MC LAG groups overview
Overview
A link aggregation group, or LAG, is a group of physical ports that form one logical link between two NEs to increase bandwidth, allow load balancing, and provide seamless redundancy. LAG support over multiple devices provides NE-level redundancy in addition to link-layer redundancy using a switchover function. An MC LAG configuration provides redundant L2 access connectivity that extends beyond link-layer protection by allowing two devices to share a common LAG endpoint.
An MC LAG configuration includes one active member NE and one standby member NE. The active and standby NEs synchronize the link state information to facilitate link-layer messaging between an access node and each NE. The active and standby NE coupling provides a synchronized forwarding plane to and from the access node. LACP is used to manage the active and standby states of the available LAG links; only the links of one member NE are active at one time.
The following NEs support the creation of MC LAG groups using Ethernet ports in Access mode.
Support for MC LAGs on the 7210 SAS and 7705 SAR varies depending on the chassis type and release; see the NE documentation for support information.
The 7705 SAR-8, 7705 SAR-18, and 7705 SAR-M support the creation of MC LAG groups to provide NE-level redundancy. The operator has the option of creating an alternative path for deploying a service on the redundant NEs. The 7705 SAR NEs support inter-chassis backup, or ICB, on MC LAG to provide redundant Epipe service paths.
Some OmniSwitch NEs also support NE redundancy using MC LAGs; see MC AOS groups in this section.
When you use the NFM-P to change the MC LAG configuration on an NE, the NFM-P automatically updates the MC LAG configuration on the other NE. When you change the MC LAG configuration on an NE using, for example, a CLI, the NFM-P detects the configuration mismatch between the NEs and raises an alarm. The alarm information includes the type of configuration mismatch.
You can create an MC LAG group only from within an existing MC peer group. When only one peer in an MC peer group is managed by the NFM-P, you can configure NE redundancy parameters only for the managed peer, and only from the NE properties form. See Chapter 40, MC peer groups for information about MC peer groups.
MC synchronization
When subscriber management is enabled on an NE in an MC LAG configuration, the NE maintains dynamic state information for each subscriber host. The active and standby NEs synchronize the information to ensure uninterrupted service delivery in the case of an MC LAG switchover. See Chapter 44, MC synchronization groups for information about MC synchronization.
MC AOS groups
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CAUTION Service Disruption |
You must not run an Ethernet OAM or SAA test on an OmniSwitch that has an MC LAG
configuration.
MC AOS groups enable MC LAG creation on OS 9700E and OS 9800E NEs at Release 6.4.5 or later that are equipped with XNI-U12E cards, and on Release 7.3.1 and later OS 6900 and OS 10K NEs.