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Cannot call to some external site

Abzal
Level 7
Level 7

Hello gents,

We are having some problems with calling to external sites. The phone call to that site goes through Voice Gateway in Italy. We've checked IP routing, Call Manager configurations.  Also we've checked that VG configurations it all seem ok. Nothing is blocking voice packets or UDP traffic. Last thing we've done is port span where our Cisco IP Phone (7941G) is connected with Wireshark and you did not see any voice packets coming out of that port but coming in voice packets there is no problem.

The problem is we (where call is originated) can hear other side but they cannot hear us. Call registration establishment is ok.

Call manager version is 4.3.

Please, help me out.

I will provide you with additional information if you need.

Best regards,
Abzal
32 Replies 32

Yes, you might be right. How can I check it? Or turn off.

Best regards,
Abzal

It really depends on your setup.  What is the exact call flow including voice gateway protocols?

What do you mean? Call flow goes to Call Manager after it establishes connection with remote site through WAN router and IP Phone call flow goes through that router. It is connected to our default gateway. WAN router connected with remote site by satelite connection. IP Routing protocol is EIGRP. Route to remote site learned by EIGRP.

Best regards,
Abzal

Are both phones registered to CUCM?

No, only one of them. IP phone on our LAN network is registered only. Second phone might cell phone or land line.

Best regards,
Abzal

What protocol are you using between CUCM and the gateway? H323? SIP?

We are using H.323 protocol.

Best regards,
Abzal

Do you have SRTP Allowed checked on the voice gateway configuration in CUCM?

I'm not ure about it I tried to find this option as well. But no luck.

Best regards,
Abzal

Sorry, I'm right now checking pcap file results from our tests. And I think we are using H.225. Is it possible?

Best regards,
Abzal

H.225 is just the call signaling used by H.323.  I think you may want to open a TAC case if you haven't already as I'm running out of ideas.  It seems like you are getting valid RTP streams but they are silent.  That means routing and codec negotiation should be good.  If you don't have SRTP Allowed checkbox, then you don't have cluster security turned on for CUCM so SRTP is probably not the issue.

I've checked our CallManager (version 4.3) trunk configuration and I there is no such option as SRTP allowed. But as per cisco documentation verion 5.0 has this option.

Yes, you are right there is RTP stream but they are silent. I also have no idea what could be problem.

Best regards,
Abzal

Brian thanks for your help.

But there is another site of ours, they also have same CallManager 4.3, same Cisco devices between sites, same IP phones, same connection through satelite to remote site but they don't have this kind of issue.

Best regards,
Abzal

It looks like your network subnet is not published to the remote site.

Please get this checked and publish your local network to the remote site.

Hi Piyush,

What do you mean by not published? Route to remote site is learned by EIGRP and it is ok. Or you mean in CUCM? We have trunk that points to some gateway located in remote site in CUCM configuration.

Best regards,
Abzal
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