[asterisk-users] Fully utilise all PRIs in a DAHDI group

[Raj Mathur ( राज माथुर )]

Hi,

Our client has DAHDI groups with 4 PRIs in each group (one 4-port 
interface per group), up to 6 groups per server.  When we dial, we can 
specify the group to be used for dialling, and our dial plan 
automatically distributes calls over multiple servers and multiple 
groups within a server.

The way Asterisk dials by default is to use the lowest-numbered free 
line in a group to place a call.  This is technically fine.  However, 
what it means for our client is that the first couple of PRIs in a group 
tend to get the bulk of calls, the other two remain more-or-less 
unutilised.  This is a problem, since there are call commitments to the 
Telco for each PRI line.  The Telco tends to get all soggy and hard to 
light if some of the PRIs are used way below committed call levels.

One solution is to group at the individual PRI level, so the load 
balancing automatically takes care of fair utilisation of each PRI.  
However, for various reasons we'd prefer not to do this.

Another solution would be if Asterisk could choose a random (or LRU or 
LCU or round-robin or any other scheme) PRI within a group when 
dialling.  Any roughly fair way to distribute calls to PRIs within a 
DAHDI group would be fine.  Is there some way to achieve this?

Asterisk 1.8.8 on Debian Squeeze.

Regards,

-- Raj
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