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Dragon8 02-18-2004 10:04 PM

Mitel IP System DHCP Issues

We have started to implement a MItel solution using 3300ICP
controllers and 5201,5215 and 5220 handsets. Our network design is 2
w2k DHCP servers with multiple scopes set up and split over the 2
servers these include all the voice and data scopes. we have multiple
stub vlans setup through 2 layer 3 switches (Allied Telesyn Rapiers)
with Layer 3 interfaces on each vlan to allow routing between the
vlans all vlans come back to the same to servers for DHCP using the IP
Helper setup on the Rapiers.

The problem is with the phones hanging at boot the boot method is
below this is taken from the Mitel site

This is the normal sequence of events for a dual port IP Phone, where
VLANs are implemented:
Power up
Run ‘Boot' code
Request IP address (untagged) through DHCP
Receive IP address from default VLAN (data VLAN) and specific phone
and system options
Check VLAN information
Relinquish IP address (untagged)
Request IP address on voice VLAN (tagged)
Receive IP address from voice VLAN and specific phone and system
again Check VLAN information matches, if not repeat until it is.
Locate TFTP server
Get running code
Register with call control
The phone does a double fetch of information, so it is important to
have the same VLAN and priority information in the DHCP server
associated with the data VLAN as it is for the DHCP server associated
with the voice VLAN, i.e. copy the option data. The engineering
guideline that can be highlighted here is that this sequence works
with either multiple DHCP servers on each VLAN, or that the
router/Layer3 switch connecting the VLANs has DHCP forwarding

the phone will receive 2 DHCP offers from the data scope (
(1 from each server) it will then request one of the addresses and
then release it and move to the voice vlan where it will do a DHCP
discover and receive another 2 offers from the voice scope
( from each server)

the offers that the servers are making depend on which server issued
the first address on the data vlan if the address is taken by the
phone then the server will allocated the correct address for the voice
vlan. however the address that was not taken from the 2nd DHCP server
will be reused on the voice vlan even though it is from the wrong


phone - discover
server1- offer
server2- offer
phone - request
server1 - dhcpack
phone - release (phone then moves to voice vlan and dhcp is routed
through rapier using IP Helper

phone- discover
server2 -offer
server1- offer
phone- request
server2- DHCPNACK ( this causes the phone to hang)

I know this is long and complicated and if you have read as far as
this thanks a lot but I could really do with some help on this


James Howie CCNA

DPGumby 02-19-2004 03:09 AM

Re: Mitel IP System DHCP Issues
I'm no expert and I have never used two DHCP servers on one VLAN, so I don't
know how much help I will be.

The boot sequence looks good although I thought it was DHCP discover,
receive IP address from DHCP server along with opt 3 ( router IP address ),
option 128 (TFTP server address ), option 129 (RTC address on 3300 ), opt
130 MITEL IP PHONE, opt 132 Priority and opt 133 VLAN ( usually the same
VLAN that contains the 3300 ) . The phone looks for option 130 and if not
exactly as shown drops address and goes into DHCP discovery again and again
until it gets MITEL IP PHONE. If option 130 is correct then it compares the
IP address it receives with the IP address of the RTC to see if they are on
the same subnet. If they are not it drops all but the VLAN and priority and
issues DHCP discovery again. This time the DHCP discovery should be issued
on the voice VLAN.

This is where I get a bit confused on the routing etc ( in general not with
what you have done ). I thought the IP helper at layer 3 would send the DHCP
request back over to the data VLAN and the original DHCP servers. That DHCP
servers would see the request as coming from the 10.1.200.x subnet and would
then send back an IP address from that scope rather then the 192.x.x.x
scope. The phone would then see the 10.1.200.x address and all of the above
options from the DHCP server. It would check option 130 as above and compare
its address with the RTC address and should be happy. Next it would contact
the TFTP server for the boot code and then contact the RTC to register. At
that point it should work.

Hmmm!I don't know. If the phone receives an offer of a 10.1.200.x address
and a 192.168.1.x address and accepts the 192.168.1.x address is the hang
due to the fact the phone now has 192.168.1.x as an address and it can't see
the TFTP server or RTC addresses which should be 10.1.200.x addresses. I
would think though it should reject the 192.168.1.x address and try again
until it gets a 10.1.200.x address.

Anyway I'll ask around for ideas.

02-19-2004 03:22 PM

Re: Mitel IP System DHCP Issues
The sequence in the first reply sounds correct. We've put in a number of the
Mitel 3300 but usually have the server DHCP on VLAN1 and use the 3300 as the
DHCP on VLAN2. I can see the phone getting confused when it reboots and
request an IP address on VLAN2 put gets a response from VLAN1, even if it
isn't a valid address. You might want to reconfigure the network so that the
300 is providing DHCP to VLAN2 for the phones. You know what they say Keep
it Simple.

danramirez 05-06-2009 01:53 AM


Did you finally manage to work your Mitel ICP over Allied Telesyn Rappier Switches using the Helper command??

I tried the Helper command but never made it to work, I had to use the ADD BOOTP RELAY=<IP of my DHCP Server> instead.

How did you make it to work with the Helper??? What port(s) did you specify, 67, 68????



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