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QoS Prioritization for VoIP using DiffServ
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Hello,
I am trying to understand and configure QoS prioritization for VoIP using DiffServ (46).
I find this configuration very counter-intuitive, but we have about 50 of them, so I have to figure this out.
1st question - is it enough to simply go into DSCP to queue mapping and change the EF (DSCP 46) to queue 3? Does this mean that all traffic marked with the DSCP 46 EF header will be in the highest queue and therefore takthe mose t priority? Incidentally, I don't understand why any DSCP attributes are configured under CoS as CoS is technically for L2 and DiffServ (DSCP) is strictly L3 (this is one area that is very counter-intuitive to me), but as long as I understand HOW to do it, I guess this doesn't matter.
2nd question - If my above statement regarding the DSCP to queue mapping is correct (all you have to do is change EF (DSCP 46) to queue 3), why would anyone create a policy configuraton, mapping a policy attribute (queue 3) to a class (Service Type = DSCP ef) as described in the following Netgear KB: "https://kb.netgear.com/21757/How-do-I-configure-differentiated-services-DiffServ-for-Voice-over-IP-V..."?
Much of this KB doesn't make sense either becasue you can't assign a queue AND mark a DSCP value as it says, but I'm assuming this is due to the model and firmware differences, etc... Unfortunately, I find there are errors in most of the KB articles I've found thus far, and it is difficult to find the exact information I'm looking for (for this particular switch). Hoperfully someone can help me out here...
Thank you!
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I apologized for the late response. 😞 I forwarded your recent post to the higher tier of NETGEAR Support and just got a feedback today.
As per the higher tier of NETGEAR Support, based from the attachment, the configuration looks fine on AF31 and EF46 for DSCP.
Regards,
DaneA
NETGEAR Community Team
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Re: QoS Prioritization for VoIP using DiffServ
Hi @RI-IT,
Welcome to the community! 🙂
I inquired your post to the higher tier of NETGEAR Support and just got a feedback today. As per the higher tier of NETGEAR Support, QoS on VOIP Traffic is an expedited forwarding, specific VOIP configuration. NETGEAR switch/es can prioritize this traffic using the DSCP traffic queue manager. When the higher tier of NETGEAR Support configured it, it was set to 5 – 6 level priority. Never had set it to 7 which had been a preferred rule and it seems to be fine.
The class_voip configuration is only necessary if the phone does not attach to the packet 101110 bit value. Then, you need to go in and manually setup a class for the QoS purpose. Now if the phone does add this bit value, then simple DSCP priority should already be EF as soon as DSCP is enabled. Following the guide here, it seems it needs to be updated for the new GUI as well as some of the configurations are seemingly incorrect and not correctly appropriated.
Regards,
DaneA
NETGEAR Community Team
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Re: QoS Prioritization for VoIP using DiffServ
Hi DaneA,
Thank you for your response - it is much appreciated.
Please see my attached screen-shots - this is how I have configured my switches to give the highest priority for our VoIP environment. We are using DSCP 46 (EF) for RTP and DSCP 26 (AF 31) for SIP. I have assigned queue number 2 to SIP and queue number 3 for RTP, but again, if you (or the higher Tier of Support as mentioned below) could take a look at the attached screen-shots, it would be greatly appreciated. I would just like to know if you think my configuration to give the appropriate priority for RTP and SIP (queue 3 & 2 respectively), is correct based on the attached screen-shots.
Thank you!
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I apologized for the late response. 😞 I forwarded your recent post to the higher tier of NETGEAR Support and just got a feedback today.
As per the higher tier of NETGEAR Support, based from the attachment, the configuration looks fine on AF31 and EF46 for DSCP.
Regards,
DaneA
NETGEAR Community Team
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Re: QoS Prioritization for VoIP using DiffServ
Okay great, thank you very much!