Configuring Link-State Tracking

Configuring Link-State Tracking
This chapter describes how to configure link-state tracking on the Cisco Nexus 4000 Series device using
Cisco Data Center Network Manager (DCNM) for LAN.
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.
Note
Link-state tracking is applicable only for the Cisco Nexus 4000 Series platform, beginning with the DCNM
4.2(3) release.
This chapter includes the following sections:
• Information About Link-State Tracking, page 1
• Licensing Requirements for Link-State Tracking, page 3
• Prerequisites for Link-State Tracking, page 3
• Guidelines and Limitations for Link-State Tracking, page 4
• Platform Support for Link State Tracking, page 4
• Configuring Link-State Tracking, page 5
• Exporting Link-State Information to Excel, page 8
• Field Descriptions for Link-State Tracking, page 8
• Link-State Additional References, page 10
• Feature History for Configuring Link-State Tracking, page 10
Information About Link-State Tracking
Link-state tracking, also known as trunk failover, is a feature that binds the link state of multiple interfaces
to create redundancy in the network. The feature provides redundancy in the network when used with server
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Information About Link-State Tracking
network interface card (NIC) adapter teaming. When the server network adapters are configured in a primary
or secondary relationship known as teaming and the link is lost on the primary interface, connectivity
transparently changes to the secondary interface.
The following figure shows a network configured with link-state tracking. After you enable link-state tracking
and create a link-state group, you assign interfaces to the link-state group. Interfaces connected to servers are
referred to as downstream interfaces, and interfaces connected to distribution switches and network devices
are referred to as upstream interfaces.
When link-state tracking is enabled, the downstream interfaces are bound to the upstream interfaces. After a
set of downstream ports are associated to a set of upstream ports, if all of the upstream ports become unavailable,
link-state tracking automatically puts the associated downstream ports in an error-disabled state, which causes
the primary interface of the server to fail over to the secondary interface.
Figure 1: Typical Link-State Tracking Configuration
The configuration in the preceding figure ensures that when server NIC adapter teaming is used, the traffic
flow continues uninterrupted when the uplink connection to a distribution switch is lost. The configuration is
as follows:
• The blade switches in the enclosure are connected to switch 1 and switch 2 through different switches.
• Link-state group 1 is the primary link from all the blade servers in the enclosure (blade server 1 through
blade server n) to switch 1.
• Link-state group 2 is the secondary (backup) link from all the blade servers to switch 2.
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Licensing Requirements for Link-State Tracking
In a link-state group, the upstream ports can become unavailable or lose connectivity because the switch or
router fails, the cables are disconnected, or the link is lost. These interactions occur between the downstream
and upstream interfaces when link-state tracking is enabled:
• If any of the upstream interfaces are in the link-up state, the downstream interfaces can change to or
remain in the link-up state.
• If the server detects that the primary link is down, it redirects the traffic to the secondary (backup) link
and the secondary link becomes the primary link.
As an example of a connectivity change from link-state group 1 to link-state group 2, when the primary link
from blade switch 1 to switch 1 is lost, blade server 1 connects through its secondary Ethernet server interface
to blade switch 2 in link-state group 2.
When link-state tracking is disabled, the entire feature is disabled. All the configuration for link-state tracking
is removed. The downstream ports revert back to the state when no link-state tracking was set.
You can recover a downstream interface link-down condition by removing the failed downstream port from
the link-state group. To recover for multiple downstream interfaces, disable the link-state group.
Licensing Requirements for Link-State Tracking
The following table shows the licensing requirements for this feature:
Product
License Requirement
Cisco DCNM
Link-state tracking requires no license. Any feature
not included in a license package is bundled with the
Cisco DCNM and is provided at no charge to you.
Cisco NX-OS
Link-state tracking requires an Enterprise Services
license. For a complete explanation of the Cisco
NX-OS licensing scheme and how to obtain and apply
licenses, see the Cisco Nexus 7000 Series NX-OS
Licensing Guide, Release 4.2.
