I watched the extended webinar, and thank you so much. I was immediately able to take this knowledge and apply it in the real world. I had to build a QoS policy in windows with a decimal value of 26 for outgoing Cisco Jabber packets that were being reduced to CS0 and causing quality issues. I'm still in the process of resolving the issue overall, but having this solid understanding of DSCP has helped me make huge strides just today, and identify the issue and figure out how to correct it. Once again, Thanks, Kevin.
Great tutorial, I just finished my exam in QoS and got 76 points out of 80 points! But you can always learn something every day! Im not 100% sure I agree with you that AF23 is gonna be dropped before AF11. AF23 is still a higher major class than AF11. The minor class (drop pref) is the deciding factor in each specific major class. That means that AF23 should be dropped before AF22 and AF21 but not before AF11. AF23 being dropped before AF11 makes no sense at all. Did you make a mistake Kevin or am I skating on thin ice? I want to get some clarification on this.
Thanks for the quick response! Yeah but thats the whole point of WRED isnt it? So when you configure WRED you dont want the AF23 to be dropped before AF11 but before AF22 and AF21. I see it as an enhancement to instead of treating similar AF1 traffic the same (as IPP) you can use AF11, AF12 and AF13 for "less important" traffic in the same class. Lets say you configure HTTP as AF11, FTP as AF12 and telnet as AF23 and SSH as AF21. Example: HTTP and FTP both AF1 traffic. But you want HTTP to be slightly more important so you put it as AF11 and FTP as AF12. But you still want lets say telnet as AF23 to be more important than all of the AF1Xs but less important than SSH at AF21. Should congestion occur BETWEEN classes, the traffic in the higher class is given priority. If congestion occurs WITHIN a class the packets with the higher drop precedence are discarded first. The only time AF23 is getting dropped before AF11 is maybe if both of them are in the same class which by me is a weird configuration. Thanks for taking your time.
Yes I can agree that WRED does not concider the 3 left-most bits of the DSCP field and that it is the default. But Im just sayin that the whole point of having the drop bits is to differentiate the traffic WITHIN a class. You will never find a provider treating your AF3 the same as AF1 for example. So the default behaviour is kinda useless. Maybe you could just clarify next time that this would never happen in a live production network and give an example of how it might work in production networks. It might get confusing if you dont know how you use it in different classes and how you can tune it. Great video nonetheless. Thanks for clarifying. Good to talk to you, have a nice day.
Exactly! I agree with everything you just said. That was my whole point. I just think we are seeing it from different points of view. Im not disagreeing with you about how it works. I just want to clarify that usually traffic (example AF23) wont be in the same class as (example AF11) hence AF23 wont be dropped before AF11. But yeah, if they are in the same class it works exactly like you explained. English is my second language so I might not express myself exactly the way I want. No hard feelings ofc lol. You can always learn something new especially about QoS. Thank you, Im actually done with my studies now. I got my CCNP in Route, Switch and Tshoot.
Hi, Mr.Kevin. Your videos on CCNA and CCNP level are awesome.They way you present the information are much better than than any other instructors. Currently i am seeing your STP webinar. One thing that confuses me is "What is Network Segment?" This confuses me a lot because many other authors even do not use this term and their diagrams on STP is quite different. Kindly explain in detail so that no confusion remains. I know this is not the comment for this video but i want to ask. Thanks.
Let's say i want to use qos for gaming... should i use the value 46 as well?, since i don't really know what would be a specific dscp for gaming. Grea video by the way :)
Is there any advantage of using L2 marking compared to L3 marking? Or I guess the question should be is there any advantage of configuring QoS based on L2 rather than L3?
In that case, why would anybody choose to do their QoS configuration based on L2 marking. Why not use L3 marking right from the start even within a VLAN, and then you don't need to worry about remarking the L2, if the packet would leave a VLAN. Is there a case where L3 marking could not be used, and you would be forced to use L2 marking?
It is best practice to do QOS over layer 2 rather than layer 3. The reason for this being if you have every edge switch doing the marking, it distributes the load and allows you to delegate your resources more efficiently. If you were doing the marking via layer 3, that means you are more than likely having 1 or 2 routers doing the marking. Its a comparison of having lets say 20+ devices using their resources for marking, to 1 or 2 devices doing the marking and needing to use a lot of those layer 3 devices resources. Make sense? Its about spreading the load.
QOS is a very big study, always something new to discover everyday:)
I watched the extended webinar, and thank you so much. I was immediately able to take this knowledge and apply it in the real world. I had to build a QoS policy in windows with a decimal value of 26 for outgoing Cisco Jabber packets that were being reduced to CS0 and causing quality issues. I'm still in the process of resolving the issue overall, but having this solid understanding of DSCP has helped me make huge strides just today, and identify the issue and figure out how to correct it. Once again, Thanks, Kevin.
