IP phone +cisco switch

Hi Experts,
Iam trying to configure both voice and data vlan on cisco switch 6500.
The ip phone I use is Nortel 1150 E
I had tried only voice in one switch port, the config is below
interface Gigabit Ethernet x/x
 switchport
 switchport access vlan  20(voice vlan)
 switchport mode access
 no ip address
 spanning-tree portfast

Voice Vlan configuration is as below

interface Vlan 20
 ip address 10.172.0.1 255.255.252.0
 ip helper-address  <Dhcp address>
Nortel ip phone (Voice ) is working fine on this port without any issues.
On this ip phone when I login to check the ips it is showing as
set ip -->10.172.0.101
mask-->255.255.248.0
gateway-->10.172.0.1
but the phone is working fine.

Now I disconnect this port which is working and On another port I configured both voice and data the configuration is as below
interface GigabitEthernet z/z
 switchport
 switchport access vlan 10 (Data vlan)
 switchport mode access
 switchport voice vlan 20( voice vlan)
 no ip address
 spanning-tree portfast
end

after this when I connect my laptop and ip phone only data is working not voice.

But when I login to the ip iphone to check if it takes the ip ,

I see as below
set ip -->10.172.0.101
mask-->255.255.248.0
gateway-->10.172.0.1.

But the ip phone gets stuck in dhcp hung state.

1)Is there any thing I need to change on the ip phone ?
2)Is this the  cisco switch config issue.

Advice please

phoenix26Asked:
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scott30134Commented:
Hi phoenix26,
   I've never used the Nortel 1150 E phone, but looking at your configs, it appears it is using the switchport access vlan which you have labeled as voice in the line "switchport access vlan20(voice vlan) on the first interface instead of the switchport voice vlan.  The second interface you have shown looks more like what is typically used where you have "switchport access" and then your data vlan listed and "switchport voice" and your voice vlan listed.  Here's where it seems you are having an issue.  Cisco uses Cisco Discovery Protocol (CDP) to discover if it is a phone or not.  It appears that the Nortel phone doesn't support CDP and is therefore identified as a data device and assigned to the swichport access vlan instead of the switchport voice vlan.  I'm not sure what type VOIP system you are using, but it is obviously on the access vlan if the phone worked on the first interface.  The solution I suggest if the Nortel phone doesnt support CDP is to either keep it on the same VLAN as your data (if you don't have many phones) or get phones that support CDP.  If this doesn't work for you, let me know what type VOIP system you are using.  So, for your questions you asked:
1.  Look for any setting that says anything about CDP.  I don't think you'll find anything because what I'm looking at looks like the phone doesnt support CDP, so if it doesn't have any setting like that, there is nothing to change on the phone.
2.  The cisco switch config is the reason it works on one port and not the other, but it appears there are more factors in play here.
Let me know if this helps.  Good luck!

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phoenix26Author Commented:
Hi Scott,

1.We  already bought  nortel phones.
2.dhcp scope is seperately defined for voice and data.it is a win2k dhcp server.
3.Apart from dhcp there exists a call manager which i believe is working fine.
4.I did this configuration as per nortel  recommendation for cisco switches  -
 switchport access vlan 10 (Data vlan)
 switchport mode access
 switchport voice vlan 20( voice vlan)
 no ip address
 spanning-tree portfast
end.

Every other parameters were taken care off as per nortel recommendation for cisco interoperability.
but still when the port is configured for voice and data , data is working fine and voip phone returns
DHCP server unreachable.

Please advice a solution.



lrmooreCommented:
Do you have option 132 (VLAN ID) set to 20?
According to this document, you have to tell the phone what VLAN ID it is supposed to use for voice with DHCP. It is specific to 1140E, but maybe same issue with yours?
http://www.michaelfmcnamara.com/files/ClientsInteropCisco_L2_1.1.pdf
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lrmooreCommented:
More information on the DHCP options, specifically for Nortel phones
http://blog.michaelfmcnamara.com/2007/10/dhcp-options-voip/
phoenix26Author Commented:
Hi moore,

Its all done.But still facing the issues?

