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<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>I'm the furthest thing from a Multicast expert, but to my
knowledge the static join is joining only the router interface to the multicast
stream and it forwards the packets continuously. But, when the packets
get to the L2 switch, it doesn't have an active IGMP join in it's table so it
doesn't forward the traffic out any ports. Then when the phone joins the
group it is instantly available at the access layer due to the static join.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";
color:#1F497D'>So, if anything this tells you that your delay is between the L3
devices and not at the access layer. <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>
<p class=MsoNormal><b><i><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'>Tony Underwood CCIE #7112<o:p></o:p></span></i></b></p>
<p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'>Sr. Network Engineer<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'>Cambium Data Inc.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'>5050 So. 111th St.<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'>Omaha, NE 68137<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'>(402) 556-1388<o:p></o:p></span></p>
<p class=MsoNormal><span style='font-size:10.5pt;font-family:"Arial","sans-serif";
color:#1F497D'><a href="http://www.cambiumdata.com/"><span style='color:blue'>http://www.cambiumdata.com</span></a><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>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<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-bounces@puck.nether.net [mailto:cisco-voip-bounces@puck.nether.net] <b>On
Behalf Of </b>Daniel<br>
<b>Sent:</b> Wednesday, June 24, 2009 5:44 PM<br>
<b>To:</b> cisco-voip@puck.nether.net<br>
<b>Subject:</b> Re: [cisco-voip] Multicast MoH Delay<o:p></o:p></span></p>
</div>
<p class=MsoNormal><o:p> </o:p></p>
<div>
<p class=MsoNormal>Thanks all for your replies<o:p></o:p></p>
</div>
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<p class=MsoNormal> <o:p></o:p></p>
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<div>
<p class=MsoNormal>I would rather use sparse mode to take use of the join
messages etc.. so that the phones join and leave the group. Dense mode I think
floods the network and then prunes interfaces that are not in use, this occurs
every 3 minuts or so. It just seems that sparse mode is more precise, I don't
have much experience in this so not sure. Any thoughts / technical
reasons on why to go Sparse, Dense or both?<o:p></o:p></p>
</div>
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<p class=MsoNormal> <o:p></o:p></p>
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<div>
<p class=MsoNormal>The RP is on a 6500 with sup720s and MSFC3's, the other
distribution switch is an older 6500 with SUP2s and MSFC2, so c3voip
similair to the issue you had with TAC but the RP is on a different device.<o:p></o:p></p>
</div>
<div>
<p class=MsoNormal> <o:p></o:p></p>
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<div>
<p class=MsoNormal>I have added the "ip igmp join-group
group-address" command in, this fixes the issue. My question is with this
command, the router will accept and forward these packets preventing fast
switching, if i use the static-group command the router doesnt accept the
packets itself but forwards them thus allowing fast switching, anyone know of
benefits either way? I did originally have a look at this command but I assumed
its use was to always have the multicast traffic flowing which I didnt think
ideal. But it turns out after actually trying this from Tony's point below
it works quite well. Between the dsitribution switches the mroute is always
setup but not from the distribution switch to the floors, when the phone joins
the group the phones vlan interface is added to the mroute and MoH is heard
straight away. There is no multicast MoH flooding the floor vlans which is what
I was concerned about.<o:p></o:p></p>
</div>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal> <o:p></o:p></p>
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<p class=MsoNormal><br>
<br>
<o:p></o:p></p>
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<p class=MsoNormal>On Thu, Jun 25, 2009 at 5:49 AM, Tony Underwood <<a
href="mailto:tony@cambiumdata.com">tony@cambiumdata.com</a>> wrote:<o:p></o:p></p>
<div>
<div>
<p><span style='font-size:11.0pt;color:#1F497D'>If it's a delay in the route
set up then you could try a static igmp join on the far end router.</span><o:p></o:p></p>
<p><b><span style='font-size:9.5pt;color:black'>ip igmp join-group </span></b><em><span
style='font-size:9.5pt;color:black'>group-address</span></em><o:p></o:p></p>
<p><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p>
<p><b><i><span style='font-size:10.5pt;color:#1F497D'>Tony Underwood CCIE #7112</span></i></b><o:p></o:p></p>
<p><span style='font-size:10.5pt;color:#1F497D'>Sr. Network Engineer</span><o:p></o:p></p>
<p><span style='font-size:10.5pt;color:#1F497D'>Cambium Data Inc.</span><o:p></o:p></p>
<p><span style='font-size:10.5pt;color:#1F497D'>5050 So. 111th St.</span><o:p></o:p></p>
<p><span style='font-size:10.5pt;color:#1F497D'>Omaha, NE 68137</span><o:p></o:p></p>
<p><span style='font-size:10.5pt;color:#1F497D'>(402) 556-1388</span><o:p></o:p></p>
<p><span style='font-size:10.5pt;color:#1F497D'><a
href="http://www.cambiumdata.com/" target="_blank">http://www.cambiumdata.com</a></span><o:p></o:p></p>
<div>
<p><span style='font-size:11.0pt;color:#1F497D'> </span><o:p></o:p></p>
<div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in 0in 0in'>
<p><b><span style='font-size:10.0pt'>From:</span></b><span style='font-size:
10.0pt'> <a href="mailto:cisco-voip-bounces@puck.nether.net" target="_blank">cisco-voip-bounces@puck.nether.net</a>
[mailto:<a href="mailto:cisco-voip-bounces@puck.nether.net" target="_blank">cisco-voip-bounces@puck.nether.net</a>]
<b>On Behalf Of </b>Daniel<br>
<b>Sent:</b> Wednesday, June 24, 2009 1:46 AM<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] Multicast MoH Delay</span><o:p></o:p></p>
</div>
<p> <o:p></o:p></p>
</div>
<div>
<p>Hi All,<o:p></o:p></p>
</div>
<div>
<div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>I've setup multicast routing for music on hold between our data centre
network and building floor subnets. The setup is that the data centre is on a
different subnet and gear to the floor subnets so multicast routing needs to be
used to get MoH packets to the phones.<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>This consists of the following traffic flow,<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>MoH Server > Access Switch > Distribution Switch/router(RP) >
Distribution Switch/router > Floor Switches > Phones<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>There are three routing hops (1) from vlan interface to routed
interfaces of distribution switch (2) between Distribution and (3) from routed
interface of distributionswitch to phone vlan interface. Only the
distribution switches are layer 3.<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>The first distribution switch is the RP for the group and only that
group.The second distribution switch is accepting auto RP only. We are using
sparse mode.<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>Multicast traffic is working, the RP mappings are there, the mroute is
there, the problem is that when a call is placed on hold there is a 5 second
delay before the music is heard. I assume this to be somewhat because of the
join message and the delay of the route or path being setup.<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>Anyone know of a way to reduce the delay before music is heard? If not I
guess its back to the lab.<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>regards,<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
<div>
<p>Dan<o:p></o:p></p>
</div>
<div>
<p> <o:p></o:p></p>
</div>
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<p class=MsoNormal><o:p> </o:p></p>
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