Prerequisites for Link-State Tracking
Link-state tracking requires that you configure the logging level in any switch that is used for this feature.
The proper logging level ensures that DCNM is synchronized with the link-state tracking status.
To set the proper logging level, enter the following commands:
logging logfile messages 6
logging level lstsvc 4
Note
The logging level lstsvc 4 command can only be used after link-state tracking has been enabled in the
switch. Whenever you enable link-state tracking, you must configure these logging-level commands to
ensure that DCNM is in sync with the switch for link-state tracking management.
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Guidelines and Limitations for Link-State Tracking
Guidelines and Limitations for Link-State Tracking
Link-state tracking has the following guidelines and limitations:
• Ethernet 1/1–14 are the designated downstream interfaces.
• Ethernet 1/15–20 are the designated up stream interfaces.
Note
The Cisco Nexus 4000 Series switch module allows a user to configure a downstream interface as an
upstream interface or an upstream interface as a downstream interface. Even though this configuration is
allowed in the switch, it is not a valid configuration.
Any attempt to configure an upstream interface as downstream, or a downstream interface as upstream,
generates an exception and DCNM displays a warning message. However, DCNM does not prevent a
user from proceeding with the incorrect configuration.
Platform Support for Link State Tracking
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 4000 Series switches
Cisco Nexus 4000 Series switch documentation
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Configuring Link-State Tracking
Configuring Link-State Tracking
You can access Link-State Tracking from the Switching feature selection. This figure shows how to configure
link-state tracking.
Figure 2: Configuring Link-State Tracking
For more information about the Cisco DCNM features, see the Cisco DCNM Fundamentals Guide, Release
5.x.
Enabling Link-State Tracking
You must enable the link-state tracking feature before you can configure any link-state groups.
Procedure
Step 1
From the Feature Selector pane, choose Switching > Link-State Tracking.
The available devices appear in the Summary pane.
Step 2
Step 3
From the Summary pane, click the device on which you want to enable link-state tracking.
From the Details pane, click Enable Link-State Tracking.
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Creating a Link-State Group
What to Do Next
Creating a Link-State Group, on page 6
Assigning Interfaces to a Link-State Group, on page 6
Removing Interfaces from a Link-State Group, on page 7
Deleting a Link-State Group, on page 7
Creating a Link-State Group
You can create one or more link-state groups and then assign interfaces to the groups.
Before You Begin
Ensure that you have enabled the link-state tracking feature.
Procedure
Step 1
From the Feature Selector pane, choose Switching > Link-State Tracking.
The available devices appear in the Summary pane.
Step 2
From the Summary pane, right-click the device and choose New Group.
A new row of blank fields appear below the device.
Step 3
Enter a numerical name for the new group, from 1 to 6, and then press Enter.
Note
If you attempt to enter a name other than a number from 1 to 6, the group field is removed and you
must repeat Step 2.
Blank tables for Upstream Interfaces and Downstream Interfaces display in the Details pane.
Assigning Interfaces to a Link-State Group
You can assign a device’s ports as upstream or downstream interfaces in a link-state group.
Before You Begin
Ensure that you have enabled the link-state tracking feature and created at least one link-state group.
Procedure
Step 1
Step 2
Step 3
From the Feature Selector pane, choose Switching > Link-State Tracking.
In the Summary pane, click a link-state group to highlight it.
In the Details pane, right-click within the Upstream Interfaces or Downstream Interfaces pane and, from
the drop-down list, choose Add Interfaces.
A dialog box appears, showing the ports that are available to be assigned to this link-state group.
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Removing Interfaces from a Link-State Group
Step 4
Step 5
From the Available Ports pane, choose a port to assign to the link-state group. If you want to choose more
than one port, press and hold Shift or Ctrl when you click.
Click Add to move the selected port(s) to the Selected Ports pane. Click OK to assign the selected ports. To
assign all the available ports to the link-state group, click Add All.
