VCS Control - Should Assent and H460 be active?

[j.house]

I have VCS control and Expressway in production Assent and h460 are both active on the expressway, but inactive on control.  Is this correct?

[mubakhta]

Hi,

My name is Mubashshir and I am from the Telepresence Support Team. The way Firewall Traversal works is that the VCS Control maintains an active connection with the VCS Expressway. Only then the calls coming from outside the network are communicated to the VCS Control and VCS Control initiates the call from the internal network which is behind the firewall.

Ideally, it needs to remain active on both Control & Expressway. Are your traversal calls working fine ? Try to make a call from outside the network to the inside network which is behind the firewall and see if it works.

Please rate the answer using the stars below this post.

Regards,

Mubashshir Akhtar

[j.house]

Yes, my traversal calls are working.  I am receiving outside calls in and able to place inside calls out.  The specific issue that caused me to question assent and h460 is that I have a number of h323 LifeSize endpoints registered with VCS Control but when they dial out they are having issues with audio codec negotiation.  When calling an external h323 endpoint we get one-way audio and on the receive side garbled audio.  If the same enxternal endpoint dials in the codec is negotiated correctly and the call is successful.  If I register the endpoints back with their old h323 gatekeeper,  calls are placed fine and the AAC codec is successfully negotiated.  I thought that maybe if I registered the LS endpoints with h460 enabled the issue may be corrected.  but when I enable h460 on the LS endpoint I can no longer register it with VCS Control.

[mubakhta]

Hi,

When you make H.460 and Assent active on the VCS Control, does that resolve the issue ?? Have you tried to do that...?? If not, can you try and share the results ? Also can you please let us know both the endpoints that are involved in the call and the setup of your devices including the VCS as well as the endpoints ??

Regards,

Mubashshir Akhtar

[j.house]

Making assent and h460 active is proving difficult

I can't seem to find any reason for them to be "inactive" (again both are active on VCS Expressway, just not on Control).

thoughts?

[awinter2]

A VCS Control can not act as a traversal server for endpoints registering to it, which means that a VCS Control can not use Assent/H.460 for locally registered endpoints. For that you would need a VCS Expressway.

- Andreas

[j.house]

So, since I have Expressway it is normal for assent and h460 to show "inactive" on the VCS Control then....correct?

Any thought as to what would be causing my Audio codec negotiation issue on outbound calls I outlined above?

Thanks for the input.

[Martin Koch · Accepted solution]

I assume you saw the "inactive" on a xstatus or on the https:///h323 page, right, or is it mentioned

somewhere else as well?

Maybe Andreas could follow this up an improvement request, as at least it can be confusing.

On a VCS-C it shows up in red letters (at least) on the h323 config page.

Maybe not showing it at all on the vcs-c might be handy as well, ....

In general h460 is one of the parts which makes the expressway an expressway.

If you would try for example to access the

https:///locallyregisteredendpoints page it would tell you that you lack a license.

h460 is one of the parts which makes the expressway the expressway.

So this "Inactive" this is nothing you need to worry about, that's the wanted behavior. And its

ok that h.460 is not used on the vcs-c (its not a bug its a feature :-)

If your firewall allows it and your VCS-E is set up for it you could try to register the endpoint

with h.460 to the VCS-E.

In general when having strange symptoms its worth checking that there is no NAT helper / Application

layer gateway or what ever in between the involved components and that the firewall ports are properly

configured and the traversal zone and search rules are properly set up.

Also reading release notes and possibly upgrading to the latest software versions.

The traversal zone has the options has two h323 options which I would try to play around in such a case:

"H.460.19 demultiplexing mode"  and "Protocol" (has to be the same on vcs-c and -e).

Andreas: what are the use cases for these parameters?

Anyhow, its strange with the garbled sound.

J.House:  Please rate the answers using the stars below the messages!

[j.house]

martin, thanks for the explanation.

The garbled voice is coming from a Codec mismatch (on outbound calls the codec is not being negotiated properly).

I have a LS endpoint in a remote office....this remote office has it's own internet connection.  the LS endpoint is registered with VCS-c in our data center.  If the LS unit places an outbound call to an IP address will it go out the local internet connection or via VCS and our Data Center?

[Martin Koch]

I never traced if the VCS is changing anything regards the codec negotioation in h323, but

I would have expected not, so really double check if an ALG kicks in which does not like

the signalling of the VCS.

Besides that if the endpoint does not define bandwidth the VCS would set the default

value, maybe this is different from your GK, and the endpoints try to use a different codec

set based on the bandwidth used.

Do you use a VPN tunnel or is your VCS-C on a public IP?

I am not aware of your deployment, but in general:

the VCS-C is most likely to be used in the internal network with all its devices firewalled from the outside.

All devices in the inside need a wide range of ports to be open.

It is possible to run a VCS-C on a public IP and all other systems have to be wider open as well but

thats what I would not recomend, thats why the combination of the VCS-C and -E exists.

In your case if its really a system from the internet I would register it to the VCS-E, which on

H323 is really a registration on the VCS-E, on sip you could also choose on proxy register it

to the VCS-C.

I would strongly recomend that you contact your local cisco telepresence partner to do a review of your setup.

They also might be able to help you further with additional questions or the audio issue you have.

Besides that I can recomend the documentation you can find on the cisco site:

http://www.cisco.com/en/US/products/ps11337/tsd_products_support_series_home.html

These could be a good start:

http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/config_guide/Cisco_VCS_Basic_Configuration_Cisco_VCS_Control_with_Cisco_VCS_Expressway_Deployment_Guide_X7-1.pdf

http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/config_guide/Cisco_VCS_IP_Port_Usage_for_Firewall_Traversal_Deployment_Guide_X4_to_X7.pdf

http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/config_guide/Cisco_VCS_Authenticating_Devices_Deployment_Guide_X7-1.pdf

http://www.cisco.com/en/US/docs/telepresence/infrastructure/vcs/admin_guide/Cisco_VCS_Administrator_Guide_X7-1.pdf