[Asterisk-Users] Codec ordering?

[Rich Adamson]

Need a little help understanding iax codec ordering....

Asterisk A (v1.07) -> iax2 -> Asterisk B (cvs-head, current)

If both are configured with (I've purposefully left out other statements
that don't pertain to the question):

Type=user
disallow=all
allow=ilbc,gsm

Type=peer
disallow=all
allow=ilbc,gsm

a call between the two systems as shown above fails.

But if this is arranged as:

Type=user
disallow=all
allow=ilbc
allow=gsm

Type=peer
disallow=all
allow=ilbc
allow=gsm

the call succeeds using ilbc.

Any thoughts on why the first codec ordering method fails?

Rich