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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>If I remember correctly we’ve had leases set to 30 minutes
before without any issues. I wouldn’t go below that because the phone is going
to be renewing at a 15 minute interval. I’d check on what DHCP server you’re
using, some will check if an address is in use before issuing one (at least I’ve
experienced that on windows DHCP), and on that same note, make sure there is
enough overlap in the scopes so you don’t run out of leases due to addresses being
blocked for conflicts.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif";
color:windowtext'>From:</span></b><span style='font-size:10.0pt;font-family:
"Tahoma","sans-serif";color:windowtext'> cisco-voip-bounces@puck.nether.net
[mailto:cisco-voip-bounces@puck.nether.net] <b>On Behalf Of </b>Wes Sisk<br>
<b>Sent:</b> Thursday, September 17, 2009 4:03 PM<br>
<b>To:</b> Lelio Fulgenzi<br>
<b>Cc:</b> cisco-voip voyp list<br>
<b>Subject:</b> Re: [cisco-voip] DHCP Migration Strategy - RFC<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>depending on your nw topology this could still be a problem:<br>
CSCso60222 After DHCP Monitor service is stopped, IP is given
to DHCP clients <br>
<br>
make sure DHCP DISCOVER (and renew as a subset of DISC) will not reach the CM
server.<br>
<br>
Phones tend to go haywire when lease duration goes below something like 5
minutes so I would stay very clear of that on the order of 1 hour. I
don't have the bug for that handy.<br>
<br>
/Wes<br>
<br>
On Thursday, September 17, 2009 4:51:28 PM, Lelio Fulgenzi <a
href="mailto:lelio@uoguelph.ca"><lelio@uoguelph.ca></a> wrote:<br>
<br>
<o:p></o:p></p>
<div>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>So,
I'm planning on moving the DHCP service off a CallManager subscriber to our
central DHCP service. Past experience tells me that this shouldn't be too much
of an issue, but there are some things to look out for. For example, IP address
conflicts on phones causes both phones to reset.<br>
<br>
Here's what I'm planning on doing (testing out on one scope to begin with):<o:p></o:p></span></p>
<ol start=1 type=1>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l1 level1 lfo1'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Lower
lease time on CallManager subscriber DHCP server from 8 days to 1 hour.
Wait until all phones have a 1 hour lease.<o:p></o:p></span></li>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l1 level1 lfo1'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Change
IP helper address on interface to new DHCP server.<o:p></o:p></span></li>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l1 level1 lfo1'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Deactivate
scope on CallManager subscriber DHCP server.<o:p></o:p></span></li>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l1 level1 lfo1'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Wait
one hour until all phones have new lease on new DHCP server and all IP
address conflicts are resolved.<o:p></o:p></span></li>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l1 level1 lfo1'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Remotely
reset phones that are not co-operating.<o:p></o:p></span></li>
</ol>
<p class=MsoNormal><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Two
questions:<o:p></o:p></span></p>
<ul type=disc>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l0 level1 lfo2'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Is
having a 1 hour lease time on the subscriber an issue? It's a 7835 from
about 4 years ago and it does nothing else other than DHCP/TFTP.<o:p></o:p></span></li>
<li class=MsoNormal style='mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;
mso-list:l0 level1 lfo2'><span style='font-size:10.0pt;font-family:"Verdana","sans-serif"'>Can
I go a step further and lower the lease time to 30min or even 15 min
without significant concern?<o:p></o:p></span></li>
</ul>
<p class=MsoNormal style='margin-bottom:12.0pt'><span style='font-size:10.0pt;
font-family:"Verdana","sans-serif"'>We have about 7500 phones.<br>
---<br>
Lelio Fulgenzi, B.A.<br>
Senior Analyst (CCS) * University of Guelph * Guelph, Ontario N1G 2W1<br>
(519) 824-4120 x56354 (519) 767-1060 FAX (JNHN)<br>
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^<br>
"Bad grammar makes me [sic]" - Tshirt<o:p></o:p></span></p>
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<pre><o:p> </o:p></pre><pre style='text-align:center'>
<hr size=4 width="90%" align=center>
</pre><pre><o:p> </o:p></pre><pre>_______________________________________________<o:p></o:p></pre><pre>cisco-voip mailing list<o:p></o:p></pre><pre><a
href="mailto:cisco-voip@puck.nether.net">cisco-voip@puck.nether.net</a><o:p></o:p></pre><pre><a
href="https://puck.nether.net/mailman/listinfo/cisco-voip">https://puck.nether.net/mailman/listinfo/cisco-voip</a><o:p></o:p></pre><pre> <o:p></o:p></pre>
<p class=MsoNormal><o:p> </o:p></p>
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