The dialog box closes and the selected ports appear in the Upstream Interfaces or Downstream Interfaces
table.
Removing Interfaces from a Link-State Group
You can remove ports that have been assigned to an upstream or downstream interface in a link-state group.
Before You Begin
Ensure that you have enabled the link-state tracking feature, created at least one link-state group, and assigned
interfaces to the group.
Procedure
Step 1
Step 2
From the Feature Selector pane, choose Switching > Link-State Tracking.
In the Summary pane, click a link-state group to highlight it.
The upstream and downstream interfaces that have been assigned to this link-state group appear.
Step 3
In the Details pane, click one of the ports in the Upstream Interfaces or Downstream Interfaces table and press
Delete. If you want to choose more than one port, press and hold Shift or Ctrl when you click.
The selected port(s) are removed from the table.
Deleting a Link-State Group
You can delete link-state groups. When you delete a link-state group, any interfaces that were assigned to that
group become available and can be assigned to another group.
Procedure
Step 1
From the Feature Selector pane, choose Switching > Link-State Tracking.
The available devices appear in the Summary pane.
Step 2
Step 3
From the Summary pane, right-click the link-state group that you want to delete.
From the drop-down list, choose Delete Link-State Group.
The link-state group is removed from the Summary pane.
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Exporting Link-State Information to Excel
What to Do Next
Enabling Link-State Tracking, on page 5
Creating a Link-State Group, on page 6
Assigning Interfaces to a Link-State Group, on page 6
Removing Interfaces from a Link-State Group, on page 7
Exporting Link-State Information to Excel
You can export details about link-state groups to an Excel file (.xls). The information displays in the Excel
file similar to the arrangement in the Summary pane, showing the link-state group names, upstream and
downstream interfaces, and events.
Procedure
Step 1
From the Feature Selector pane, choose Switching > Link-State Tracking.
The available devices appear in the Summary pane.
Step 2
Above the Summary pane, click the green arrow.
The Export to Excel dialog box displays.
Step 3
Step 4
Navigate to the location where you want to save the file.
Enter a name for the file and click Save.
The file is saved to the specified location.
Field Descriptions for Link-State Tracking
This section includes the following field descriptions for tunnel interfaces:
Link-State Summary Pane
Note
All fields described in the following table are display only.
Table 1: Summary Pane
Field
Description
Link-State Group
Names of devices and the link-state groups within
them.
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Link-State Group: Details Tab
Field
Description
Interfaces
Subdivided into Upstream and Downstream and lists
the specific interfaces assigned to this link-state
group.
Upstream Status
Status of whether the upstream switch is up or down.
The upstream status is up if at least one upstream
interface in that link-state group is up. When all the
upstream interfaces in that group are down, this status
is down.
Events
Cisco DCNM displays a bell icon in the Event column
when an event occurs, such as all upstream interfaces
in the group going down. If the icon appears, you can
click the Event tab to get more details about the event.
Link-State Group: Details Tab
Note
All fields described in the following tables are display only.
Table 2: Link-State Group: Details—Upstream Interface
Field
Description
Name
Name of the port.
Status
Status of whether the port is up or down.
Description
Description of the interface.
Table 3: Link-State Group: Details—Downstream Interface
Field
Description
Name
Name of the port.
Status
Status of whether the port is up or down.
Description
Description of the interface.
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Link-State Additional References
Link-State Additional References
For additional information related to implementing link-state tracking, see the following sections:
Link-State Related Documents
Related Topic
Document Title
Link-state tracking configuration
Cisco Nexus 4001I and 4005I Switch Module for IBM
BladeCenter NX-OS Configuration Guide
Link-state tracking CLI commands
Cisco Nexus 4001I and 4005I Switch Module for IBM
BladeCenter NX-OS Command Reference
Link-State 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 Configuring Link-State Tracking
This table lists the release history for this feature.
Table 4: Feature History for Configuring Link-State Tracking
Feature Name
Releases
Feature Information
Link-State Tracking
4.2(3)
This feature was introduced.
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