Traffic Monitoring

Traffic Monitoring

Traffic monitoring copies traffic from one or more source ports and sends the copied traffic to a dedicated destination port for analysis by a network analyzer. This feature is also known as Switched Port Analyzer (SPAN).

Types of Traffic Monitoring Sessions

There are two types of monitoring sessions:

  • Ethernet

  • Fibre channel

The type of destination port determines what kind of monitoring session you need. For an Ethernet traffic monitoring session, the destination port must be an unconfigured physical port.

Traffic Monitoring Across Ethernet

An Ethernet traffic monitoring session can monitor any of the following traffic source and destination ports:

Source Ports

Destination Ports

  • Uplink Ethernet port

  • Ethernet port channel

  • VLAN

  • Service profile vNIC

  • Service profile vHBA

  • FCoE port

  • Port channels

  • Unified uplink port

  • VSAN

Unconfigured Ethernet Port


Note

All traffic sources must be located within the same switch as the destination port. A port configured as a destination port cannot also be configured as a source port. A member port of a port channel cannot be configured individually as a source. If the port channel is configured as a source, all member ports are source ports.

A server port can be a source, only if it is a nonvirtualized rack server adapter-facing port.

  • Cisco UCS 6300 Fabric Interconnect supports port-based mirroring.

  • Cisco UCS 6300 Fabric Interconnect supports VLAN SPAN only in the Rx or the receive direction.

  • Ethernet SPAN is port based on the Cisco UCS 6300 Fabric Interconnect.

You can monitor Fibre Channel traffic using either a Fibre Channel traffic analyzer or an Ethernet traffic analyzer. When Fibre Channel traffic is monitored with an Ethernet traffic monitoring session, at an Ethernet destination port, the destination traffic is FCoE.

A Fibre Channel traffic monitoring session can monitor any of the following traffic source and destination ports:

Source Ports

Destination Ports

  • FC Port

  • FC Port Channel

  • Uplink Fibre Channel port

  • SAN port channel

  • VSAN

  • Service profile vHBA

  • Fibre Channel storage port

  • Fibre Channel uplink port

Guidelines and Recommendations for Traffic Monitoring

When configuring or activating traffic monitoring, consider the following guidelines:

Traffic Monitoring Sessions

A traffic monitoring session is disabled by default when created. To begin monitoring traffic, first activate the session. A traffic monitoring session must be unique on any fabric interconnect within the Cisco UCS pod. Create each monitoring session with a unique name and unique VLAN source. To monitor traffic from a server, add all vNICs from the service profile corresponding to the server.

Maximum Number of Supported Active Traffic Monitoring Sessions Per Fabric-Interconnect

You can create and store up to 16 traffic monitoring sessions, but only four can be active at the same time. The receive and transmit directions each count as one monitoring session, while the bi-direction monitoring session is counted as 2. For example:

  • Four active sessions — If each session is configured to monitor traffic in only one direction

  • Two active sessions — If each session is configured to monitor traffic bidirectionally.

  • Three active sessions — If one session is unidirectional and the second session is bidirectional.


Note

Traffic monitoring can impose a significant load on your system resources. To minimize the load, select sources that carry as little unwanted traffic as possible and disable traffic monitoring when it is not needed.

Because a traffic monitoring destination is a single physical port, a traffic monitoring session can monitor only a single fabric. To monitor uninterrupted vNIC traffic across a fabric failover, create two sessions, one per fabric and connect two analyzers. Add the vNIC as the traffic source using the exact same name for both sessions. If you change the port profile of a virtual machine, any associated vNICs being used as source ports are removed from monitoring, and you must reconfigure the monitoring session. If a traffic monitoring session was configured on a dynamic vNIC under a release earlier than Cisco UCS Manager Release 2.0, you must reconfigure the traffic monitoring session after upgrading.

A vHBA can be a source for either an Ethernet or Fibre Channel monitoring session, but it cannot be a source for both simultaneously. When a VHBA is set as the SPAN source, the SPAN destination only receives VN-Tagged frames. It does not receive direct FC frames.

Choosing Between Traffic Monitoring Sessions

From Cisco UCS Manager 4.3(4a), you can now choose between SPAN or ERSPAN traffic monitoring sessions.

Limitations


Note
Existing SPAN limitations apply to ERSPAN too.

The following are the limitations when you choose between SPAN or ERSPAN traffic monitoring sessions:

  • Session migration is not supported. You cannot change the session type from SPAN to ERSPAN or vice versa after it is created.

  • ERSPAN does not share origin interface or VLAN configuration with Netflow.

    You cannot use the same source VLAN for both Netflow and ERSPAN.


    Note
    IP addresses also cannot be shared with Netflow.

  • You cannot enable span capturing control packets on ERSPAN sessions.

