Link Aggregation Control Protocol (Lacp) - Juniper JUNOS OS 10.4 - FOR EX REV 1 Manual

Link Aggregation Control Protocol (LACP)

Copyright © 2010, Juniper Networks, Inc.
The LAG must be configured on both sides of the link.
The interfaces on either side of the link must be set to the same speed.
You can configure and apply firewall filters on a LAG.
LACP can optionally be configured for link negotiation.
You can combine physical Ethernet ports belonging to different member switches of a
Virtual Chassis configuration to form a LAG. See "Understanding EX4200 Virtual Chassis
Link Aggregation" on page 902.
NOTE: The interfaces that are included within a bundle or LAG are sometimes
referred to as member interfaces. Do not confuse this term with member
switches, which refers to Juniper Networks EX4200 Ethernet Switches that
are interconnected as a Virtual Chassis. It is possible to create a LAG that is
composed of member interfaces that are located in different member
switches of a Virtual Chassis.
A LAG creates a single logical point-to-point connection. A typical deployment for a LAG
would be to aggregate trunk links between an access switch and a distribution switch or
customer edge (CE) router.
When LACP is configured, it detects misconfigurations on the local end or the remote
end of the link.
About enabling LACP:
When LACP is not enabled, a local LAG might attempt to transmit packets to a remote
single interface, which causes the communication to fail.
When LACP is enabled, a local LAG cannot transmit packets unless a LAG with LACP
is also configured on the remote end of the link.
By default, Ethernet links do not exchange protocol data units (PDUs), which contain
information about the state of the link. You can configure Ethernet links to actively
transmit PDUs, or you can configure the links to passively transmit them, sending out
LACP PDUs only when they receive them from another link. The transmitting link is known
as the actor and the receiving link is known as the partner.
In a scenario where a dual-homed server is deployed with a switch, the network interface
cards form a LAG with the switch. During a server upgrade, the server may not be able
to exchange LACP PDUs. In such a situation you can configure an interface to be in the
UP state even if no PDUs are exchanged. Use the
interface when the peer has limited LACP capability. The interface selects the associated
LAG by default, whether the switch and peer are both in active or passive mode. When
there are no received PDUs, the partner is considered to be working in the passive mode.
Therefore, LACP PDU transmissions are controlled by the transmitting link.
Chapter 56: Interfaces—Overview
force-up statement to configure an
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