disabling multicast breaks park lights on layer2 phone system

[greg24]

I hope the subject isn't too cryptic.  I have been analyzing my network traffic and turning off unnecessary traffic (printers with IPX/SPX and appletalk enabled, turning off spanning tree, etc).  I have researched everything as best I could before disabling the traffic.  This morning I turned off pim on my 3Com 5500 switch.  According to the 5500 manual PIM is used for routing.  My network uses static routes so I turned it off.  A couple hours later I received a phone call that the park lights on the phones stopped working.  I did a quick test and sure enough park lights were not coming on.  The park function worked, but the corresponding lights did not turn on.  I enabled pim on the 5500 and the park lights started working again.  This where things get interesting, all but 2 of my 100 phones are on the same ethernet segment as the NBX v5000.  The 98 phones do not have an IP address.  I don't care if the lights work on the 2 phones that are not on the same segment as the NBX.  The second interesting thing is the boot time of the phones.  When pim is enabled a phone boots in 33 seconds.  When pim is disabled the same phone takes 3 minutes 10 seconds to boot.  It stalls at the mac address S6.0.55 12Aug0 screen.  The nbx is running 6.5.22p3.

So why do the parking lights need multicast enabled when they are on the same segment as the NBX.

Why does booting a phone take so much longer when multicast is disabled?

[bosoxfan]

yes, the NBX uses layer 2 multicast  and/or layer 3 multicast for such things as park lights, mapping buttons to analog line ports, paging, conferencing.... so not only will your park lights not work, but no conferening would work either.

..booting phone sends out a mutlicast packet looking for the nbx.. not finding any, it then will see what

is in the eeprom for the last nbx it found....

[greg24]

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@bosoxfan wrote:

yes, the NBX uses layer 2 multicast  and/or layer 3 multicast for such things as park lights, mapping buttons to analog line ports, paging, conferencing.... so not only will your park lights not work, but no conferening would work either.

..booting phone sends out a mutlicast packet looking for the nbx.. not finding any, it then will see what

is in the eeprom for the last nbx it found....

---

Thank you for the response.  I disabled multicast at layer 3.  It should have only affected the two phones that are not on the same ethernet segment as the NBX.  Disabling multicast at layer 3 affected all phones even those on the same ethernet segment.

Again layer 2 mutlicasts should not have been affected.  The NBX is in IP-on-the-fly mode if that helps.  It has to stay that way until I can figure out how to properly vlan a 3Com 4400 switch and get those last 2 phones on the same segment as the NBX.  I sense a late night experimenting with multicast coming up....

[merlin215]

send me your email address and I will send you a doc thatw as written back in 2004 I believe . It will explain all about nbx Networking including multicast

[greg24]

I sent you my email in a private message. Thanks.