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Link Protection of Aggregated Ethernet Interfaces

 

This topic provides information about how to provide link protection for aggregated Ethernet Interfaces and how to configure the minimum number of links in an aggregated Ethernet interfaces bundle.

You can configure link protection for aggregated Ethernet interfaces to provide QoS on the links during operation.

On aggregated Ethernet interfaces, you designate a primary and backup link to support link protection. Egress traffic passes only through the designated primary link. This includes transit traffic and locally generated traffic on the router or switch. When the primary link fails, traffic is routed through the backup link. Because some traffic loss is unavoidable, egress traffic is not automatically routed back to the primary link when the primary link is reestablished. Instead, you manually control when traffic should be diverted back to the primary link from the designated backup link.

Note

Link protection is not supported on MX80.

Aggregated Ethernet interfaces support link protection to ensure QoS on the interface.

To configure link protection:

  1. Specify that you want to configure the options for an aggregated Ethernet interface.
  2. Configure the link protection mode.

To configure link protection, you must specify a primary and a secondary, or backup, link.

To configure a primary link and a backup link:

  1. Configure the primary logical interface.
  2. Configure the backup logical interface.

See also

On aggregated Ethernet interfaces, you designate a primary and backup link to support link protection. Egress traffic passes only through the designated primary link. This includes transit traffic and locally generated traffic on the router or switch. When the primary link fails, traffic is routed through the backup link. Because some traffic loss is unavoidable, egress traffic is not automatically routed back to the primary link when the primary link is reestablished. Instead, you manually control when traffic should be diverted back to the primary link from the designated backup link.

To manually control when traffic should be diverted back to the primary link from the designated backup link, enter the following operational command:

To disable link protection, issue the delete interface revert aex configuration command.

On aggregated Ethernet interfaces, you can configure the minimum number of links that must be up for the bundle as a whole to be labeled up. By default, only one link must be up for the bundle to be labeled up.

To configure the minimum number of links:

  1. Specify that you want to configure the aggregated Ethernet options.
  2. Configure the minimum number of links.

On M120, M320, MX Series, T Series, and TX Matrix routers with Ethernet interfaces, and EX 9200 switches, the valid range for minimum-links number is 1 through 16. When the maximum value (16) is specified, all configured links of a bundle must be up for the bundle to be labeled up.

On all other routers and on EX Series switches, other than EX8200 switches, the range of valid values for minimum-links number is 1 through 8. When the maximum value (8) is specified, all configured links of a bundle must be up for the bundle to be labeled up.

On EX8200 switches, the range of valid values for minimum-links number is 1 through 12. When the maximum value (12) is specified, all configured links of a bundle must be up for the bundle to be labeled up.

On MX Series routers, when Link Aggregation Control Protocol (LACP) is enabled on a link aggregation group (LAG) interface along with minimum links configuration, the bundle is considered to be up when the following two conditions are met:

  • The specified minimum number of links are up.

  • The links are in collecting distributing state–that is, collecting and distributing states are merged together to form a combined state (coupled control) for the aggregated port. Because independent control is not possible, the coupled control state machine does not wait for the partner to signal that collection has started before enabling both collection and distribution.

If the number of links configured in an aggregated Ethernet interface is less than the minimum link value configured under the aggregated-ether-options statement, the configuration commit fails and an error message is displayed.

The following configuration enables link protection on the ae0 interface, and specifies the ge-1/0/0 interface as the primary link and ge-1/0/1 as the secondary link.