Configuring DHCP server with Option 150 in core switch

[siddhukaturi1]

Hi all,

Kindly help us on this issue we are unable register IP Phones in new created VLAN.

Issue: In my organization we have voice VLAN which is having subnet of 255.255.255.0(5th floor users) with the range of 10.50.20.11 to 10.50.20.254. Now almost the DHCP pool is full so we need to create one more VLAN for 6th floor users.Some one please help us to configure the second Voice vlan for 6th floor users or is their any other solution is their(Like changing subnet).

I created a New VLAN142 in core switch but when ever I connect IP phone in the 142 vlan it is not registering. Kindly help us please.

interface Vlan142
description "IP_Phones2"
ip address 10.50.22.2 255.255.255.0
ip helper-address 10.50.1.9
standby 1 ip 10.50.22.1
standby 1 priority 150
standby 1 preempt

Thanks in advance.

[Leo Laohoo]

I created a New VLAN142 in core switch but when ever I connect IP phone in the 142 vlan it is not registering. Kindly help us please.

Uhhhh ... Why not create a SECONDARY IP address on the original voice vlan? 

config t
interface vlan <BLAH>
 ip address A.B.C.D <subnet mask> SECONDARY
end

[siddhukaturi1]

Hi Leo,

Thanks for your quick response.

Please check my configuration.

!
interface Vlan140
description "IP_Phones"
ip address 10.50.20.2 255.255.255.0
ip helper-address 10.50.1.9
standby 1 ip 10.50.20.1
standby 1 priority 150
standby 1 preempt
!

Now I need to replace it with below statements ...

interface Vlan140
description "IP_Phones"
ip address 10.50.20.2 255.255.255.0
ip address 10.50.22.2 255.255.255.0 secondary
ip helper-address 10.50.1.9
standby 1 ip 10.50.20.1
standby 1 priority 150
standby 1 preempt
standby 2 ip 10.50.22.1
standby 2 priority 145

Kindly Correct me if it is wrong...(Configuration is in core switch) and Whether it is permanent solution or temporary.

[Leo Laohoo]

ip address 10.50.20.2 255.255.255.0
ip address 10.50.22.2 255.255.255.0 secondary

That's correct. 

The only thing left is to create a new DHCP Option 150 with the10.50.22.0/24 network.

[siddhukaturi1]

Dear Leo,

Thanks for your support.

As per the suggestions form L3 support they suggest the below configuration.(Changing the subnet)

interface Vlan140
description "IP_Phones"
ip address 10.50.20.2 255.255.252.0
ip helper-address 10.50.1.9
standby 1 ip 10.50.20.1
standby 1 priority 150
standby 1 preempt

if I gave the above configuration change in Core switch is their any effect for the existing IPPhones. The same subnet we changed the configuration in DHCP pool.

Leo I am so struggling with one dought that is

We are giving any IP Pools in call manager to recognize the IPPhone.

[Leo Laohoo]

if I gave the above configuration change in Core switch is their any effect for the existing IPPhones. The same subnet we changed the configuration in DHCP pool.

Depends on the phone.  

The subnet of the phone still falls under the same subnet as the new VLAN.  The gateway is the same.  

However, there is an added benefit, for safety sake, to reboot the phones once the new subnet is confirmed to be working.