9608, DHCP not working

[chaunymony]

Hey all. So we have a little issue. I have 4 sites, IP500v2's at 7.0(232702). 9608 phones. Cisco 2960 switches and running DHCP through a MS server. We set the VLAN off the data scope, then the rest of the IP addresses and such off the voice network scope, option 242 of course. First phone or two or 3 boot up, grab the VLAN, grab an IP address then upgrade and proceed to the login screen like they should. After that other phones wont grab the VLAN, or some may grab the VLAN but then not grab the IP addresses. If I static the phones, everything works fine.

It's almost like we have 3 issues. One phone will grab the VLAN and IP lease and everything works fine. Another won't grab the VLAN but if we static the VLAN it will then get the IP lease and work fine. Then we have one that may or may not grab the VLAN, so we will static or won't depending on conditions, but then won't grab a lease.

We are pretty stumped on this. I have had plenty of DHCP scopes set this way but off of HP switches and it has worked fine so I know that our DHCP setup is correct. My thought is our issue lies in the cisco switch but not sure. Anybody shed any light on this?

ACSS-SME
ACIS-SME

 

[kholladay]

If the Cisco supports LLDP it is a far better way to go.

Here is how I would do it on a 3560 24 port
lldp run
interface range gigabitEthernet 0/1-24
switchport mode access
switchport voice vlan NN (where NN = the VLAN tag for voice)
switchport access vlan NN (where NN = the VLAN tag for data, probably 1)
spanning-tree portfast

Then you don't need any of that junk in your data DHCP scope as the switch will tell the phone to go to the voice VLAN and bypass the data VLAN completely.

Kyle Holladay / IPOfficeHelp.com
ACSS & APSS Avaya SME Communications
APDS Avaya Data
MCP/MCTS Exchange 2007/2010
Adtran ATSA, Aruba ACMA

"Thinking is the hardest work there is, which is the probable reason why so few engage in it." - Henry Ford

 

[AACon]

Because I'm biased I'm going to say its the cisco switch and suggest an extreme networks switch.



-Austin
ACE: Implement IP Office

 

[kholladay]

Sorry...that assumes you are using a DHCP server on the voice VLAN. If not you'll need to setup a DHCP relay agent on the switch.

First make sure the port to which the DHCP server is on is ONLY part of the data VLAN.

configure terminal
service dhcp
interface vlan NN (where NN is the tag of the voice VLAN)
ip helper-address <address> (where <address> is the IP address of the DHCP server on the data VLAN)


Kyle Holladay / IPOfficeHelp.com
ACSS & APSS Avaya SME Communications
APDS Avaya Data
MCP/MCTS Exchange 2007/2010
Adtran ATSA, Aruba ACMA

"Thinking is the hardest work there is, which is the probable reason why so few engage in it." - Henry Ford

 

[Bas1234]

And set the Gateway of the DHCP server to the Layer3 switch or do a route add in a dos box.

Say data VLAN is 192.168.1.0 and Voice is on 192.168.42.0
And 192.168.1.x is your Layer3 Cisco switch.

route add 192.168.42.0 mask 255.255.255.0 192.168.1.X -p

___________________________________________
It works! Now if only I could remember what I did...

Dain Bramaged (Avaya Search tool

http://tinyurl.com/bas1234

)
______________________________________

 

[chaunymony]

Data is on VLAN 10, we were thinking that was where the issue was due to the phone not looking at VLAN 10 for the VLAN 11 (voice) tag.

ACSS-SME
ACIS-SME

 

[kholladay]

If your switch has

switchport mode access
switchport access vlan 10

then it will look at VLAN 10

4/5 times the issue you are reporting (manually addressing works but DHCP doesn't) is the result of having both VLANs assigned to the port to which the DHCP server is connected. As with any switch where DHCP requests are being routed from one VLAN to another the DHCP server must be connected to a port that is assigned only to the VLAN in which that server's IP is native. In your case VLAN 10.

You can tell if the phone is getting the information from DHCP because it will sit there and count up DHCP waiting time and flash VLAN 10 which means that it got the VLAN information from the data scope but cannot get to the voice network.

Kyle Holladay / IPOfficeHelp.com
ACSS & APSS Avaya SME Communications
APDS Avaya Data
MCP/MCTS Exchange 2007/2010
Adtran ATSA, Aruba ACMA

"Thinking is the hardest work there is, which is the probable reason why so few engage in it." - Henry Ford