References for configuring link bundles

Use these reference topics to review factual information about configuring link bundles.

Ethernet link bundles provide a set of features and behaviors that enhance network flexibility and manageability. Key characteristics include:

• Any type of Ethernet interfaces can be bundled, with or without the use of LACP (Link Aggregation Control Protocol).

• Physical layer and link layer configuration are performed on individual member links of a bundle.

• Configuration of network layer protocols and higher layer applications is performed on the bundle itself.

• A bundle can be administratively enabled or disabled.

• Each individual link within a bundle can be administratively enabled or disabled.

• Ethernet link bundles are created in the same way as Etherokinet channels, where the user enters the same configuration on both end systems.

• The MAC address that is set on the bundle becomes the MAC address of the links within that bundle.

• When LACP configured, each link within a bundle can be configured to allow different keepalive periods on different members.

• Load balancing is done by flow instead of by packet. Data is distributed to a link in proportion to the bandwidth of the link in relation to its bundle.

• QoS is supported and is applied proportionally on each bundle member.

• Link layer protocols, such as CDP, work independently on each link within a bundle.

• Upper layer protocols, such as routing updates and hello messages, are sent over any member link of an interface bundle.

• Bundled interfaces are point to point.

• A link must be in the UP state before it can be in distributing state in a bundle.

• Access Control List (ACL) configuration on link bundles is identical to ACL configuration on regular interfaces.

• Multicast traffic is load balanced over the members of a bundle. For a given flow, internal processes select the member link and all traffic for that flow is sent over that member.

IEEE 802.3ad (LACP)

Cisco IOS-XR software supports multiple bundle configuration modes to aggregate Ethernet interfaces for improved bandwidth and resiliency. The two primary methods are IEEE 802.3ad (LACP) and Cisco EtherChannel.

• Standard technology for Ethernet aggregation.

• Employs Link Aggregation Control Protocol (LACP) to ensure compatibility among member links.

• Automatically removes incompatible or failed links from the bundle.

Each bundle member exchanges these information between router systems:

• A globally unique local system identifier (usually a MAC address).

• An operational key identifying the bundle.

• A port ID for the link.

• The current aggregation status.

• Member links sharing a common Link Aggregation Group (LAG) ID can be aggregated. Each link has a unique LAG ID.

• System and bundle identifiers must be unique per router.

• Peer system information determines link compatibility.

• Bundle MAC addresses are assigned from reserved sets and persist for the life of the bundle, used by all member links for traffic. Unicast or multicast addresses configured on the bundle are propagated to all member links.

• Cisco proprietary aggregation technology.

• Allows manual link configuration into bundles.

• Does not perform compatibility checks between bundled links.