Prioritizing voice traffic inside the vDS switch for Lync/Skype/sip/dscp values/tagging

[gpalmer1981]

Dear Experts!

I'm posting this today because I have looked and failed to find any content on this subject.  Within ESXi 6.0 and above we have now been blessed with the feature of marking/tagging traffic with either a CoS value or a DSCP value.  I think this is great, however there doesn't seem to be any traffic prioritization for said marked/tagged traffic.  You can allow or deny the traffic which is a good feature but I think what most people will be looking for is the ability to prioritize tagged traffic over everything else.  This is sometimes essential for real-time protocols like sip and rtp which is used by Skype for Business or Lync.

Lets compare with a physical Juniper EX range switch.  Here we setup a filter to detect traffic marked with a DSCP value of 46.  The switch firewall filter then pushes this traffic into the expedited forwarding queue.  So as we can see traffic prioritization is occurring here.  So my question, or discussion is, where is this ability within VMware's vDS switch/dvPortgroup?

Thanks

[npadmani]

Action: TAG will let you do what you want to do in vDS. I have taken screenshot from version 5.5 of vSphere (vDS).

if you refer following networking guide page 110, you get step by step info.

https://pubs.vmware.com/vsphere-60/topic/com.vmware.ICbase/PDF/vsphere-esxi-vcenter-server-60-networ...

[npadmani]

Let me also add following note

vDS is only available via vCenter server. so if you are trying to find traffic filtering or tagging feature in a standalone ESXi host, you will only see Standard Switches which don't offer this functionality.

[gpalmer1981]

Ok so are you saying that just by tagging the traffic with DSCP value 46 it will prioritize the traffic automatically?  Because I dont think this is the case in physical switches.  My question is: once the traffic is tagged HOW can I get the vDS to actually put this traffic into a higher priority queue so it takes higher priority over everything else.

Thanks

[gpalmer1981]

Anyone else want to take a stab at this one?

[adamwiso]

Oh QoS Goodness in Lync - speaking to the choir my friend.

The bottom line is this, DSCP is a L3 construct.  VMWare and the VDS/vDPG only do L2.  I had an interesting discussion with a network engineer @ VMWare and he chuckled he has no real idea why that L3 tagging was included, VMWare only DOES L2!  Your prioritization needs to occur on the physical infrastructure.  If you want to test the traffic in and out of your VMWare ingress/egress points you can use, pktcap-uw --uplink vmnic1 --dir 1 --stage 1 with the appropriate dirs. and stages to see the traffic flow through all your interfaces.  If you want these commands let me know, look to the physical infrastructure my friend.