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Thread: Quadro 2xi & Thomson ST2030

  1. #1

    Default Quadro 2xi & Thomson ST2030

    Hello.

    I have a site using a Quadro 2xi and 12 Thomson ST2030 phones, plus one Aastra 57i phone.
    Since day one, I have had issues with communications quality. Like, users report choppy sound and even from time to time barely understandable speech.
    This has been happening both on incoming and outgoing calls, through either WAN interfaces (ISDN or SIP trunk, two different SIP providers), both on the ST2030s and the 57i. This has not been seen on internal calls, though.

    1/ any ideas ?

    2/ I have read somewhere that there's a guide for configuring ST2030s for use with Epygi PBX, but I can't seem to locate the document.

    Thanks for your help,

    R.

  2. #2
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    Do you mean the installation have the same problems with both ISDN calls (done through onboard ISDN connection), and SIP calls to ITSP provider? Can you confirm that?
    If so, the only suspected part should be the 2xi placement in the network (probably bad switches or something this kind), as if you have the same choppy audio when talking to ISDN, this means the packets are lost between phones and Quadro.
    Did you look at the network statistics of those bad calls (especially to the ones going to ISDN)? Is there a packet loss or big jitter/delay?

    Regarding the document on configuring the ST2030: there is no special document for those phones, but some guidance can be found in the documents called "Configuring Epygi Tested IP Phones" and "Quadro Features on Epygi's Tested IP Phones list". Just search the download area using the word "tested" and you'll find those documents.

    Best regards,
    David

  3. #3

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    Hello, and thanks for your answer.
    Regarding your first question, yes we have the same issue with both ISDN and SIP calls, both inbound and outbound.
    But not with entirely internal calls.
    For you reply I guess I should look into the network. The fact that network connections are shared between the phones and the computers might be a problem. Are there some settings on the phones or on the Epygi to prioritize the voice traffic over data packets?

    Thanks for your help,

    R.

  4. #4
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    The voice traffic is prioritised on the Quadro by default. But that relates only to the traffic, which has reached the Quadro. If the packets are lost in the LAN before reaching the Quadro (for example, because of glitchy switches, which drop packets when congested), Quadro can do nothing to help there. If the quality problems never appear during internal calls (when voice stream are passing directly from phone to phone, bypassing the Quadro), it means some network equipment (for example, a switch), which is located between Quadro and phones, could be the source of the problem (it may pass too big traffic, and so may be congested).

    Best regards,
    David

  5. #5

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    Hi again. Here's the rtp log for an occurrence of a bad quality call:

    Journal RTP

    qualité: 1 (excellent)

    Local: 192.168.253.6:6076, Remote: 192.168.253.67:41000, qualité: 1 (excellent)
    RX Codec: PCMA
    Paquets reçus: 7398
    Taile des paquets reçus: 160
    Paquets RX perdus: 0
    RX Jitter: 15
    Retard maximum RX: 21 ms
    Comptage de hausse du délai de réception 0
    Comptage de baisse du délai de réception : 0

    TX Codec: PCMA
    Paquets transmis: 6123
    Taille des paquets transmis: 240

    Local: 192.168.253.6:6078, Remote: 212.27.52.129:36014, qualité: 1 (excellent)
    RX Codec: PCMA
    Paquets reçus: 6123
    Taile des paquets reçus: 240
    Paquets RX perdus: 0
    RX Jitter: 15
    Retard maximum RX: 54 ms
    Comptage de hausse du délai de réception 0
    Comptage de baisse du délai de réception : 0

    TX Codec: PCMA
    Paquets transmis: 7398
    Taille des paquets transmis: 160
    Configure Call Quality Event Notification

    Does that tell you anything about what the problem might be? FYI, I have isolated the phone network so that all phones and the Epygi are connected directly to a 10/100 switch (entry level Netgear).

    Thanks for your help,

    R.

  6. #6
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    Looking at the parameters of this call, you can see that is was really excellent quality, at least from Quadro perspective - nothing is lost in neither leg of the call, small jitter etc.
    From the statistics I see only two strange things:
    1. The "Local" IP addresses are the same in both legs of the call. That can mean only one thing: your phones are placed in the Quadro WAN side, and, but calls are proxied through the Quadro. Is that the case? If yes, why do you proxy streams through Quadro, but don't send them directly to ITSP?
    2. The media is assymmetric. Phone sends one 160byte packet every 20msec, while the ITSP (212.27.52.129) sends one 240byte packet every 30msec. This ITSP behaviour is not standard and it may confuse the phone, if the RTP stack of the phone is not so good.

    Some questions/things to test:
    1. Do your users report problems only on their end? I mean does the bad audio happen only on their phones, or the remote users (at ITSP side) also hear choppy sound?
    2. Do those problems appear on Aastra too, or it is happening with Thomson phones only?
    3. Do other, good calls also have such asymmetric media (RX packet size = 160, TX packet size = 240), or the media is symmetric there. You can see that from statistics of good calls.
    4. Do you have something placed behind the Quadro, which may cause a load on the unit, or do you use it as a router at all?
    5. Can you force the media to go directly between phones and ITSP, without RTP proxy? Probably you just need to uncheck RTP proxy on routing rule and see if you still can make calls, and have normal audio. You can do that and see if choppy sound proble still persists on ITSP calls.

