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New Member

Help with SIP one way voice - will Cisco Router solve issue?

hi All,


We have subscribed to a SIP provider(Inmarsat). We are supplied with a sip hardphone for voice calls.

We have 5 sip client hardphones connected to an "off-the-shelf" router.

It successfully registers to the SIP provider, but we are getting on way audio call.


We would like to propose a cisco router or ASA firewall, will it solve the issue of one-way audio?

If so what sort of feature are we looking at in the router/firewall

appreciate any advise

Hall of Fame Super Gold

One way call is a mostly

One way call is a mostly caused by an invalid NAT entry.  

New Member

is there any cisco product

is there any cisco product/features that can solve that?

Hall of Fame Super Gold

No.  This means that your NAT

No.  This means that your NAT is configured incorrectly.  Throwing money is not a solution.  You'll need to work with your VSP to figure out where your NAT problem lies and fix it.

New Member

Thanks for the info.We are

Thanks for the info.

We are going to replace it with a cisco router anyways. Do we just do the normal dynamic PAT on the router? We cant do a static 1-1 nat as we have several of the SIP phones

Hall of Fame Super Gold

What you are doing is

What you are doing is inefficient.  


It is better to configure a call server box, like Cisco CUCM.  


All your phones talk to your call server and your call server talks to your VSP.    What you are planning is all your phones talk to your VSP.  That's inefficient.

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