Targeted Traffic Distribution on Aggregated Ethernet Interfaces in a Virtual Chassis
By default, member routers or switches in an EX9200 or MX Series Virtual Chassis use hash-based traffic distribution for subscriber interfaces in aggregated Ethernet bundles configured without link protection. The hash-based model distributes subscriber interface traffic over multiple links in the bundle, enabling you to load balance multiple traffic flows through the logical subscriber interface.
Starting in Junos OS Release 13.2, as an alternative to using hash-based distribution in an EX9200 or MX Series Virtual Chassis, you can configure targeted traffic distribution for IP demultiplexing (demux) or VLAN demux subscriber interfaces in an aggregated Ethernet bundle that is configured without link protection.
Targeted Distribution in a Virtual Chassis
Targeted distribution enables you to configure the Virtual Chassis to send (target) all egress data traffic for a logical subscriber interface across a single member link in an aggregated Ethernet bundle, also referred to as an IEEE 802.3ad link aggregation group (LAG) bundle. You configure targeted distribution for a demux subscriber interface on the Virtual Chassis primary router or switch.
With targeted distribution, the router or switch in a Virtual Chassis assigns the primary member link and backup member link for the aggregated Ethernet bundle across all Virtual Chassis port links that belong to the aggregated Ethernet bundle. To accomplish load balancing, the router or switch evenly distributes the demux subscriber interfaces over these member links.
Benefits of Targeted Distribution
Targeted distribution is especially useful in a Virtual Chassis configuration in which subscriber traffic enters through a Virtual Chassis port on one member router or switch and exits through a Virtual Chassis port on a different member router or switch. By combining Virtual Chassis ports from different member router or switches as member links of the aggregated Ethernet bundle, targeted distribution provides increased redundancy in the event of a chassis or link failure.