  7. #7

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    The phones indeed are connected to the WAN side of the Quadro ; as per the documentation, this is the proper setup when the Quadro is not used as a router (nothing is connected to the LAN side of the Quadro). The reason why calls would be proxyed through the Quadro is not clear : I have checked the routing rules, and the proxy box is not checked. The phones are not setup to proxy either. If have tried removing the proxy address from the profile setup on a ST2030, but then I couldn't place any outgoing call at all.
    Answers:
    1- I have had reports of bad sound on both sides. These include choppy sound but also occasional echo.
    2- the Aastra has these problems as well
    3- that's not going to help us : I have seen symetric calls with bad sound, as well as asymetric calls with good quality sound...
    4- no, it's not used as a router. I can't imagine anything putting load on the Quadro, but is there any way to check? Does it have an SNMP agent (and a MIB!) that I could use to monitor it?
    5- that's an interesting track I'd like to follow. I have verified the routing rule, and the "Use RTP proxy" box is unchecked. Could there be some specific setting on the ST2030 side as well?

    For the record, here's another bad call record:

    Journal RTP

    qualité: 1 (excellent)

    Local: 192.168.253.6:6094, Remote: 192.168.253.66:41000, qualité: 1 (excellent)
    RX Codec: PCMA
    Paquets reçus: 2160
    Taile des paquets reçus: 160
    Paquets RX perdus: 0
    RX Jitter: 15
    Retard maximum RX: 12 ms
    Comptage de hausse du délai de réception 0
    Comptage de baisse du délai de réception : 0

    TX Codec: PCMA
    Paquets transmis: 2641
    Taille des paquets transmis: 160

    Local: 192.168.253.6:6096, Remote: 193.202.111.239:19362, qualité: 1 (excellent)
    RX Codec: PCMA
    Paquets reçus: 2641
    Taile des paquets reçus: 160
    Paquets RX perdus: 0
    RX Jitter: 2
    Retard maximum RX: 3 ms
    Comptage de hausse du délai de réception 0
    Comptage de baisse du délai de réception : 0

    TX Codec: PCMA
    Paquets transmis: 2160
    Taille des paquets transmis: 160

    In this call, the local user had trouble understanding what the remote user was saying. He didn't ask whether it was the same the other way around.

    For comparison's sake, here's a good call record:

    Journal RTP

    qualité: 1 (excellent)

    Local: 192.168.253.6:6084, Remote: 192.168.253.68:41000, qualité: 1 (excellent)
    RX Codec: PCMA
    Paquets reçus: 9749
    Taile des paquets reçus: 160
    Paquets RX perdus: 0
    RX Jitter: 15
    Retard maximum RX: 30 ms
    Comptage de hausse du délai de réception 0
    Comptage de baisse du délai de réception : 0

    TX Codec: PCMA
    Paquets transmis: 8903
    Taille des paquets transmis: 240

    Local: 192.168.253.6:6086, Remote: 212.27.52.129:35356, qualité: 1 (excellent)
    RX Codec: PCMA
    Paquets reçus: 8903
    Taile des paquets reçus: 240
    Paquets RX perdus: 1 (0,01%)
    RX Jitter: 15
    Retard maximum RX: 333 ms
    Comptage de hausse du délai de réception 0
    Comptage de baisse du délai de réception : 0

    TX Codec: PCMA
    Paquets transmis: 9749
    Taille des paquets transmis: 160

    Questions:
    - would it help to enable the developer's log? could you make anything of it?
    - on the phone side, I can elect to use either udp or tcp. One would think tcp would be more stable, what do you think?

  8. #8
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    I can clearly see that RTP is proxied through the Quadro (oterwise you would not have any RTP statistics on Quadro). If you are absolutely sure RTP proxy is not set on the ITSP rules, there is only one option: you configured those phones as remote extensions and set the RTP Proxy on the "Remote Settings". If this is not the case, you would probably need to enable developer logs and send them to me (after making one-two calls), as this is pretty strange.

    But I am afraid if you remove RTP proxy, you will have problerms calling out of your network. I am not sure your riuter will handle the voice streams correctly, if they go between phone and ITSP directly.

    I s it possible to look at the statistics of the bad (with choppy sound call), going to ISDN?

  9. #9

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    I haven't pinned down any bad sounding call through the ISDN line in the last couple days.

    I double-checked the proxy issue, and I can confirm the RTP proxy is not set on the ITSP rule, and the phones are not set up as remote extensions.
    FWIW, the router is a Funkwerk Bintec that has a VoIP configuration option to enable SIP proxying and prioritizing.

  10. #10
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    In this case I don't really understand why the streams are passing through Quadro.
    If you are not afraid of me hovering about your Quadro, you can give me an access to your device (my external IP is 91.198.247.202), so I can understand what is going on there.

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