Voice Vlan Configured as an access port. DHCP option issue and Qos Config.

[karinatan]

Hi,

I am configuring catalyst 9300 switches for a customer and they are adamant to connect their phones on separate independent ports and insist on configuring he dhcp pool for voice vlans in the Switch itself.

What would be the best config for the phones(Unify Openscape Desk phones)? 

How will the dhcp options work in this case?

Will I be able to prioritise voice traffic with Qos commands?

Please Help

Thanks

Joseph.

[M Talha]

Hi karinatan,

Firstly enable DHCP for IP Phones in Openscape business, secondly reserve a small range of IP addresses while configuring DHCP in your openscape business system. Now follow these steps.

#int vlan 10

#ip add 192.168.0.5 255.255.255.0   <--- (define your voice subnet accordingly)

#ip helper-address 192.168.0.1 <--- (Ip address of your unify openscape LAN segment)

#description VOICE

#end

#int gig 0/1

#switchport mode access

#switchport access vlan 5 <-- Vlan 5 represents your data vlan here for example)

#switchport voice vlan 10  <-- Vlan 10 represents your voice vlan here for example)

#end

In this manner your phones and PC's will work on same switchport, secondly you won't be needing QOS as they will work fine without any hassle. 

[karinatan]

Hi  M Talha,

Thanks for your response. Yes it is possible to have DHCP set up in the phone system. But it can only do one scope.

I have got 9 voice vlans altogether.

Any other ideas?

Thanks

Joseph.

[Mark Malone]

Hi
Do these phones mark EF at the source if they do the 9ks will honor it anyway and carry the marking through , you can still use auto qos on the 9k too for the phone ports if required but the 9k should trust DSCP by default

auto qos trust dscp i would use as there not Cisco phones that will generate a class and policy map , hers the link to 9k auto qos
refer to this section

Example: auto qos trust dscp
https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst9300/software/release/16-5/configuration_guide/qos/b_165_qos_9300_cg/b_165_qos_9300_9500_cg_chapter_00.html


i agree its a waste of ports having phones and pcs separate but if thats what they want , is there no way to marge these 9 voice vlans to reduce the amount of dhcp pools 9 ?? why is there 9 separate voice vlans ?

[Deepak Kumar]

Hi,

You can assign only one Voice VLAN per port. Can you explain a bit more about the network? Is it an ISP network? I never have seen 8 or 9 voice VLANs in my life. I think network design is not correct if it is not ISP. 

How to assign VLAN on port:

Interface gig X/X/X

switchport mode access

switchport access voice vlan X   --> Voice VLAN

switchport access vlan Y -->DATA VLAN

spanningtree portfast 

Yes, If you have multiple VLANs and many users then it is advised to enable the QoS on 9k. I am not sure about the phones is capable to mark QoS. If yes, then you can use the Switch's Auto QoS configuration. 

Regards,

Deepak Kumar

[M Talha]

Dear Karinatan,

If you have 9 voice vlans than all you have to do is enter voice gateway ip address i.e your UNIFY system IP while configuring your phones, so that these phones gets registered on UNIFY server and start working. In IP phones you have option like this 

IP add : 192.168.X.X

Mask : 255.255.255.0

Subnet GW: 192.168.X.X

VOIP Gateway : 192.168.X.X

Once you enter these phones will register and start working

Regards,

Talha

[Deepak Kumar]

Hi @M Talha ,

as his client is configured nine VLANs for voice then you can imagine how big is the network?  Do you think, manual TCP IP process will easy?

Regards,

Deepak Kumar 

[M Talha]

@Deepak Kumar 

It won't be easy as you have to configure each phone manually but that is the only way out. I have came across this scenario at a financial institution which consist of thousand phones almost and each floor has different vlan for voice. But its been done in stages not at once so i don't have any overhead to complete the task at once.

Regards,

Talha

[Deepak Kumar]

Hi,

Have you learned about the DHCP option 150 & 66?

Regards,

Deepak kumar

[M Talha]

@Deepak Kumar 

I knew about these DHCP options but in my scenario there was no option of DHCP server as client insisted to stick on manual configs.

Regards,

Talha

[karinatan]

Hi,
I just want to avoid the manual configuration, that is why I am trying to get this option 43 working.
Is there any other solutions available?

Thanks
Joseph.

[M Talha]

If its possible for you setup a DHCP server which can do the job quite well enough for voice vlans and data as well.

Regards,

Talha

[Deepak Kumar]

Hi,

Which Voice is implemented in your office? Can you check again for the required DHCP option? Because Option 43 is using for the Wireless AP to get WLC IP address (most of the vendors). 

Regards,

Deepak Kumar

[karinatan]

Hi,

We are using Unify(previously Siemens) handsets- Unify Open stage Desk phones.

Thanks

Joseph. 

[Deepak Kumar]

Hi,

Use the below guide:

https://wiki.unify.com/wiki/VLAN_ID_Discovery_over_DHCP#DHCP_Option_43_tags

https://wiki.unify.com/images/c/c7/OpenStage_Provisioning_Interface_Developer%27s_Guide.pdf