Configuring The Maximum Sessions Per Tunnel; Configuring The Weighted Load Balancing Method - Juniper JUNOSE SOFTWARE 11.0.X - BROADBAND ACCESS CONFIGURATION GUIDE 4-1-2010 Configuration Manual

JUNOSe 11.0.x Broadband Access Configuration Guide
When the router attempts to connect to the domain, suppose it randomly selects
tunnel B from preference 0. If it fails to connect to tunnel B, the router excludes
tunnel B for five minutes and attempts to connect to tunnel A. If this attempt also
fails, the router drops to preference 1. Then suppose the router selects tunnel C. If
it also fails to connect to tunnel C, the router excludes tunnel C for five minutes and
attempts to connect to tunnel D.

Configuring the Maximum Sessions per Tunnel

You can configure the maximum number of sessions per tunnel, either through a
RADIUS server or the command-line interface. If you set the maximum sessions per
tunnel parameter, the router takes the setting into consideration when it selects a
tunnel. If a randomly selected tunnel has a current session count equal to its
maximum session count, the router does not attempt to contact that tunnel. Instead,
it makes an alternate tunnel selection from the set of reachable tunnels at the same
preference level. If no additional reachable tunnels exist at the current preference
level, the router drops to the next lower preference level to make the next selection.
This process is consistent, regardless of which fail-over scheme is currently running
on the router. A tunnel without a configured maximum sessions value has no upper
limit on the number of sessions it can support.
The router uses a default value of 0 (zero), which allows unlimited sessions in the
tunnel.

Configuring the Weighted Load Balancing Method

With the weighted load-balancing method, the router uses the maximum sessions
per tunnel to choose among multiple tunnels that share the same preference level.
The weight of a tunnel is proportional to its maximum session limit and the maximum
session limits of the other tunnels at the same preference level. The tunnel with the
largest maximum session value has the largest weight; the tunnel with the next largest
maximum session value has the next largest weight, down to the tunnel with the
smallest maximum session value that has the smallest weight. The router uses a
round-robin tunnel selection method by default.
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Configuring the Maximum Sessions per Tunnel
A and B at preference 0
C and D at preference 1
To enable tunnel selection failover within a preference level:
host1(config)#l2tp fail-over-within-preference
To configure the maximum sessions per tunnel.
host1(config)#aaa domain-map lacOne
host1(config-domain-map)#tunnel 1
host1(config-domain-map-tunnel)#max-sessions 1500
To configure the router to base tunnel selection within a preference level on the
maximum sessions per tunnel.