EOS QoS for Voice VLAN - setup and config ?

Hi Everyone,

I have tried to go through existing GTAC KBs and HUB entries, as well as config guides ~ I am not quite sure that the information and my goals are matching properly.

#1 Reference GTAC: https://gtacknowledge.extremenetworks.com/articles/How_To/How-To-Priortize-All-Traffic-in-a-VLAN-by-...
#2 Reference GTAC: https://gtacknowledge.extremenetworks.com/articles/Solution/Policy-setting-up-QoS-for-voice-over-IP-...
#3 Reference GTAC: https://gtacknowledge.extremenetworks.com/articles/How_To/How-To-Configure-LLDP-MED-Network-Policy/
#4 Reference GTAC: https://gtacknowledge.extremenetworks.com/articles/How_To/S-Series-Quality-of-Service-for-VoIP-Traff...
#5 Reference HUB: https://community.extremenetworks.com/extreme/topics/g_d_c_b_a_series_f_w_6_03_use_of_the_lldp_med_n...

The objective is simple - create a QoS policy that would prioritise all voice traffic in the network over all switches .

Data vlan = 1
Voice vlan = 2

This is what I have enabled on the EOS switches:

set lldp port status both ge.*.*
set lldp port tx-tlv all ge.*.*
set lldp port trap enable
set lldp port med-trap enable
set lldp port network-policy voice state enable tag tagged vid 2 dscp 46 cos 6 ge.*.*
set lldp port network-policy voice-signaling state enable tag tagged vid 2 dscp 44 cos 5 ge.*.*

As I understand it - based on reference 3 and 5, I am now sending the LLDP-MED DSCP and CoS values to the phones in the network - this is working.

My question is, should I then configure a policy (ref. 1 & 2) to ensure that the phones are prioritized over the network or is this already accomplished with the LLDP policy ?

As always, I appreciate any advice,


4 replies

Userlevel 4
the EOS switches ABC-SecureStacks and S/K-Series have an COS trusted mode, means that if we receive an q-tagged priority bit 0-7 we will automatically map the Priority queue on the outgoing port. This means if you have between Phone and switch and switch to switches 802.1q.trunks with tagged packets you not need to configure any additional commands to have Voice running in the higher queues. Voice should be COS-5. You might need to consider to change the queuing mode to Strict-priority on ABC switches.
C5(su)->set port txq *.*.* 0 0 0 0 0 100 , and disable flowcontrol global ensure that you not drop packets per flowcontrol.
Userlevel 3
Hello Dewald,

lldp is just an informative protocol.
At least you need to enable cos on the switch:

set cos enable

But I would recommend you to not relay on default cos but to implement your own QoS regulation.

Kind regards
HI ,

Thanks for the replys.

1 - the LLDP-MED policy to my understanding, sends DSCP/COS marking to any LLD-MED enabled device, in this case the phones as they exists in VLAN 2.

2 -@Bastian, If I understand you correctly, you are saying that due to the LLDP-MED policy, the phones are now egressing the ports with DSCP/COS markings in the 802.1q TAG header - Due to the default COS trust on ABC/SK switches, the DCSP/COS marking will be adhered to across all switches in the network (due to voice tag being on all switches in whole of network).

3 -@Bastian, what would the strict adherence achieve ? I was under the impression that CoS 0-7 is default on switches and with a CoS of 6 (RTP/VOICE 802.1p mark as per EWC) it would be the same and prioritized across the network. Or am I missing something ?

4 -@Christoph - thank you. Is this disabled by default ? Based on my already enabled LLDP policy, would enabling the CoS then prioritize the traffic ? Would there be any other commands to ensure the voice vlan - all traffic in vlan 2 - be prioritized ?
The remainder of the network is flat, therefore I only need to have higher priority on Voice. If not enabled, the CoS for the network would be 0 if I am correct ?

Thanks 🙂
Userlevel 4
-the LLDP-MED option will configure the Phone as you mention,

-the Phone now send tagged packets with an COS and DSCP value as defined.

-the EOS switches per default will process COS values as trusted and will map that to an COS index (show cos settings) most switches has 8 TXQs versus the EWC use only 4 TXQs which cause that Voice has been placed in the highest queue on the EWC see the mappings, will also work on the switch.

-as long as you use the default COS index priority queuing happen. Only for new COS index you need to enable COS

-strict queuing ensure that the Voice queue will be processed in time, WRR default queues can cause that lower queues will be process.