Any solutions
lrmooreCommented:
Can you manually configure the phone with the voice vlan ID?
scott30134Commented:
Obviously, your phones are being picked up on the access vlan as if they were computers or a device that doesn't support CDP.  Can you configure the phone so that its in the voice VLAN?  With cisco phones this is done automatically with CDP. I'm not sure if CDP will work with your phones, but I've used siemens phones before which do not support CDP, and I manually configured them with the correct voice VLAN to make them work.  This could also be done with DHCP.
phoenix26Author Commented:
Hi ,

Thanks for your responses.
The thing is that i already pointed that -please see  below
set ip -->10.172.0.101
mask-->255.255.248.0
gateway-->10.172.0.1.
 in the ip phones when i configure them for voice and data,
meaning it is taking the voice vlan ip .but still they enter dhcp unreachable state.

Further one more doubt for voice vlan I configured subnet mask as follows-255.255.252.0

"interface Vlan 20
 ip address 10.172.0.1 255.255.252.0"

But when i see them in the ip phones the mask is shown as 255.255.248.0.why is it so?

Please eloborate



scott30134Commented:
Okay, well... two things are puzzling me.  One, you shouldn't need the "swichport mode access" command in there.  That just makes the port act as an access port exculsively with no exception, which could be a problem.  Two, on the port you said worked, it looks like there was a mistake in it because you have "switchport access vlan  20(voice vlan)".  I would think it should be "switchport voice vlan  20(voice vlan)".  If you put switchport access, it doesn't matter whether it is a computer or a phone that doesn't support CDP, it will get assigned to that VLAN.  That's what made me think that your phone didn't support CDP and was getting assigned to the right VLAN because it was configured as switchport access instead of switchport voice.  Follow me?  
Do you have a DHCP server on both VLANs?  If you do, what is the subnet mask they each are assigning?

phoenix26Author Commented:
in switch  are having subnet mask 255.255.252.0  for voice vlan but iam repeatedly seeing in the ip phone as 255.255.248.0

why is it so?

phoenix26Author Commented:
scot ,

can u  say what change i need to do on the switch?

thx
lrmooreCommented:
Set the subnet mask on the vlan interface to match that of the DHCP scope.  If the phone gets a mask of 255.255.248.0 then it is getting it from DHCP. Either change the scope to match the switch, or change the switch to match the scope.
One of the links above talks about the phones getting stuck in DHCP mode if you don't have option 128 in the DHCP scope options.
scott30134Commented:
You don't have the IP range or subnet of your data VLAN posted.  However, if 255.255.248.0 is your subnet for your data vlan, this confirms everything I've been saying that your phone is taking the data vlan.  Can you post your dhcp settings for both VLANs?  I think that would help us see what all is going on there and what might be missing.
phoenix26Author Commented:
Hi expert,

It has nothing to do with datavlan as data vlan subnet is 255.255.0.0

Any other possible reason?

Thx
scott30134Commented:
Okay... well, the question is, where is it getting that 255.255.248.0 subnet if not from DHCP.  Obviously, it's NOT from the data VLAN if what you say is correct that you have the data vlan subnet set to 255.255.0.0.  However, without seeing your DHCP config for both the data and voice VLANs, I am leaning toward what lrmoore posted last, that its getting it from DHCP.  Make sure your voice vlan in the switch is the same as your DHCP scope.  Is it possible you have your DHCP server configured for a 255.255.248.0 subnet?
Here's the thing:  it's either getting that subnet from DHCP or it is statically configured in the phone, so I would rule out the statically configured first - double check your manual configuration in the phone. If it's not a static setting in the phone, double check the DHCP server.  If it's not the DHCP server, is it possible you have inadvertently have two DHCP servers running on your voice VLAN?  A server and a router running DHCP perhaps?  That could cause problems like this.
phoenix26Author Commented:
Hi Scott /experts,

Now this issue got resolved ,the problem was in the dhcp server--- for voice only the nortel parameters were defined,but for data it was missing.so it was added for data also.After that "Binding" change in dhcp server the ip phones started working.

But there are still issues.When i do the same changes to all ports in access layer switches ,only data is working ,ip phone hangs in "starting dhcp" state.

To brief now after the dhcp changes ip phones work from core switch and not from access or distribution switches.

Any specific changes needs to be done on distribution and access switches?

Advice please

InvokerLeirCommented:
Just to throw another kink into the whole thing, since they didn't really show the data subnet, the poster indicated that his (private class A) subnets were:
VoIP:  10.172.0.1 255.255.252.0 or 255.255.248.0
and
Data:  ?.?.?.? 255.255.0.0
Going back to the routing/networking portion of the equation here, unless he changed his first two octets to something other than 10.172.x.y, the subnets would overlap and cause some fairly aggravating routing problems.
phoenix26Author Commented:
satisfactory
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