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ProCurve QoS on untagged/tagged VLAN Ports

James Godfrey
Occasional Contributor

ProCurve QoS on untagged/tagged VLAN Ports

We have a network with 3 VLAN's and use ProCurve switches throughout.

Our edge switches will need to use 2 VLAN's simultaneously (1 Data and 1 Voice) using the same uplink to our core network switch. To achieve this we hope to use a combination of untagged and tagged VLAN's.

Ports on the edge switch which require voice will be tagged (VLAN-106). All other data ports will be untagged (VLAN-101).

The fibre uplink will be both tagged for voice (VLAN-106) and untagged for data (VLAN-101). This configuration seems to work okay.

We will need to QoS prioritise the voice data on VLAN-106 as a high priority.

The question I need to ask is will the uplink ports that are both untagged and tagged preserve the QoS Priority between the edge and core switches?

Jeff Carrell
Honored Contributor

Re: ProCurve QoS on untagged/tagged VLAN Ports

QoS settings are by default carried thru on vlans that are configured as tagged...its part of the 802.1Q vlan standard...

so for your voice vlan-106, if you have QoS settings on the vlan itself on the edge switches, as long as the switch-to-switch links for vlan-106 are tagged all the way thru the network, those settings will pass thru to the core switch and thru to other edge switches just fine...

best practice for QoS settings is to have them configured as close to the edge as possible, so that the QoS functions get processed as quick as possible in each edge switch...

more info than required for your question:

there is another consideration as well, depending on the actual switch models/brands, the QoS processing in the actual hardware queues of a switch is a depending factor...ie, some switches have up to 8 queues (to match the QoS priority settings of 0-7) and some switches have 4 or 2 queues...this becomes important when you look at the end-to-end QoS processing (like phone on one end of the lan, and the phone-srvr on the other end), and you have more vlans being configured for QoS...settings like QoS pri 7 and 6 sometimes get the same processing in a switch that only has 2 or 4 queues....again for your config this is anecdotal info only...

finally, my own personal design preference is to only tag all links between switches...that way i can configure things like QoS later without worrying about reconfig of the untag/tag, and someone can't simply disconnect an uplink and plug in a hub at that point in order to sniff traffic...