Juniper JUNOS 10.1 - CONFIGURATION GUIDE 1-2010 Configuration Manual page 730

JUNOS 10.1 Network Interfaces Configuration Guide
connected, so that the traffic flows through the same DPI devices in both directions.
To make sure this happens, you need to also configure the counterpart ports (ports
that are connected to same DPI-iN) with the identical link index. This is done when
configuring a child-link into the LAG bundle. This ensures that the link chosen for a
given hash result is always the same on either router.
Note that any two links connected to each other should have the same link index
and these link indices must be unique in a given bundle.
NOTE:
The following restrictions apply when configuring symmetric load balancing on an
802.3ad LAG on MX Series routers:
For additional information, see the JUNOS VPNs Configuration Guide and the JUNOS
System Basics Configuration Guide.
To configure 802.3ad LAG parameters at the bundle level:
Example Configuration
Statements
where the
You can check the link index configured above using the
660
Configuring Symmetrical Load Balancing on an 802.3ad Link Aggregation Group on MX Series Routers
The Packet Forwarding Engine (PFE) can be configured to hash the traffic in
either symmetric or complement mode. A single PFE complex cannot work
simultaneously in both operational modes and such a configuration can yield
undesirable results.
The per-PFE setting overrides the chassis-wide setting only for the family
configured. For the other families, the PFE complex still inherits the chassis-wide
setting (when configured) or the default setting.
Any change in the hash key configuration requires a reboot of the FPC for the
changes to take effect.
This feature supports VPLS, INET, and bridged traffic only.
This feature cannot work in tandem with the
option. It requires that all the PFE complexes configured in complementary
fashion share the same seed. A change in the seed between two counterpart PFE
complexes may yield undesired results.
[edit interfaces]
g(x)e-fpc/pic/port {
gigether-options {
802.3ad {
bundle;
link-index number;
}
}
}
link-index number
[edit forwarding-options hash-key]
family inet {
per-flow-hash-seed load-balancing
ranges from 0 through 15.
command:
show interfaces