[cisco-voip] Dual PRI Config

[Robert Kulagowski]

CarlosOrtiz at bayviewfinancial.com wrote:
> 
> I usually use MGCP but I am not working at a place that is using H.323 
> on their gateways (been a while for H.323) .  They are adding a second 
> PRI to an office and want to set this up to increase 
> capacity/redundancy.  Is it still typical to use the dial-peer 
> preference command to select the preferred outbound PRI.  Is their 
> another way such as trunk group or soemthing like that?

Here's a snippet from GWGK:

"
Influencing Path Selection > Using Trunk Groups
Using Trunk Groups

BRI, PRI, and CAS interfaces and FXO, FXO, and Ear and Mouth (E&M) voice 
ports can be combined into trunk groups. When you create a trunk group, 
you can add configuration to control path selection. Create a trunk 
group with the global trunk group name command. This puts you in trunk 
group configuration mode. You can then add commands that will apply to 
all the circuits in the group. The max-call voice number command limits 
the number of incoming and outgoing calls that the trunk group will 
accept. By default, the least-used trunk is selected when the gateway 
hunts through a trunk group. You can change this with the hunt-scheme 
command. This command has the following options:

     *

       least-idle [even | odd | both]— Looks for the most recently 
released channel.
     *

       least-used [even | odd | both [up | down]]— Is the default hunt 
method for a trunk group. It looks for the trunk member with the most 
unused channels.
     *

       longest-idle [even | odd | both]— Looks for the trunk member that 
has been idle the longest amount of time.
     *

       Random— Chooses a trunk member at random and a random channel 
within that trunk member.
     *

       round-robin [even | odd | both[up | down]]— Looks at trunk group 
members in a round robin fashion, one after the other.
     *

       sequential [even | odd | both[up | down]]— Always starts looking 
for a free channel with the highest priority trunk.

In each command, even selects even-numbered channels within a trunk 
member first, odd selects odd-numbered channels within a trunk member 
first, and both considers all channels for selection. The option up 
hunts through the channels in ascending order, whereas the option down 
hunts through them in descending order.

Add an interface or voice port to a hunt group with the trunk group name 
[preference] command. The preference value indicates the priority of the 
trunk within the group. A lower preference value equates to a higher 
priority trunk. You can then assign multiple trunk groups to dial peers, 
with a priority value to determine their use by the dial peer.
"

Personally, since I don't don't want to do any fancy load balancing or 
selection, I just use the preference command instead of trunk groups. 
Once one PRI is totally full it'll start using the next one, which is 
fine by me.