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New Member

Audio issues (excessive jitter), EX90 to CTS

EX90s running TC5.1
CTS running 1.8.1

Calls from the the EX90 to a CTS room are  show an amazing amount of jitter. I've tried TC5.01 and TC5.1 so I not convinced it is a software issue.

The attached screen shot is a EX90 in London and a CTS in Chicago. 5600ms of jitter seen from the EX90 transmit side. The CTS rooms looks fine.

I have CTS rooms in both locations and they have no issues.

Has anyone seen any issues with interop between the EX90/C-Series and CTS running the latest code? It's odd, because the ex90 is not reporting jitter on the video, just audio?

Call rate: 1472 kbps

Protocol: sip

Transmit Call Rate:

    1472 kbps

Receive Call Rate:

    1472 kbps



Audio           Transmit               Receive

Protocol               G722                    G722

Channel rate          62 kbps               42 kbps

Resolution          -          -

Jitter                    5260 ms               21 ms

Loss                   0 %                       21 %

Video          Transmit          Receive

Protocol          H264          H264

Channel rate          1284 kbps          397 kbps

Resolution          1280x720@30          1280x720@20

Jitter          0 ms          0 ms

Loss          0 %          21 %

  • TelePresence

Audio issues (excessive jitter), EX90 to CTS

Jitter is not your only problem here.  You're seeing 21% packet loss on recieve; this is HUGE.  You're lucky the call even stays up.

With the packet loss alone, I'd say you need to look at your network for problems: interface speed or duplex mismatches, bad cables, interface errors, etc. You could have QoS issues too, or interface saturation.  Try at a much lower call speed (192kbps) and see if the issue is as bad.

With Jitter piled on top of that, it could be a number of things.  You could have an ISR router with IPS enabled checking every packet and getting overwhelmed--the CPU is maxxing out.

Just as a test, I would connect the Ex90 to the same port the CTS normally uses, make sure the EX90 is configured for QoS the same way (if applicable), and test.  If the problem goes away, you know you're looking at a network problem.

New Member

Audio issues (excessive jitter), EX90 to CTS


Thanks for the feedback, but the thing that makes me suspect code rather than network, is we basically have two sites. They each have a CTS3210 and an EX90. EX90 to EX90 is fine. CTS to CTS is fine. EX to CTS looks terrible.

Are many people doing the CTS to EX/C-series?


Cisco Employee

Audio issues (excessive jitter), EX90 to CTS


It can be a complete different path

What is your setup ? both CTS and EX registered directly into CUCM or you use a SIP trunk from CUCM to a  VCS and you have CTS endpoints registered to CUCM and EX registered to VCS ?

Is this a pure sip-sip call or you intework the call ?

Can you check how the media it's routed in the CTS / EX case ? I would still bet on the network here. do you have by any chance a loop in the call path ( ie, taking the media twice throuhg the same firewall or someting simmilar ? )

CTS 1.8 and EX TC5 it's supported scenario so it should work fine

Endpoint interoperability, page 23 of the TC5 release notes :

New Member

Audio issues (excessive jitter), EX90 to CTS

CTS connected to CUCM, SIP trunk to VCS where the EX90s are registered.
Call is SIP to SIP, no Interworking.

No firewalls.

Region is CUCM is setup for Wideband/AAC, can the TC5 software deal with that? Or should I set that the G.711?


Cisco Employee

Audio issues (excessive jitter), EX90 to CTS


This is certainly not interop issue. I have handled one such case where customer was using CTS endpoints behind CUCM and EX/C series endpoints registered behind VCS. Point to Point call worked fine.

I agree with Anthony, this is network problem. The value of de-jitter buffer is usually 20 ms.

Such high value of jitter and loss indicates either incorrect QoS marking or network congestion.

Plug EX90 to the same subnet of CTS endpoint and make a test call.



Audio issues (excessive jitter), EX90 to CTS

I believe that you should check the link between CUCM and VCS. That seems to be the problem here. Also, Sagar is right, if you plug the EX90 to the same subnet, the signalling would go through the CUCM & VCS but the media would flow between the subnet, so that should show some good results.

Also, can you provide the xconfig SIP from the EX90 to see what the configuration looks like?

Thanks Mubashshir Akhtar
New Member

Re: Audio issues (excessive jitter), EX90 to CTS

Thanks for the additional info.

So, here is what is setup between the VCS and CUCM. Each server is connected physically to a different Nexus2248 fabric extender. Each of those fabric extenders is connected to the same same Nexus 5k. Logically, there is a simple sip trunk configured between the CUCM and VCS following this doc

The VCS and CUCM are in the data center across town from this location and there is a 1 gig metroE connection from the Nexus5k to a C4900M

I've verified every interface, they are all clean. We know the QoS is ending up in our Real-Time queue at the WAN router.

Can you be a bit more specific on what you might check on the connection between the VCS and the CUCM?

many thanks

xconfig sip

*c xConfiguration SIP Profile 1 URI: ""

*c xConfiguration SIP Profile 1 DisplayName: "M W"

*c xConfiguration SIP Profile 1 DefaultTransport: Auto

*c xConfiguration SIP Profile 1 TlsVerify: Off

*c xConfiguration SIP Profile 1 Type: Standard

*c xConfiguration SIP Profile 1 Outbound: Off

*c xConfiguration SIP Profile 1 Proxy 1 Discovery: Manual

*c xConfiguration SIP Profile 1 Proxy 1 Address: ""

*c xConfiguration SIP Profile 1 Proxy 2 Discovery: Manual

*c xConfiguration SIP Profile 1 Proxy 2 Address: ""

*c xConfiguration SIP Profile 1 Proxy 3 Discovery: Manual

*c xConfiguration SIP Profile 1 Proxy 3 Address: ""

*c xConfiguration SIP Profile 1 Proxy 4 Discovery: Manual

*c xConfiguration SIP Profile 1 Proxy 4 Address: ""

*c xConfiguration SIP Profile 1 Authentication 1 LoginName: ""

*c xConfiguration SIP Profile 1 Authentication 1 Password: ""

** end


Audio issues (excessive jitter), EX90 to CTS


I am not very familiar with the equipment you are using for the networking. I know how VCS, EX90 & the CUCM works. When I say check the connection between the VCS and CUCM, I mean to say that check for the network connectivity from the CUCM to the VCS and vice versa and verify if you are getting any packet loss between the two.


Mubashshir Akhtar

Thanks Mubashshir Akhtar

Audio issues (excessive jitter), EX90 to CTS

Hi Robert,

This is Vivek, I would just want to confirm one thing:

VCS and CUCM are at same location i.e. in data center

This two site at different location connected through 1Gig Nexus5k

Please confirm me if i am right or not ?

I would also like to confirm that EX90 are at different location registered to VCS in datacenter, so when you are calling b/w EX90, there is no issue, right ?

So network for above scenario might be:

EX90(Site A) - VCS (in Data center)-Ex90(Site B)  ===> No Issue

When you are making call b/w Ex90 and CTS, whether on same site or on different site, getting jitter in video sending and packet loss in Video receiving as i saw it was around 20-26%.

So network might be :

Ex90(Site A)-------- VCS(Data Center) -SIP TRUNK-CUCM (Data Center) ---------- CTS (Site A)

Ex90 (Site A) ------------- VCS(Data Center) -SIP TRUNK - CUCM (Data Center) ------------CTS (Site B)

In both cases you face issue, right ?



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