Traffic Monitoring for SPAN

Creating an Ethernet Traffic Monitoring Session

Procedure

Step 1

In the Create Traffic Monitoring Session dialog box, complete the following fields:

Name Description

Name field

The name of the traffic monitoring session.

This name can be between 1 and 16 alphanumeric characters. You cannot use spaces or any special characters other than - (hyphen), _ (underscore), : (colon), and . (period), and you cannot change this name after the object is saved.

Admin State field

Indicates whether traffic will be monitored for the physical port selected in the Destination field. This can be one of the following:

  • Enabled—Cisco UCS begins monitoring the port activity as soon as some source components are added to the session.

  • Disabled—Cisco UCS does not monitor the port activity.

Span Control Packets field

Indicates whether outgoing control packets that are sent from the CPU are monitored. This can be one of the following:

  • Enabled—Cisco UCS monitors outgoing control packets on the port.

  • Disabled—Cisco UCS does not monitor outgoing control packets on the port.

Destination drop-down list

The physical port that is being monitored.

Click the link in this field to view the port properties.

Admin Speed field

The data transfer rate of the port channel to be monitored.

The available data rates depend on the fabric interconnect installed in the Cisco UCS domain.

Step 2

Click OK.

What to do next

  • Add traffic sources to the traffic monitoring session.

  • Activate the traffic monitoring session.

Setting the Destination for an Existing Ethernet Traffic Monitoring Session

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

On the LAN tab, expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name > Monitor_Session_Name.

Step 3

In the Work pane, click the General tab.

Step 4

In the Actions area, click Set Destination.

Step 5

In the Set Destination dialog box, complete the following fields:

Example:

Name Description

Destination drop-down list

The physical port where you want to monitor all the communication from the sources.

Admin Speed field

The data transfer rate of the port channel to be monitored.

The available data rates depend on the fabric interconnect installed in the Cisco UCS domain.

Step 6

Click OK.

Clearing the Destination for an Existing Ethernet Traffic Monitoring Session

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

Expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name > Monitor_Session_Name.

Step 3

In the Work pane, click the General tab.

Step 4

In the Actions area, click Clear Destination.

Step 5

If a confirmation dialog box displays, click Yes.

Creating a Fibre Channel Traffic Monitoring Session

Procedure

Step 1

In the Navigation pane, click SAN.

Step 2

ExpandSAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name

Step 3

Right-click Fabric_Interconnect_Name and choose Create Traffic Monitoring Session.

Step 4

In the Create Traffic Monitoring Session dialog box, complete the following fields:

Name Description

Name field

The name of the traffic monitoring session.

This name can be between 1 and 16 alphanumeric characters. You cannot use spaces or any special characters other than - (hyphen), _ (underscore), : (colon), and . (period), and you cannot change this name after the object is saved.

Admin State field

Indicates whether traffic will be monitored for the physical port selected in the Destination field. This can be one of the following:

  • Enabled—Cisco UCS begins monitoring the port activity as soon as some source components are added to the session.

  • Disabled—Cisco UCS does not monitor the port activity.

Span Control Packets field

Indicates whether outgoing control packets that are sent from the CPU are monitored. This can be one of the following:

  • Enabled—Cisco UCS monitors outgoing control packets on the port.

  • Disabled—Cisco UCS does not monitor outgoing control packets on the port.

Destination drop-down list

Select the physical port where you want to monitor all the communication from the sources.

Admin Speed drop-down list

The data transfer rate of the port channel to be monitored. The available data rates depend on the fabric interconnect installed in the Cisco UCS domain. This can be one of the following:

  • 1 Gbps

  • 10 Gbps

  • 25 Gbps

  • Auto—Cisco UCS determines the data transfer rate.

Step 5

Click OK.

What to do next

  • Add traffic sources to the traffic monitoring session.

  • Activate the traffic monitoring session.

Setting the Destination for an Existing Fibre Channel Traffic Monitoring Session

Procedure

Step 1

In the Navigation pane, click SAN.

Step 2

ExpandSAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name > Monitor_Session_Name

Step 3

In the Work pane, click the General tab.

Step 4

In the Actions area, click Set Destination.

Step 5

In the Set Destination dialog box, complete the following fields:

Name Description

Destination drop-down list

Select the physical port where you want to monitor all the communication from the sources.

Admin Speed drop-down list

The data transfer rate of the port channel to be monitored. The available data rates depend on the fabric interconnect installed in the Cisco UCS domain. This can be one of the following:

  • 4G HDFI

    • 1 Gbps

    • 10 Gbps

    • 25GB Gbps

    • Auto

  • 5G

    • 10 Gbps

    • 25 Gbps

    • 40 Gbps

    • 100 Gbps

Step 6

Click OK.

