Link Bundle Configuration Overview; Link Switchover; Lacp Fallback - Cisco NCS 5500 Series Configuration Manual

Link Bundle Configuration Overview

Link Bundle Configuration Overview
The following steps provide a general overview of the link bundle configuration. Keep in mind that a link
must be cleared of all previous network layer configuration before it can be added to a bundle:
1 In global configuration mode, create a link bundle. To create an Ethernet link bundle, enter the interface
Bundle-Ether command.
2 Assign an IP address and subnet mask to the virtual interface using the ipv4 address command.
3 Add interfaces to the bundle you created in Step 1 with the bundle id command in the interface configuration
submode.
You can add up to 32 links to a single bundle.
4 You can optionally implement 1:1 link protection for the bundle by setting the bundle maximum-active
links command to 1. Performing this configuration causes the highest-priority link in the bundle to become
active and the second-highest-priority link to become the standby. (The link priority is based on the value
of the bundle port-priority command.) If the active link fails, the standby link immediately becomes the
active link.
A link is configured as a member of a bundle from the interface configuration submode for that link.
Note

Link Switchover

By default, a maximum of 64 links in a bundle can actively carry traffic. If one member link in a bundle fails,
traffic is redirected to the remaining operational member links.
You can optionally implement 1:1 link protection for a bundle by setting the bundle maximum-active links
command to 1. By doing so, you designate one active link and one or more dedicated standby links. If the
active link fails, a switchover occurs and a standby link immediately becomes active, thereby ensuring
uninterrupted traffic.
If the active and standby links are running LACP, you can choose between an IEEE standard-based switchover
(the default) or a faster proprietary optimized switchover. If the active and standby links are not running
LACP, the proprietary optimized switchover option is used.
Regardless of the type of switchover you are using, you can disable the wait-while timer, which expedites the
state negotiations of the standby link and causes a faster switchover from a failed active link to the standby
link.
To do so, you can use the lacp fast-switchover command.

LACP Fallback

The LACP Fallback feature allows an active LACP interface to establish a Link Aggregation Group (LAG)
port-channel before the port-channel receives the Link Aggregation and Control Protocol (LACP) protocol
data units (PDU) from its peer. With the LACP Fallback feature configured, the router allows the server to
bring up the LAG, before receiving any LACP PDUs from the server, and keeps one port active. This allows
the server to establish a connection to PXE server over one Ethernet port, download its boot image and then
Interface and Hardware Component Configuration Guide for Cisco NCS 5500 Series Routers, IOS XR Release
6.1.x
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Configuring Link Bundling