DHCP Options Mystery

[MitelGuy57201]

Greetings!

I will try to be as descript as possible here but will probably miss something - my apologies in advance

We are running a Mitel 3300 and primarily use aging 3Com (with PowerDsine injectors) and relatively new HP ProCurve POE switches. All the 3Com and HP switches are to be replaced with Cisco 3750 POE switches soon.

We have a Win2k3 DHCP server that has options 128, 129, 130, 131, 132, and 133 set for the DHCP scope of the phones (same options are set on the data DHCP scope).

We are using 5201, 5212, 5215, 5220, and 5224 phones.

All models of phones boot properly using VLAN 2 Priority 6 on the 3Com and HP switches.

The 5212 (fact) and suspect 5224 phones (unknown at this time) do not boot up properly on the newly configured Cisco 3750 that is connected to a HP ProCurve switch. They boot with VLAN 2 Priority 5. The are getting an IP address in the proper range (as does the computer we have connected to the PC port on the back of the phone).

If we change priority to 7 in the scope options, the 5212 pick this up and boot up VLAN 2 Priority 7 as one would expect (on the Cisco 3750) but when we change Priority back to 6, they boot with a Priority of 5?!?!

The software version on the controller is 7.1.3.4_2 (I know... way outdated) but we have no plans on updating this as we may very well be moving to an Avaya system in the near future.

The trunk port on the Cisco (that connects to port 21 on the HP) is configured as such (VLAN 1 = data, VLAN 2 = voice):

interface FastEthernet1/0/1
switchport trunk encapsulation dot1q
switchport trunk allowed vlan 1,2
switchport mode trunk
switchport nonegotiate

and the access ports (remaining 47) are configured as such:

interface FastEthernet1/0/2
switchport mode access
switchport voice vlan 2
mls qos trust cos
spanning-tree portfast

Port 21 on the HP (that the Cisco 3750 is connected to) is configured in such a fashion:

vlan 1
name "Data_VLAN"
untagged 1-23
ip helper-address 10.2.2.20 (NOTE: Win2k3 DHCP server)
ip forward-protocol udp 10.2.2.20 netbios-ns
ip forward-protocol udp 10.2.2.20 netbios-dgm
ip address 10.2.2.10 255.255.254.0
tagged 24

vlan 2
name "Voice_VLAN"
untagged 24
qos priority 6
ip helper-address 10.2.2.20 (NOTE: Win2k3 DHCP server)
ip forward-protocol udp 10.2.2.20 netbios-ns
ip forward-protocol udp 10.2.2.20 netbios-dgm
ip address 10.2.201.1 255.255.255.0
tagged 1-23

I think I have covered it all - again, sure I missed something ;-)

Scratching my head on this one... Thoughts??

Many thanks in advance!
MitelGuy57201

 

[kwbMitel]

I have seen Cisco Switches provide Priority 5 before and have no explaination as to why. 5 is probably sufficient in the whole scheme of things.

You should not have option 131 configured except for troubleshooting.

**********************************************
What's most important is that you realise ... There is no spoon.

 

[MitelGuy57201]

Thanks for the response!

Option 131 is only set in the scope options for the phones - it points back to our OPS/Ent Manager server... Is this not necessary?

I guess in my post I incorrectly stated that both scopes were set up the same - my bad.

 

[kwbMitel]

Option 131 invokes the IP phone Analyser tool which can generate a lot of unnecessary traffic. It is primarily a troubleshooting tool. I would be far more concerned about this option being enabled than with having priority 5 instead of 6.

**********************************************
What's most important is that you realise ... There is no spoon.

 

[JimHilton]

To my eyes, you've to 2 matching sub nets on the same VLAN. Isn't that a nono?

 

[stickymicky27]

How come you do not have option 125?... but for phones to work you should only need options 125, 128, 129, 130, 132, 134

Jim... he doesn't have 2 matching subnets? 1 = 255.255.255.0 other is 255.255.254.0

But in saying that I have always configured the VLANs with the same subnet... i.e.

Vlan 1 = 10.10.10.0 Sub: 255.255.255.0 Gate: 10.10.10.1
VLAN 10 = 10.10.20.0 Sub: 255.255.255.0 Gate: 10.10.20.1

Then you should used the cisco 3750 as your gateway with a route everything to your router, this is the reason you have a L3 switch?

Let me know if you want to know what each option does...

 

[stickymicky27]

Edit:... Im going out but i think you need to change your system totally as the cisco 3750 allows you to mange to vlans on the same port... this is how i have mine configured... this enables you to plug either a phone or PC into any port of the switch!