode. For more information, see the Interfaces Configuration Guide, Cisco DCNM for LAN, Release 5.x.

DETAILED STEPS


Step 1 From the Feature Selector pane, choose Interfaces > Traffic Monitoring > SPAN. The available devices appear in the Summary pane.

Step 2 From the Summary pane, double-click the device that you want to configure with a SPAN session to display the configured SPAN sessions.

Step 3 (Optional) To delete a SPAN session that you are no longer using, right-click the SPAN session and choose Delete.

Step 4 (Optional) To configure a new SPAN session from the menu bar, choose File > New Local SPAN Session.

a. (Only the first time you create a SPAN session) From the Summary pane, double-click the device that you want to configure with a SPAN session to display the configured SPAN sessions.

b. (Optional) To modify the session number, from the Summary pane, double-click the Session Id field and enter a session number from 1 to 18.


Note You can only modify the session number immediately after you create the session.


Step 5 From the Summary pane, choose the SPAN session to configure.

Step 6 From the Details pane, click the Configuration tab and expand the Session Settings section, if necessary.

Step 7 (Optional) To add a description of the SPAN session, specify it in the Description field.

Step 8 (Optional) In the Filtered VLANs field, click the down arrow to display and choose from the configured VLANs.

Step 9 Add source Ethernet ports to the SPAN session as follows:

a. From the Ports association panel, double-click the device and then double-click the desired slot to display ports.

b. Choose the port, right-click on the port row, and choose Add to SPAN Source to add this port to the SPAN session sources.

Step 10 Add source VLANs or RSPAN VLANs to the SPAN session as follows:

a. From the VLANs association panel, double-click the device to display the configured VLANs.

b. Choose the VLAN, right-click on the VLAN row, and choose Add to SPAN Source to add this VLAN to the SPAN session sources.

Step 11 Add destination Ethernet ports to the SPAN session as follows:

a. From the Ports association panel, double-click the device and then double-click the desired slot to display ports.

b. Choose an access or trunk port.

c. In the Monitor column, check the check box to enable monitoring on this port.

d. Right-click on the port row and choose Add to SPAN Destination to add this port to the SPAN session destinations.

Step 12 (Optional) To modify SPAN session source settings, follow these steps:

a. From the Details pane, click the Configuration tab and expand the Source and Destination section, if necessary.

b. To modify the ingress or egress choice for a source, check or uncheck the Ingress or Egress check box to activate the desired direction to monitor.

c. To delete a SPAN source or destination, choose the source or destination entry, right-click on it, and choose Delete.

Step 13 From the menu bar, choose File > Deploy to apply your changes to the device.


Configuring a Virtual SPAN Session

You can configure a virtual SPAN session to copy packets from source ports, VLANs, and RSPAN VLANs to destination ports on the local device.

For sources, you can specify ports, VLANs, or RSPAN VLANs.

For destination ports, you can specify Ethernet ports. You can choose which VLANs to allow on each destination port to limit the traffic that the device transmits on it.

BEFORE YOU BEGIN

You have already configured the destination ports in trunk mode. For more information, see the Interfaces Configuration Guide, Cisco DCNM for LAN, Release 5.x.

DETAILED STEPS


Step 1 From the Feature Selector pane, choose Interfaces > Traffic Monitoring > SPAN. The available devices appear in the Summary pane.

Step 2 From the Summary pane, double-click the device that you want to configure with a SPAN session to display the configured SPAN sessions.

Step 3 (Optional) To delete a SPAN session that you are no longer using, right-click the SPAN session and choose Delete.

Step 4 (Optional) To configure a new SPAN session from the menu bar, choose File > New Local SPAN Session.

a. (Only the first time you create a SPAN session) From the Summary pane, double-click the device that you want to configure with a SPAN session to display the configured SPAN sessions.

b. (Optional) To modify the session number, from the Summary pane, double-click the Session Id field and enter a session number from 1 to 18.


Note You can only modify the session number immediately after you create the session.


Step 5 From the Summary pane, choose the SPAN session to configure.

Step 6 From the Details pane, click the Configuration tab and expand the Session Settings section, if necessary.

Step 7 (Optional) To add a description of the SPAN session, specify it in the Description field.

Step 8 (Optional) In the Filtered VLANs field, click the down arrow to display and choose from the configured VLANs.

Step 9 Add source Ethernet ports to the SPAN session as follows:

a. From the Ports association panel, double-click the device and then double-click the desired slot to display ports.

b. Choose the port, right-click on the port row, and choose Add to SPAN Source to add this port to the SPAN session sources.

