Extreme Networks ExtremeWare XOS 11.3, Manual

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Configuring Slots and Ports on a Switch
ExtremeWare XOS 11.3 Concepts Guide
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sharing links because the IP check sum includes the packet length, which is likely to change from
packet to packet.
NOTE
Those variables with CHK_SUM apply only to IPv4 packets.
This feature is available only for the address-based load-sharing algorithm. The selected address-based
algorithm is applied to the entire switch, to all the load-sharing groups configured as address-based.
Layer 2 is the default setting.
The master port of the load-sharing group can be the monitor port for port-mirroring.
LACP—Dynamic Link Aggregation
Beginning with ExtremeWare XOS version 11.3, you can run the Link Aggregation Control Protocol
(LACP) on Extreme Networks devices. LACP enables dynamic load sharing and hot standby for link
aggregation links, in accordance with the IEEE 802.3ad standard. All third-party devices supporting
LACP run with Extreme Networks devices.
The addition of LACP provides the following enhancements to static load sharing, or link aggregation:
●
Automatic configuration
●
Rapid configuration and reconfiguration
●
Deterministic behavior
●
Low risk of duplication or misordering
Once you enable load-sharing, the LACP protocol is enabled by default. You configure dynamic link
aggregation by first assigning a primary, or logical, port to the group, or LAG and then specifying the
other ports you want in the LAG.
LACP, using an automatically generated key, determines which links can aggregate. Each link can
belong to only
one LAG. LACP determines which links are available. The communicating systems
negotiate priority for controlling the actions of the entire trunk (LAG), using LACP, based on the lowest
system MAC number. You can override this automatic prioritization by configuring the system priority
for each LAG.
Once you enable and configure LACP, the system sends PDUs (LACPDUs) on the LAG ports. The
LACPDUs inform the remote system of the identity of the sending system, the automatically generated
key of the link, and the desired aggregation capabilities of the link. If a key from a particular system on
a given link matches a key from that system on another link, those links are aggregatable. Once the
remote system exchanges LACPDUs with the LAG, the system determines the status of the ports and
whether to send traffic on which ports.
Among those ports deemed aggregatable by LACP, the system uses those ports with the lowest port
number as active ports; the remaining ports aggregatable to that LAG are put into standby status.
Should an active link fail, the standby ports become active, also according to the lowest port number.
(See
“Configuring LACP” on page 124 for the number of active and standby LACP links supported per
platform.)