Hi. I have a PBX connected to the Cisco 3825 router via one PRI line (I have one VWIC2-1MFT-T1/E1and one PVDM2-64 there) and there is a need to add another PRI link from the same PBX because one line is already not enough. This router acts as a VOIP gateway and we use g729r8 for the most of the calls. There is also another router which is a backup to the main 3825. Here are the solutions that I can see:
1. Add one more VWIC2-1MFT-T1/E1 and one more PVDM2-64 card to the main 3825 router and unite them in one trunk group. So I will double my resources but if the main router fails I will lose all my VOIP connectivity.
2. Add one VWIC2-1MFT-T1/E1 and one PVDM2-64 card to the backup 3825 router. I know it is possible to aggregate several gateways into one route group by means of CUCM , the problem is we haven't one (though I'm trying to figure out a cost of the CUCM solution and required licenses). My question is if it is possible to achieve the desired redundant setup without CUCM?