Step 10 Add source VLANs or RSPAN VLANs to the SPAN session as follows:

a. From the VLANs association panel, double-click the device to display the configured VLANs.

b. Choose the VLAN, right-click on the VLAN row, and choose Add to SPAN Source to add this VLAN to the SPAN session sources.

Step 11 Add destination Ethernet ports to the SPAN session as follows:

a. From the Ports association panel, double-click the device and then double-click the desired slot to display ports.

b. Choose an access or trunk port.

c. In the Monitor column, check the check box to enable monitoring on this port.

d. Right-click on the port row and choose Add to SPAN Destination to add this port to the SPAN session destinations.

Step 12 Limit the VLANs allowed on a trunk port by following these steps:

a. From the Feature Selector pane, choose Interfaces > Physical > Ethernet. The available devices appear in the Summary pane.

b. From the Summary pane, double-click the device and then double-click the slot that you want to configure.

c. Choose the trunk port to configure.

d. From the Details pane, click the Port Details tab and expand the Port Mode Settings section, if necessary.

e. Limit the VLANs on the trunk by clicking the Allowed VLANs field. The field displays configured VLANs that you can choose.

Step 13 From the menu bar, choose File > Deploy to apply your changes to the device.


Configuring an RSPAN VLAN

You can specify a remote SPAN (RSPAN) VLAN as a SPAN session source.

DETAILED STEPS


Step 1 From the Feature Selector pane, choose Switching > VLAN. The available devices appear in the Summary pane.

Step 2 From the Summary pane, double-click the device that you want to configure.

Step 3 Choose the VLAN to configure.

Step 4 From the Details pane, click the VLAN Details tab and expand the Advanced Settings section, if necessary.

Step 5 Check the RSPAN VLAN check box.

Step 6 From the menu bar, choose File > Deploy to apply your changes to the device.


Shutting Down or Resuming a SPAN Session

You can shut down SPAN sessions to discontinue the copying of packets from sources to destinations. This action can free up hardware resources to enable another session.

You can resume (enable) SPAN sessions to resume the copying of packets from sources to destinations. In order to enable a SPAN session that is already enabled but operationally down, you must first shut it down and then enable it.

DETAILED STEPS


Step 1 From the Feature Selector pane, choose Interfaces > Traffic Monitoring > SPAN.

The available devices appear in the Summary pane.

Step 2 From the Summary pane, double-click the device to display the configured SPAN sessions.

Step 3 From the Summary pane, choose the SPAN session to configure.

Step 4 From the Details pane, click the Configuration tab and expand the Session Settings section, if necessary.

Step 5 Resume (enable) the SPAN session by choosing Up in the Admin Status field.

Step 6 Shut down the SPAN session by choosing Down in the Admin Status field.


Note If a monitor session is enabled but its operational status is down, to enable the session, you must first shut down the session and then resume the session.



Field Descriptions for SPAN

This section includes the following field descriptions for SPAN:

Local SPAN Session: Configuration: Session Settings Section

Local SPAN Session: Configuration: Source and Destination Section

Local SPAN Session: Configuration: Session Settings Section

Table 5-1 Local SPAN Session: Configuration: Session Settings Section 

Element
Description

Session Id

Local SPAN session number that can only be specified when the session is first created. The value ranges from 1 to 18.

Description

Description for this session.

Filtered VLANs

When clicked, list of configured VLANs appears.

Admin Status

Administrative status of the session.

Operational Status

Display only. Whether the session is shut (down) or enabled (up).

Status Description

Display only. Status description.


Local SPAN Session: Configuration: Source and Destination Section

Table 5-2 Local SPAN Session: Configuration: Source and Destination Section 

Element
Description
Source

Interface/VLAN

Display only. Port or VLAN number.

Description

Display only. Port or VLAN description.

Ingress

Status of whether to monitor ingress packets.

Egress

Status of whether to monitor egress packets.

Destination

Interface

Display only. Port number.

Description

Display only. Port description.


Additional References

For additional information related to implementing SPAN, see the following sections:

Related Documents

Standards

Related Documents

Related Topic
Document Title

VDCs

Virtual Device Context Configuration Guide, Cisco DCNM for LAN, Release 5.x


Standards

Standards
Title

No new or modified standards are supported by this feature, and support for existing standards has not been modified by this feature.


Feature History for SPAN

Table 5-3 lists the release history for this feature.

Table 5-3 Feature History for SPAN

Feature Name
Releases
Feature Information

SPAN

5.2(1)

Support was added for the Cisco Nexus 3000 Series switches.

SPAN

5.1(1)

No change from Release 5.0.

SPAN

5.0(2)

No change from Release 4.2.

SPAN

4.2(1)

No change from Release 4.1.