5312 IP Phones and DHCP

[KirkM]

Hello folks...very first post here.

I need someone to explain the Discovery DHCP Option 125 to me.  More importantly I would really like to understand why all of my older Mitel IP phones seem to have ZERO trouble getting a DHCP address yet this phone, unless plugged directly into an ANCIENT fastethernet switch, cannot seem to pull something so basic.

My environment...nothing as fancy as a third party DHCP Server here...my Mitel phone system IS the DHCP Server...  Now, I'm trying to mothball, as I stated, a 10 year old HP FastEthernet switch and move my phones to a new Ubiquiti.  But it doesn't matter...Ubiquiti...Dell...Cisco...this phone simply will not pull an address.  Static works great.  Can someone please help?

Why it matters I'll never know...but here is the 125 configuration on the DHCP server: id:ipphone.mitel.com;sw_tftp=192.168.101.10;call_srv=192.168.101.10;vlan=6;l2p=6;dscp=46

Any thoughts?  Thanks!

[acejavelin]

We have several schools with 5312 phones... Most are using option 125 directly from the Mitel controller's DHCP server with no issues on gig switches, mostly Cisco SG series or Aruba. The remaining are using option 43 from Windows or "other" customer owned server.

What is the version of your PBX and firmware of the phones?

[Tech Electronics]

KirkM,

It may be that the switch is not providing the LLDP or CDP information fast enough for the phone to recognize it.

Look to see if you have spanning-tree portfast turned on the port the phone is plugged in to so it doesn't go through the listening and learning states. Personally I really think this should always be turned on for ports where IP Phones would be plugged in.

Thanks,

TE