Characteristics of Link Bundles
This list describes the properties and limitations of link bundles:
• Any type of Ethernet interfaces can be bundled, with or without the use of LACP (Link Aggregation
Control Protocol).
• Bundle membership can span across several line cards that are installed in a single router.
• A single bundle supports maximum of 64 physical links.
• Different link speeds are allowed within a single bundle, with a maximum of four times the speed
difference between the members of the bundle.
• 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 Ethernet 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 (the distribution of data between member links) 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 and HDLC keepalives, work independently on each link within a
bundle.
• Upper layer protocols, such as routing updates and hellos, 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.
• All links within a single bundle must be configured either to run 802.3ad (LACP) or Etherchannel
(non-LACP). Mixed links within a single bundle are not supported.
• A bundle interface can contain physical links and VLAN subinterfaces only.
• 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.
L2VPN and Ethernet Services Configuration Guide for Cisco ASR 9000 Series Routers, IOS XR Release 6.3.x
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Configuring Link Bundles
Characteristics of Link Bundles