<div dir="ltr"><div><div><div>Rob is correct in that you can use NMs that support DSPs on the NM to have separate clocking domains. On the new ISR4k line, we have the option of placing DSPs on the T1 module (NIM) which will allow us to support multiple clocking domains. Some people are placing DSPs on the NIM for the T1 interface and then DSPs on the on-board slots for DSP farm applications.<br><br></div>Typically with different providers you would encounter different clocking domains and therefore you will see slips. If you're using on-board DSPs it's not recommended that you bring multiple providers into the same box. <br><br></div>Sometimes you'll get lucky and a CLEC is clocking off the ILEC and therefore they are in sync and you can clock off one and not see slips with the other. Another lucky situation is when the ILEC is really providing the service/circuit (thus clocking) and you're just being billed by a CLEC. So it pays to know exactly how things are provisioned. Usually your ILEC guy can give you the low-down if you ask nicely when he shows up to install the circuit.<br><br></div>Andrew<br><div><div><br></div></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Wed, Apr 22, 2015 at 3:50 PM, Rob Dawson <span dir="ltr"><<a href="mailto:rdawson@force3.com" target="_blank">rdawson@force3.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Whichever interface you select in the ‘network-clock-select’ command provides signal to the PLL, which controls the on-board clocking domain. The other interface
will get clock from the line on the RX buffer, but since the TX buffer is using the on-board domain for clock you will get slips on that interface. You can only have one clock source for the on-board PLL.<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">It may not cause issues, but I have certainly seen instances of dropped calls and other anomalies where the only abnormal diagnostic was clock slips, and correcting
the slips resolved the issues.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">I think that you can use network modules to split the clock domains since they have their own onboard PLLs.<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Rob<u></u><u></u></span></p>
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<p class="MsoNormal"><b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif"">From:</span></b><span style="font-size:10.0pt;font-family:"Tahoma","sans-serif""> cisco-voip [mailto:<a href="mailto:cisco-voip-bounces@puck.nether.net" target="_blank">cisco-voip-bounces@puck.nether.net</a>]
<b>On Behalf Of </b>Ryan Huff<br>
<b>Sent:</b> Wednesday, April 22, 2015 3:38 PM<br>
<b>To:</b> Matthew Loraditch; <a href="mailto:cisco-voip@puck.nether.net" target="_blank">cisco-voip@puck.nether.net</a><br>
<b>Subject:</b> Re: [cisco-voip] T1 Clock source question<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Calibri","sans-serif"">That's correct, and that is where I am at. I have different carriers and I am wondering if I should/need to use multiple clock sources? I'm in way-back mode myself
here.<br>
<br>
I have a T1 PRI and a T1 CAS (separate providers). Can't I just clock source one and it provides that clock on the backplane to everything?<br>
<br>
Thanks,<br>
<br>
-r<u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-family:"Calibri","sans-serif"">From:
<a href="mailto:MLoraditch@heliontechnologies.com" target="_blank">MLoraditch@heliontechnologies.com</a><br>
To: <a href="mailto:ryanhuff@outlook.com" target="_blank">ryanhuff@outlook.com</a>; <a href="mailto:cisco-voip@puck.nether.net" target="_blank">
cisco-voip@puck.nether.net</a><br>
Subject: RE: [cisco-voip] T1 Clock source question<br>
Date: Wed, 22 Apr 2015 19:33:26 +0000<u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d">This is one of my foggier areas, but wouldn’t you use multiple when you have T1s from multiple carriers? I could be wrong.. very wrong.. I love Ethernet circuits!
:P </span><span style="font-family:"Calibri","sans-serif""><u></u><u></u></span></p>
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<p class="MsoNormal" style="margin-bottom:12.0pt"><span style="font-size:10.0pt;font-family:"Calibri","sans-serif";color:#1f497d">Matthew G. Loraditch – CCNP-Voice, CCNA-R&S, CCDA<br>
Network Engineer<br>
Direct Voice: <a href="tel:443.541.1518" value="+14435411518" target="_blank">443.541.1518</a></span><span style="font-family:"Calibri","sans-serif""><u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1f497d"> </span><span style="font-family:"Calibri","sans-serif""><u></u><u></u></span></p>
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<p class="MsoNormal"><b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif"">From:</span></b><span style="font-size:11.0pt;font-family:"Calibri","sans-serif""> cisco-voip [<a href="mailto:cisco-voip-bounces@puck.nether.net" target="_blank">mailto:cisco-voip-bounces@puck.nether.net</a>]
<b>On Behalf Of </b>Ryan Huff<br>
<b>Sent:</b> Wednesday, April 22, 2015 3:27 PM<br>
<b>To:</b> <a href="mailto:cisco-voip@puck.nether.net" target="_blank">cisco-voip@puck.nether.net</a><br>
<b>Subject:</b> [cisco-voip] T1 Clock source question</span><span style="font-family:"Calibri","sans-serif""><u></u><u></u></span></p>
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<p class="MsoNormal"><span style="font-family:"Calibri","sans-serif"">I have always subscribed to the idea that you should use one clocking source in situations where you have multiple T1's. In fact, I've read (not experienced) that when you use multiple clocking
domains, that in-fact can sometimes cause slips.<br>
<br>
Can anyone explain the advantages of using multiple clocking sources?<br>
<br>
Thanks,<br>
<br>
Ryan<u></u><u></u></span></p>
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