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  • Voice Quality Issues

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    i am running into an issue with there being alot of static and whitenoise on calls to the PSTN (PRI) from Paetec. they ran a capture on their cisco router and said that they did not hear anything when the call was played back. i had the customer test internal and site to site to see if they heard the issue and they told me it was fine on both of those. i am not sure if it is a network config issue in the data gear or an issue with shoretel equipment. i have posted my config of the switchgear from both sites and they are extreme X-450E-48P series. site 1 has a stack of 5 and site 2 is one stand alone. any extreme gurus let me know if i need to change or add anything on the config to ensure good QOS. the DHCP server is attached to a juniper router 240 series port setup for access mode. also any juniper experts how are these router for QOS on shoretel. i am open to any suggestions to get this resolved. it is starting to have the snowball affect with users starting to complain about quality.
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  • #2
    Test the crossover cable

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    • #3
      You might also check the data/telecom wiring at both sites and make sure it's not running parallel with any power cabling. We had a couple of static issues with our old telecom equipment that was caused by running the wiring in too close proximity of the power cabling. We've since redone our data center/server room to run power under the floor and network/data/telecom overhead.

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      • #4
        Record the TX and RX on your PRI trunks from the Shoretel switch when you experience the issue. You'll be able to isolate whether it is coming from your side or their side.

        The maint. guide has information on how to accomplish this from the actual SG switch.

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        • #5
          Static doesn't really correlate to network (QOS) issues. Wiring is a great place to check as well, as mentioned above.

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          • #6
            Not sure this works for you, but I have used Solarwinds network performance monitor in their engineering toolset to find problems with T1's where Paetec or Transbeam swore it was all perfect. I sometimes get a ton of "discards" not errors. It is fun sending in a chart showing errors to end an argument. In one case, it was a problem with a card at the central office (external telco switchgear), so not the isp's fault maybe, but I needed it fixed.

            $1400 nowadays (I have old version), but seems good. Probably others, this is just the one I have used.

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            • #7
              I believe most Solarwinds products also have trials that might be enough to get you through some initial troubleshooting. It is by no means inexpensive, but it is well worth the cost if you'll be needing it on a regular basis.

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              • #8
                to clarify on the situation a bit further, on the Paetec side of things they have a Dynamic IP circuit that they are routing all traffic thru. i have a sg-t1k connected to a WIC on a cisco router acting as a PRI. all site to site and internal calls are fine. the only calls i have issues with are PSTN call and i think it has something to do with all of the conversions taking place (4). the handset converts from analog to digital and the sg-t1 converts from ip to tdm and then paetec converts it back to ip and they have another conversion that takes places in their gateways. anyone else have any suggestions other than scrapping the ip circuit and putting in traditional tdm circuits to the PSTN.

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                • #9
                  Sounds like this could be an amplication issue, try adjusting you gain down in .5 db increments until it clears up.

                  400Degreez...Got a million wayz to get it!

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                  • #10
                    Are you referring to the db levels on the trunks

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                    • #11
                      Originally posted by aj1104 View Post
                      anyone else have any suggestions other than scrapping the ip circuit and putting in traditional tdm circuits to the PSTN.
                      I would be looking to get the trunk recordings as Chris suggested. That way you'll know if the static is coming from the t1k or being recieved by it. If it's coming from the t1k then your issue is not the related to all the conversions because they haven't happened yet... if it's being recieved by the t1k from outside then I'd look to capture packets on the WAN link and play the audio from that in wireshark (try playing the incoming packets only). If you hear static from on the WAN link coming in then the problem is not yours, if you don't hear it on the WAN but it's being recieved by the t1k then I'd get back to wiring - infact, I'd change all the cables anyway just to be sure.

                      All the conversions you mention are digital so shouldn't really be a source of static. Perhaps try PCMU as the only codec in the codec's list.

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