The AP/SM are not setting DSCP, they are reacting to it. A lot of VoIP equipment defaults to DSCP=46.
From: Af [mailto:[email protected]] On Behalf Of Chuck McCown Sent: Thursday, January 12, 2017 1:13 PM To: [email protected] Subject: Re: [AFMUG] Cambium 450 QOS for Voip I would always turn VoIP up to 11 on the dial. I doubt 46 vs 56 is really going to do much, but I would rather have Voip quality take priority over network control if there ever became a conflict. Odd, I thought Flash Override was the highest. From: Sam Kirsch Sent: Thursday, January 12, 2017 12:10 PM To: [email protected] Subject: Re: [AFMUG] Cambium 450 QOS for Voip I've also always wondered what the strongest VoIP QoS settings were on the Cambium equipment. I've been setting Codepoint 46 to 5 on the APs and SMs and setting Diffserv first as well in some areas where we can have lots of VoIP issues (old PMP100 900mhz APs, for example). According to all the documentation I can find that's the correct/most standardized way of setting this for VoIP in a WAN environment, but I always thought it was odd that Cambium stuff came defaulted with half of the items set to 0 and the other to 4 and 802.1p > DiffServ, instead of following the recommended Cisco chart and various advice one can find on the internet; DSCP Name DS Field Value (Dec) IP Precedence (Description) CS0 0 0 : Best Effort CS1,AF11-13 8,10,12,14 1 :Priority CS2,AF21-23 16,18,20,22 2 :Immediate CS3,AF31-33 24,26,28,30 3 :Flash - mainly used for voice signaling CS4,AF41-43 32,34,36,38 4 :Flash Override CS5,EF 40,46 5 :Critical - mainly used for voice RTP CS6 48 6 :Internetwork Control CS7 56 7 :Network Control I always assume that the more I'm changing the more likely I am doing something wrong =D I'd like some clarification on this as well! Regards, -- Samuel Kirsch, Network Support Plexicomm - Internet Solutions | <http://www.plexicomm.net/> www.plexicomm.net Office: 1.866.759.4678 x109 | Fax: 1.866.852.4688 Emergency Support: 1.866.759.9713 | [email protected] ------ Original Message ------ From: "Andreas Wiatowski" <[email protected]> To: "[email protected]" <[email protected]> Sent: 1/12/2017 11:46:40 AM Subject: Re: [AFMUG] Cambium 450 QOS for Voip Yes…this is what we do… my concern has been “TELLING THE AP” that this traffic has precedence over any other types of traffic “JUST IN CASE” the AP is taxed in terms of available airtime / bandwidth. So based on this I would have to set the Codepoint 46 to priority 7 on the AP Diffserve TAB SM turn on High priority then set the SM DIFFSERV Tab Codepoint 46 to priority 7 and set DIFFSERV first over 802.1p Cheers, ______________________________ Andreas Wiatowski | CEO Silo Wireless Inc. Email [email protected] 19 Sage Court Brantford, Ontario N3R 7T4 (CANADA) Tel +1.519.449.5656 Extension-600|Fax +1.519.449.5536 |Toll Free +1.866.727.4138 From: Af [mailto:[email protected]] On Behalf Of Ken Hohhof Sent: Thursday, January 12, 2017 11:38 AM To: [email protected] Subject: Re: [AFMUG] Cambium 450 QOS for Voip Then I assume the PBX is already setting DSCP on the traffic to the customer, and if they have ATAs or IP phones, those probably also set DSCP. I would not set all traffic from this customer to high priority in the QoS router, just the VoIP traffic. From: Af [mailto:[email protected]] On Behalf Of Andreas Wiatowski Sent: Thursday, January 12, 2017 10:34 AM To: [email protected] Subject: Re: [AFMUG] Cambium 450 QOS for Voip We run our own PBX server and bring trunks to it. The traffic flow comes via our PBX… It is on our network and not outsourced. Thanks for the info. Cheers, ______________________________ Andreas Wiatowski | CEO Silo Wireless Inc. Email [email protected] 19 Sage Court Brantford, Ontario N3R 7T4 (CANADA) Tel +1.519.449.5656 Extension-600|Fax +1.519.449.5536 |Toll Free +1.866.727.4138 From: Af [mailto:[email protected]] On Behalf Of Ken Hohhof Sent: Thursday, January 12, 2017 11:27 AM To: [email protected] Subject: Re: [AFMUG] Cambium 450 QOS for Voip Yes, you should enable High Priority channel and assign an appropriate amount of bandwidth, e.g. 100 kbps times number of simultaneous calls, depending on what codec their VoIP is using. This allocation is only used if needed, it’s not like some QoS routers which set aside bandwidth only for use by high priority traffic. Most VoIP devices should tag the packets as EF without needing a QoS router to do it. Where you tag the downstream traffic depends on where it is coming from. Do you have your own PBX? Does it come over a SIP trunk? Does the RTP traffic flow via your PBX or come direct from the underlying CLEC? I think this depends on whether you enable re-invites? From: Af [mailto:[email protected]] On Behalf Of Andreas Wiatowski Sent: Thursday, January 12, 2017 10:13 AM To: [email protected] Subject: [AFMUG] Cambium 450 QOS for Voip Hi All, We have been running VOIP very successfully for quite some time to business customers. Typically we put in a QOS router at the premise and mark DSCP and prioritize. My question is, as we fill up AP’s we sometimes get comments from customers that their VOIP sometimes cuts out..or is choppy….not all the time…just the odd time. Should we be enabling the “HIGH PRIORITY” channel in the SM interface? If so, Anything to do at the AP? Does this prioritize DSCP? Cheers, ______________________________ Andreas Wiatowski | CEO Silo Wireless Inc. Email [email protected] 19 Sage Court Brantford, Ontario N3R 7T4 (CANADA) Tel +1.519.449.5656 Extension-600|Fax +1.519.449.5536 |Toll Free +1.866.727.4138
