We would like to enable QoS for voice traffic for all of our phones. I have come to realize there are many ways to accomplish this, and I am hoping someone can point me to the most simple way / best practice.
Please see the attached topology diagram.
We have ShoreTel phones connected to two different HP switches running 16.X firmware. These phones are all connected to the "Phones" VLAN on UNtagged ports, and no computers are connected to the phones (dedicated run for each phone). We don't currently need QoS on any other traffic on our LAN.
EDIT: Note that our phones are configured to only boot and request DHCP ONCE. In many environments, the phone does an initial boot, pulls down the correct "phone" VLAN from a tftp server, then reboots and tags its traffic on the designated VLAN. Because we have dedicated cable runs and switch ports, this is unnecessary, so our phones only boot once, and into the correct VLAN.
From my understanding, these phones can automatically set their own DSCP values.
Questions:
1) Does the "voice" VLAN command even do anything in our environment where the phones are all on untagged ports? When would the "voice" command be used?
2) The page here suggests that I only need to use a single global switch command and everything will work correctly. "qos type-of-service diff-service" Can anyone comment on this, given our toplogy, if this is indeed the only thing we will need?
3) Do I need to specify a VLAN qos policy (DSCP) for the Phones VLAN if I enable "diff-service" as the global QoS on the switch (above question)? Would enabling it have any effect for us, and if so, what effect would it have? I know VoIP phones have a number of different traffic types and only the actual voice data needs QoS applied (and, that is the desired behavior as well).
PS: We also have a handful of phone devices (switches, servers, etc) that do touch some of the voice data, but I'm not sure if they automatically set DSCP values or not.
4) How would the "qos trust" apply to our situation? I know this is applied per port, and currently the trust mode is "Default" for all ports. Default is "Trust 802.1p priority and preserve DSCP or IP-ToS." This sounds sufficient for our usage?
At the end of the day, we would like to use any automatic configuration possible with our phones and don't need to customize anything.
Can anyone offer advice on the easiest way to setup our system?
Thank you kindly in advance!