One Way RTP voice problems using CME

Originally posted by Kristján Ólafur Eðvarðsson

Hi all,

I have this One Way Voice issue with CME through PSTN PRI. This happened af=
ter I started connecting Internet straight to the CME instead of =

letting another router do it.

Past:
I have been using cisco 2811 and CME for some time. The CME registers other=
remote IP phones
over ipsec tunnel terminated at a same network router. Those far end phones=
use the PSTN on my site with success.

Present:
However when I set up a Internet connection straight to my CME (using G.SDH=
SL VIC, skiping the older Internet Router that used to terminate the VPN) a=
nd a Ipsec tunnel
to the same destination as before (Cisco PIX) I have these facts:

1. IP phones locally and on the far end can comunicate with out problems as=
before.
2. Far end IP phones can be called via the PSTN and they can call through p=
stn but always we have one-way voice problem. Far end hears nothing but PST=
N hears them
(other call controll seems to work, like ringback, remote phone is ringing=
etc.)
3. I tried to include the CME Internet IP address to the tunnel, so it woul=
d be included when the router itself was orginating packets but that didn=
=B4t change anything.

Anyone had this issue or have faced this particular problem ?

For clarification, the schenario is like this:

PSTN----Local IP phones---CME<------------------<WAN/Internet>------------>=
PIX-----remote IP phones<registerd to the CME =

regards. Kristjan Edvardsson
CCNP - MCSE
Sensa ehf. cisco Silver Partner