Voice & Data VLAN - DHCP Query

[darylramharack]

Good Day,

I'm a bit new to networking and have a question related to enable voice and data vlan on the same switchport in access mode.

Can we have DHCP enable for the data vlan alone and not the voice vlan? Want to assign address manually for the voice network. Or does both vlan need to use DHCP if using the same switchport

[Joseph W. Doherty]

Well if Cisco device and Brand X both support LLDP (which for any somewhat recent equipment should be true for either - but again, we don't know the physical equipment being used [do we?]).  That said, I don't recall (?) LLDP being quite as "nice" as CDP, so unsure it's safe to say they "are same".

[Joseph W. Doherty]

Well there is one major "gotcha".

When you create a voice VLAN, its packets are tagged.  So, the VoIP phones would need to be able to accept and transmit tagged packets.  Also, the data VLAN device would be connected to the VoIP phone, which is some cases, becomes a bottleneck for the data device.

When sharing a port for data and VoIP, normally QoS for the edge port is a "must", so voice packets are not delayed by data packets.  Further, some vendors recommend only having half as many data and VoIP devices, per VLAN, on the shared port VLANs.  (Personally, with correct QoS, I don't see this recommendations as hugely important.)

Other than that, from the VLAN and SVI perspective, it's still two VLANs with two SVIs.

[darylramharack]

Thanks everyone for the feedback...much clearer now.