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</o:shapelayout></xml><![endif]--></head><body lang=EN-AU link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='color:black'>Hi Ryan,<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>Thanks for that.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>We do not have any 9971 phones in this setup.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>Most are 7941 and 7942 models. There are a few 7961 phones and a few 9951 phones.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>The problem I am trying to solve is that some of the 7942 phones just appear to drop off of the network from time to time.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>When this occurs, I can not ping the phone even from its own default gateway, yet it is still registered to CUCM and can make/receive calls.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>I however, get one way audio from that phone when the problem occurs.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>We are thinking that their arp cache (something small like 16) is getting full and wanted to be able to flush that out every five minutes with the dhcp option.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'>Is there a way to set the ARP cache timeout from within Call Manager itself by any chance?<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>Thanks for any help.<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>Regards<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:black'>Amanda<o:p></o:p></span></p><p class=MsoNormal><span style='color:black'><o:p> </o:p></span></p><div><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Ryan Ratliff [mailto:rratliff@cisco.com] <br><b>Sent:</b> Monday, 8 October 2012 10:56 PM<br><b>To:</b> alalli@iinet.net.au<br><b>Cc:</b> cisco-voip@puck.nether.net<br><b>Subject:</b> Re: [cisco-voip] setting the ARP cache timeout for phones using DHCP option<o:p></o:p></span></p></div></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>CSCtf62463 seems to indicate the 9971 phones don't support DHCP option 35. This will vary by model so YMMV.<o:p></o:p></p><div><p class=MsoNormal><o:p> </o:p></p><div><p class=MsoNormal><span class=apple-style-span><span style='font-family:"Helvetica","sans-serif"'>-Ryan</span></span> <o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><div><p class=MsoNormal>On Oct 8, 2012, at 4:10 AM, <a href="mailto:alalli@iinet.net.au">alalli@iinet.net.au</a> wrote:<o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p><div><div><div><div><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Currently Being Moderated<o:p></o:p></span></p></div><h2><span style='font-family:"Helvetica","sans-serif"'><a href="x-msg://184/message/3751318#3751318">Configuring the ARP cache timeout for Cisco phones</a><o:p></o:p></span></h2></div></div><div><div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Hi All,<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>I am hoping to configure the ARP cache timeout for Cisco phones using the dhcp option.<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>I was wondering if anyone here has done it or can verify that this would be correct.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Say for example I have a DHCP pool named VOICE.<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>In this network, the CUCM is located at IP address 10.2.200.110 <o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>I did some google searching and found a Wiki site with the various dhcp options defined in it.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'><a href="http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol">http://en.wikipedia.org/wiki/Dynamic_Host_Configuration_Protocol</a><o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>According to the site, dhcp option 35 is used as the ARP Cache Timeout value and it is 4 bytes long.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Lets say that I would like to set my arp cache timeout to be 300 seconds.<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>I convert 300 to hex and get 12C.<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Since my field will need to be four bytes long this becomes 0000.012C.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>I think that the following dhcp pool will provide 300 seconds for the phone ARP cache timeout.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>ip dhcp pool VOICE<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>network 10.240.1.0 255.255.255.0<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>default-router 10.240.1.1<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>option 150 ip 10.2.200.110<o:p></o:p></span></p><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>option 35 hex 0000.0c12 <o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Can anyone help me out with a verification or point me in the direction of the appropiate documentation?<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Many thanks for any assistance.<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Regards<o:p></o:p></span></p><div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'> <o:p></o:p></span></p></div><p><span style='font-size:9.0pt;font-family:"Helvetica","sans-serif"'>Amanda Lalli-Cafini<o:p></o:p></span></p></div></div></div></div><p class=MsoNormal>_______________________________________________<br>cisco-voip mailing list<br><a href="mailto:cisco-voip@puck.nether.net">cisco-voip@puck.nether.net</a><br><a href="https://puck.nether.net/mailman/listinfo/cisco-voip">https://puck.nether.net/mailman/listinfo/cisco-voip</a><o:p></o:p></p></div><p class=MsoNormal><o:p> </o:p></p></div></div></body></html>