Lacp; Higher-Level Protocols; Figure 20: Interface Stack For 802.3Ad Link Aggregation - Juniper JUNOSE SOFTWARE FOR E SERIES 11.3.X - LINK LAYER CONFIGURATION GUIDE 2010-10-13 Configuration Manual

JunosE 11.3.x Link Layer Configuration Guide

LACP

Higher-Level Protocols

198
For information about the modules that support link aggregation, see ERX Module Guide,
Appendix A, Module Protocol Support and E120 and E320 Module Guide, Appendix A, IOA
Protocol Support.
The Link Aggregation Control Protocol (LACP) is a mechanism for exchanging port and
system information to create and maintain LAG bundles. The LAG bundle distributes
MAC clients across the link layer interface and collects traffic from the links to present
to the MAC clients of the LAG bundle.
To create the links in the LAG bundles, you can add one or more Ethernet physical
interfaces to it. The LACP detects Ethernet interfaces as links if they are configured on
the same line module and have the same physical layer characteristics. The LACP also
assigns to the LAG bundle the same MAC address of the Ethernet link with the highest
port priority, which is the lowest value.
The LACP also controls the exchange of LACP protocol data units (PDUs) between the
Ethernet links in the LAG bundle. The PDUs contain information about each link and
enable the LAG bundle to maintain them.
By default, Ethernet links do not exchange PDUs, which contain information about the
state of the link. You can configure Ethernet links to actively transmit PDUs, or passively
transmit them, sending out LACP PDUs only when it receives them from another link.
The transmitting link is known as the Actor and the receiving link is known as the Partner.
After you configure the LAG bundle, you can route IP traffic over it, create a VLAN over
it, route PPPoE traffic over it, or route MPLS traffic over it.
Figure 20 on page 198 displays the interface stack for 802.3ad link aggregation.

Figure 20: Interface Stack for 802.3ad Link Aggregation

IP OR VLAN OR
802.3ad Link Agg regation Interf
MA C MA C
Fast Ether net Fast Ether net Fast Ether net
interf ace interf ace
4/0 4/2
LA G b undle
For information about configuring higher-level protocols over VLANs, see "Configuring
VLAN and S-VLAN Subinterfaces" on page 167.
OR
PPP oE
MPLS
ace
MA C MA C
Fast Ether net
interf ace interf ace
4/3 4/5
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