The "ERROR: could not add peer" error message is displayed on the IOS voice gateway when an attempt is made to add a dial peer to an existing dial-peer configuration.

[TCC_2]

Core Issue

How the dial peers are configured depends on the memory available on the router. Each dial peer requires approximately 6 KB of memory. However, if the MAX-DN is set to a high value, there is less space available to accommodate the dial peer. This is because the memory is reserved for that number of Directory Numbers (DNs).  You can configure as many dial-peers as long as you dont use over 80% of the memory. So you must always have 20% memory free or it wont allow more dial-peers.

Resolution

In order to resolve this issue, perform these steps:

1. Issue the show run command in order to verify the Max-DN value.
   
   
2. Reduce the Max-DN value to a value that creates room for more dial peers to be added to the configuration.

For more information refer to the article How to determine the maximum number of dial-peers that can be configured on a router

[paolo bevilacqua]

This problem is actually caused by a memory leak type of bug in many version of IOS.

Proof is that on an affected version, ephone-dn can be added just after a reboot, but not subsequently.

On images without the bug, ephone-dn can be added at any time.

[Muzzamil Hussain]

Actually i faced the same issue with one of our VG 3845 and we added more memory and upgraded the IOS and it worked FINE

[shiblyibrahim]

Paolo what if we increase the memory on the router, would this issue be resolved. When you mean memory I think its RAM right?