Link Bundling Overview
The Link Bundling feature allows you to group multiple point-to-point links together into one logical link and provide higher bidirectional bandwidth, redundancy, and load balancing between two routers. A virtual interface is assigned to the bundled link. The component links can be dynamically added and deleted from the virtual interface.
The virtual interface is treated as a single interface on which one can configure an IP address and other software features used by the link bundle. Packets sent to the link bundle are forwarded to one of the links in the bundle.
A link bundle is simply a group of ports that are bundled together and act as a single link. The advantages of link bundles are as follows:
Multiple links can span several line cards to form a single interface. Thus, the failure of a single link does not cause a loss of connectivity.
Bundled interfaces increase bandwidth availability, because traffic is forwarded over all available members of the bundle. Therefore, traffic can flow on the available links if one of the links within a bundle fails. Bandwidth can be added without interrupting packet flow..
All the individual links within a single bundle must be of the same type and the same speed.
Cisco IOS XR software supports these methods of forming bundles of Ethernet interfaces:
IEEE 802.3ad—Standard technology that employs a Link Aggregation Control Protocol (LACP) to ensure that all the member links in a bundle are compatible. Links that are incompatible or have failed are automatically removed from a bundle.
EtherChannel —Cisco proprietary technology that allows the user to configure links to join a bundle, but has no mechanisms to check whether the links in a bundle are compatible.