Mitel DHCP disaster

G'day everybody!

I'm currently facing a tough challenge. We have built the following: Mitel 3300 ICP with 5212 IP phones on an HP ProCurve layer 3 PoE switch. On the switch, we made two VLAN's (VLAN 1 for data, VLAN 2 for voice), of which the second has tagged ports for QoS. The PC's are physically linked by the phones, acting as a hub for interconnectivity.

When rebooting the phones, and thus requesting for DHCP scope, this is not functioning (reject 1 thru 10). The PC's do get a correct IP address. After untagging the ports in VLAN 2, DHCP was working properly. This situation, however, is not helping anyway, since tagged ports are necessary for QoS purposes.

Investigation shows that the phones send untagged packets when requesting DHCP, this is fixed in the firmwear of the phones.

Can anyone provide new insights on this please?


Johan, project leader

Reply to
Loading thread data ...

By 'tagged" do you mean 802.1Q tags? (What most switches mean by tagged.) Do you have both vlans going to a single physical port? Usually you can't/shouldn't mix tagged and untagged ethernet frames on the same "wire".

Switch -> phone -> PC ?

Or are you mixing tagged and untagged devices on the tagged vlan?

Can you configure QoS by MAC/IP address or protocol on those switches? Might be a better way that using tags.


Reply to
Carl Zwanzig

Thanks for replying!

Here are the anwsers:

Reply to

Sure it's possible... but it's not a good idea. If nothing else, some systems can't deal with the tag when they're not expecting it.

No, there wouldn't be. I expect it's just acting as a dumb hub or switch.

A couple of things: Don't mix tagged and untagged traffic on the same "wire". If you only have one wire, consider using protocol-based vlans if your switch/router can specify things (not all can). Consider whether you really need QoS out to the desktop. :-)


Reply to
Carl Zwanzig

Does the scope for the DHCP server that is on VLAN 1, have all the options programmed that the Mitel phones need?

We have a similar setup using a HP 2650 PWR layer2/3 switch. The phones boot and as you say, they send out untagged packets for their DHCP request. The request would then go out on the default or untagged VLAN ( which is VLAN

1 ). Therefore its DHCP server will return an IP address to the sets ( as you say it does to the PC's ). What has to be received with the set's IP address are the options required by the sets. Table 44: DHCP server options

DHCP option Information

003 - router address IP address (e.g.

066 - FTP server for gateway/E2T IP address (e.g.

067 - boot file name for gateway See the Technician's Handbook.

128 - (specific) TFTP server IP address (e.g.

129 - (specific) RTC IP address (e.g.

130 - (specific) IP identifier "MITEL IP PHONE"

131 - debug IP address (e.g.

132 - (specific) VLAN ID (32 bit) 0x2

133 - (specific) Priority (32 bit) 0x6

134 - (specific) DSCP value 0 to 63 (32 bit) 0x2e (this is 46 decimal in hexadecimal format)

The sets once they have received the options, know that they are to tag their packets with VLAN 2, what to mark as their priority, where the 3300 is and where the TFTP server is to download their software. The sets at this point drop this intial IP address and send out another DHCP request, but this time they are tagging their packets to VLAN 2. A DHCP server on VLAN 2 ( usually the 3300 ) has to provide a new IP address. Otherwise DHCP forwarding needs to be set up on the HP to send the requests over to VLAN 1, where its DHCP server will have to have a second scope set up to supply separate IP addresses for the phones.

So does any of this help?

Reply to
DPGumby Forums website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.