Clearing the Destination for an Existing Fibre Channel Traffic Monitoring Session

Procedure

Step 1

In the Navigation pane, click SAN.

Step 2

Expand SAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name > Monitor_Session_Name

Step 3

In the Work pane, click the General tab.

Step 4

In the Actions area, click Clear Destination.

Step 5

If a confirmation dialog box displays, click Yes.

ERSPAN Truncation

Beginning with Cisco UCS Manager 4.3(4a), you can configure the truncation of source packets for each ERSPAN session based on the size of the maximum transmission unit (MTU). Truncation helps to decrease ERSPAN bandwidth by reducing the size of monitored packets. Any ERSPAN packet that is larger than the configured MTU size is truncated to the given size. For ERSPAN, an additional ERSPAN header is added to the truncated packet from 54 to 166 bytes depending on the ERSPAN header type. For example, if you configure the MTU as 300 bytes, the packets are replicated with an ERSPAN header size from 354 to 466 bytes depending on the ERSPAN header type configuration.

ERSPAN truncation is disabled by default. To use truncation, you must enable it for each ERSPAN session.

Configuring ERSPAN Truncation

You can configure truncation for ERSPAN source sessions only.


Note
By default, the ERSPAN session forwards the entire packets (9216 jumbo packets).

This procedure describes how to truncate the MTU size:

Before you begin

Enable packet truncation for an ERSPAN.

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

Expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name.

Step 3

In the Traffic Monitoring Sessions window, click Add.

Step 4

Choose the ERSPAN Source radio button to configure the ERSPAN source session.

Step 5

Check the Enable Packet Truncation check box to enable packet truncation for an ERSPAN.

Step 6

In the Maximum Transmission Unit field, enter the maximum transmission unit.

Note

 
This field is displayed only when Enable Packet Truncation is enabled. The MTU size range is from 64 to 1518 bytes. The maximum allowed size is 1518 bytes.

Step 7

Click OK.

Viewing or Modifying an ERSPAN Truncation

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

Expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name.

Step 3

Expand Fabric_Interconnect_Name and select the ERSPAN traffic monitor session.

Step 4

In the General tab, under the Properties area, you can view or modify the Maximum Transmission Unit.

Step 5

In the Maximum Transmission Unit field, modify the maximum transmission unit.

Note

 
This field is displayed only when Enable Packet Truncation is enabled. The MTU size range is from 64 to 1518 bytes. The maximum allowed size is 1518 bytes.

Step 6

Click Save Changes to save the configuration change.

Adding Traffic Sources to a Monitoring Session

You can choose multiple sources from more than one source type to be monitored by a traffic monitoring session. The available sources depend on the components configured in the Cisco UCS domain.


Note

This procedure describes how to add sources for Ethernet traffic monitoring sessions. To add sources for a Fibre Channel monitoring session, select the SAN tab instead of the LAN tab in Step 2.

Before you begin

A traffic monitoring session must be created.

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

Expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name.

Step 3

Expand Fabric_Interconnect_Name and click the monitor session that you want to configure.

Step 4

In the Work pane, click the General tab.

Step 5

In the Sources area, expand the section for the type of traffic source that you want to add.

Step 6

To see the components that are available for monitoring, click the + button in the right-hand edge of the table to open the Add Monitoring Session Source dialog box.

Step 7

Select a source component and click OK.

You can repeat the preceding three steps as needed to add multiple sources from multiple source types.

Step 8

Click Save Changes.

What to do next

Activate the traffic monitoring session. If the session is already activated, traffic will be forwarded to the monitoring destination when you add a source.

Activating a Traffic Monitoring Session


Note

This procedure describes how to activate an Ethernet traffic monitoring session. To activate a Fibre Channel monitoring session, select the SAN tab instead of the LAN tab in Step 2.

Before you begin

A traffic monitoring session must be created.

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

Expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name.

Step 3

Expand Fabric_Interconnect_Name and click the monitor session that you want to activate.

Step 4

In the Work pane, click the General tab.

Step 5

In the Properties area, click the enabled radio button for Admin State.

Step 6

Click Save Changes.

If a traffic monitoring source is configured, traffic begins to flow to the traffic monitoring destination port.

Deleting a Traffic Monitoring Session


Note

This procedure describes how to delete an Ethernet traffic monitoring session. To delete a Fibre Channel monitoring session, select the SAN tab instead of the LAN tab in Step 2.

Procedure

Step 1

In the Navigation pane, click LAN.

Step 2

Expand LAN > Traffic Monitoring Sessions > Fabric_Interconnect_Name.

Step 3

Expand Fabric_Interconnect_Name and click the monitor session that you want to delete.

Step 4

In the Work pane, click the General tab.

Step 5

In the Actions area, click the Delete icon.

Step 6

If a confirmation dialog box displays, click Yes.