Link Aggregation Control Protocol - Lenovo RackSwitch G8264 Application Manual

Link Aggregation Control Protocol

180
G8264 Application Guide for ENOS 8.4
Link Aggregation Control Protocol (LACP) is an IEEE 802.3ad standard for
grouping several physical ports into one logical port (known as a Link
Aggregation group) with any device that supports the standard. Please refer to
IEEE 802.3ad‐2002 for a full description of the standard.
The 802.3ad standard allows standard Ethernet links to form a single Layer 2 link
using Link Aggregation Control Protocol (LACP). Link aggregation is a method of
grouping physical link segments of the same media type and speed in full duplex,
and treating them as if they were part of a single, logical link segment. If a link in
an LACP LAG fails, traffic is reassigned dynamically to the remaining link(s) of the
dynamic LAG.
Note: LACP implementation in the Lenovo Enterprise Network Operating System
does not support the Churn machine, an option used to detect if the port is
operable within a bounded time period between the actor and the partner. Only the
Marker Responder is implemented, and there is no marker protocol generator.
A port's Link Aggregation Identifier (LAG ID) determines how the port can be
aggregated. The Link Aggregation ID (LAG ID) is constructed mainly from the
partner switch's system ID and the port's admin key, as follows:
 System ID: an integer value based on the partner switch's MAC address and the
system priority assigned in the CLI.
 Admin key: a port's Admin key is an integer value (1‐65535) that you can
configure in the CLI. Each switch port that participates in the same LACP LAG
must have the same admin key value. The Admin key is local significant, which
means the partner switch does not need to use the same Admin key value.
For example, consider two switches, an Actor (the G8264) and a Partner (another
switch), as shown in Table
Table 16.
Actor vs. Partner LACP configuration
Actor Switch
Port 7 (admin key = 100)
Port 8 (admin key = 100)
Port 9 (admin key = 100)
Port 10 (admin key = 100) Port 4 (admin key = 70)
In the configuration shown in Table
form an LACP LAG with Partner switch ports 1 and 2. Only ports with the same
LAG ID are aggregated in the LAG. Actor switch ports 9 and 10 are not aggregated
in the same LAG, because although they have the same admin key on the Actor
switch, their LAG IDs are different (due to a different Partner switch admin key
configuration). Instead, they form a secondary LAG with Partner switch ports 3
and 4.
To avoid the Actor switch ports (with the same admin key) from aggregating in
another LAG, you can configure a group ID. Ports with the same admin key
(although with different LAG IDs) compete to get aggregated in a LAG. The LAG
16.
Partner Switch
Port 1 (admin key = 50)
Port 2 (admin key = 50)
Port 3 (admin key = 70)
16, Actor switch ports 7 and 8 aggregate to
LACP LAG
Primary LAG
Primary LAG
Secondary LAG
Secondary LAG