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DHCP LQ2Vlan Statement for Multiple Voice Subnets

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TelcoJohn

Technical User
Jan 22, 2013
20
US
I am working on a VOIP implementation plan for a existing building. This building has a single class B data network, but I would prefer to cut the voice network into five class C subnets (one for each data closet). The problem I am running into is the single DHCP scope for the data network and the LQ2Vlan option. It seems to me that I could only have one voice subnet per data subnet due to this option string. I posted my standard DHCP scope string and switch port configs below for reference.

MCIPADD=IP address,MCPORT=1719,HTTPSRVR=IP address,L2q=1,L2qvlan=141

interface GigabitEthernet1/0/33
switchport access vlan 101
switchport mode access
switchport voice vlan 141
priority-queue out
mls qos trust dscp
spanning-tree portfast
spanning-tree guard root

Is there a way to do what I am thinking? Have a single DHCP scope provide one of any optional scopes? I was thinking of removing the LQ2 statement altogether and manually entering the VLAN ID on the phones, but with 800+ phones I would prefer not to do this.

Any thoughts would be appreciated.
 
I'd seriously reconsider the idea of statically assigning the van I'd. Don't do it. I'be just cut over a site where someone had done just that for 60 phone. Don't do it it will only ever haunt you in the future.

As I understand it, I think you will struggle using dhcp for vlan selection in the environment you have. LLDP might offer a solution.

Possibly the best solution is to see if the data team can split the data lan into multiple smaller subnets. A /16 network is really too large for a single segment; we try to limit our segment size to a /24 or /23. It isn't always possible... but its an aspiration

Take Care

Matt
I have always wished that my computer would be as easy to use as my telephone.
My wish has come true. I no longer know how to use my telephone.
 
It looks like LLDP is going to be the answer to our problem, we start testing today. Ill post the results in case others see this post.

Cheers
John
 
The LLDP configuration was successful. Pretty simple and gives me greater control at the switch level to change VLAN assignment. This allowed us to remove the LQ2 entry from the DHCP scope completely and just rely on LLDP. You can enable LLDP at the global level by issuing "LLDP run" command.



 
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