Quality of Service (QoS) Explained

[Alidashti2010]

Thank you

[GreedeeVids]

Thanks for taking the time to explain this to me my friend. Mike your a great teacher. You explained this very well and I got it first try :)

[tias88]

Big thanks to you for this video, i am a beginner in Networking, haven't done that much more then installing some simple auto-configurating devices, i have although just recieved my first Fiber Switch (48 ports) and a 1U router aswell, and i desperately need to set up QoS on this rig, so thanks for explaining it in a straight and easy way

[INquantico]

excellent explanation. I read a 40 slides presentation and got allot less then this. Thank you.

[RaulCasillas08]

Hey Mike , May i ask you what is the difference between COS & QOS ? Is COS part of QOS but for Layer 2 i.e. is COS = QOS for L2 ( on switches ) ?

Thanks prof.

[RaulCasillas08]

QOS are three things if am not wrong

Classifiying , Marking & Policing

[TheYouSphere]

You're great at explaining things, just one suggestion. Take a few introductory to cartooning courses, your diagrams will definintely become nicer as a result, and you'll have fun along the way.

[windsorize]

nice explanation. thanks for that.

[mlbinftl]

@michaeljcavanaugh I like how simple you made this. Do you have one on SNMP? thanks for this video

[michaeljcavanaugh]

@mlbinftl I do not have one on SNMP, but will add that to my list. Look for it in the future. Thanks!

[johnhtafc]

Thank you for this video!

[ybgururaj]

Hi Mike amazing video its so simple and crisp even a layman to networks can understand. Great work keep them coming.

[raymondjparadise]

Thank you for this info - very helpful.

[Fedesiete]

Great explanation! thank you very much!

[TubeNaany]

Hi Mike.. wonderful explanation .. Thanks!!

[diablorave1]

Ok this sounds great I have a question tho lets say im connected via ethernet cable to my router and there's a wireless computer connected to the router wireless and that computer is downloading, this tends to slow down my device, would (qos) ethernet port priority change that problem?

[michaeljcavanaugh]

@diablorave1 You are saying that your wired device slows down when the wireless computer downloads a large file? I assume that the router is both the wired and wireless provider and the file is coming to the WAN port of your router. If this is accurate, port priority would not help you because all traffic is coming in one interface. You need to traffic shape and prioritize the traffic being handed to your router at the next hop router as you have little control over what is being handed to you.

[morresi2011]

That was a great explanation! thanks! regards from Argentina

[delabuen]

Hi Mike. Just a quick question. If the router does not offer QoS service but has traffic shaping set up, do you think by setting up the QoS on the switch, it would make my voice packets move more freely? Thanks

[michaeljcavanaugh]

@delabuen If you set up QoS on the switch, voice will take priority on the switch, but will run into issues on the router if the router is congested. QoS is a hop by hop configuration, meaning every device must participate for end to end QoS to occur.

[shnoweez333]

good job, well explained...more network vids please

[Factuss]

Hi Mike, you basic presentation of QoS was very valuable and clear.

[SumAznKid215]

hi michael, thankyou for this lesson, this really helped me understand this subject, i have a oral presentation ased on challenges of the internet and one topic was QoS, this really help at the last second

[thelostpackets]

Great explanation but I have several questions. Right now our pseudo voip is an archaic NEC Aspire system and our office router is a Cisco 2801. So data traffic is 192.168.1.0/24 and voice traffic is 192.168.2.0. I have a bonded 3MB pipe that connects two offices, say Atlanta and Miami, using ppp Multilink. Can I setup QoS on the 2801 based on subnet instead of packet type? So priotize 192.168.2.0/24 first? Thanks for any input.

[TheADDActress]

@thelostpackets Yes, actually, you can. To match a subnet use an access list to match all traffic to and from 192.168.2.0 /24. Then place that traffic in the priority queue.

Thanks,

Caitlin

(Michael's Daughter [with dad looking over my shoulder ;D])

[michaeljcavanaugh]

@thelostpackets Yes, you can match traffic based on subnet vs DSCP mark and place that traffic in the priority queue.

[ramanan86]

thank you very much for this very clear explanation :)

[chieftanzzz]

Thanks for the info..So if you have a switch or router that does not support QOS does this mean its the weakest link in the network and slow down the whole path?

[michaeljcavanaugh]

@chieftanzzz Yes.. That is exactly what can happen. Remember that QoS only works when you have congestion... if there is no contention for transmission then you do not need QoS. A soon as there is more traffic to transmit than the current bandwidth will allow, some packets will have to wait in queue or get dropped. If you do not have QoS on one hop along the path, that hop can delay or drop voice traffic even though the rest of your network has QoS capabilities.

[1000HPCLUB]

Very clear and simple to understand explanation, thank you very much.