You're very welcome! I'm so glad you found the training helpful.
I have to say u are the best instructor on youtube that illustrated this topic , God bless u mr Kevin thank u very much
I don't usually hit the like button on TH-cam but this video was absolutely worth it.
Thanks very much, and I'm glad you enjoyed the training.
Brilliantly explained, thank you for showing the bit masks and explaining what each bit represents.
Very informative and explained very good and simple.. Thank you
This video finally made me understand markings! Thank you Kevin.. highly appreciate your time and efforts
VERY NICE Explanation !!! May God give you REWARD for this work done by you...
Big thanks! Wonderful explanation.
Thanks a lot, Kevin! This is the best explanation i have found, using 2 books and other videos online. Great video!
your tutorials are the best
Just amazing lecture can't thank you enough I was so confused about QOS
Excellent explanation! Thanks for the video!!
im having problem understanding the QOS marking with IPP and DSCP
But for 26 minutes of this VIds , answer the whole package of it. thanks
Great tutorial, I just finished my exam in QoS and got 76 points out of 80 points! But you can always learn something every day! Im not 100% sure I agree with you that AF23 is gonna be dropped before AF11. AF23 is still a higher major class than AF11. The minor class (drop pref) is the deciding factor in each specific major class. That means that AF23 should be dropped before AF22 and AF21 but not before AF11. AF23 being dropped before AF11 makes no sense at all. Did you make a mistake Kevin or am I skating on thin ice? I want to get some clarification on this.
Thanks for the quick response! Yeah but thats the whole point of WRED isnt it? So when you configure WRED you dont want the AF23 to be dropped before AF11 but before AF22 and AF21. I see it as an enhancement to instead of treating similar AF1 traffic the same (as IPP) you can use AF11, AF12 and AF13 for "less important" traffic in the same class. Lets say you configure HTTP as AF11, FTP as AF12 and telnet as AF23 and SSH as AF21. Example: HTTP and FTP both AF1 traffic. But you want HTTP to be slightly more important so you put it as AF11 and FTP as AF12. But you still want lets say telnet as AF23 to be more important than all of the AF1Xs but less important than SSH at AF21. Should congestion occur BETWEEN classes, the traffic in the higher class is given priority. If congestion occurs WITHIN a class the packets with the higher drop precedence are discarded first. The only time AF23 is getting dropped before AF11 is maybe if both of them are in the same class which by me is a weird configuration. Thanks for taking your time.
Yes I can agree that WRED does not concider the 3 left-most bits of the DSCP field and that it is the default. But Im just sayin that the whole point of having the drop bits is to differentiate the traffic WITHIN a class. You will never find a provider treating your AF3 the same as AF1 for example. So the default behaviour is kinda useless. Maybe you could just clarify next time that this would never happen in a live production network and give an example of how it might work in production networks. It might get confusing if you dont know how you use it in different classes and how you can tune it. Great video nonetheless. Thanks for clarifying. Good to talk to you, have a nice day.
Exactly! I agree with everything you just said. That was my whole point. I just think we are seeing it from different points of view. Im not disagreeing with you about how it works. I just want to clarify that usually traffic (example AF23) wont be in the same class as (example AF11) hence AF23 wont be dropped before AF11. But yeah, if they are in the same class it works exactly like you explained. English is my second language so I might not express myself exactly the way I want. No hard feelings ofc lol. You can always learn something new especially about QoS. Thank you, Im actually done with my studies now. I got my CCNP in Route, Switch and Tshoot.
Hi, Mr.Kevin. Your videos on CCNA and CCNP level are awesome.They way you present the information are much better than than any other instructors. Currently i am seeing your STP webinar. One thing that confuses me is "What is Network Segment?" This confuses me a lot because many other authors even do not use this term and their diagrams on STP is quite different. Kindly explain in detail so that no confusion remains.
I know this is not the comment for this video but i want to ask.
Thanks.
Can we say network segment is that which has one collision domain?
Just an excelent video! Thank you.
truly amazing, thank you for your explanation.
It's really well explanied
Multimedia would go in a LLQ or CBWFQ queue?
Ty for this video
Thank you so much for the awesome explanation!!!!!!!!!!!!!!
Hello dear it is very good explanation but I need to practice with CCNA V-3 qeustion too which one the most trusted sample of the exam
great content, very helpful
you sir are fantastic!!! thank you!
It is wonderful!
Thank you!
I did subscribe to your channel!
I have one question is CS packets are not dropped under any conditions ? as they have 0 probability of drop ??
Let's say i want to use qos for gaming... should i use the value 46 as well?, since i don't really know what would be a specific dscp for gaming. Grea video by the way :)
Is there any advantage of using L2 marking compared to L3 marking? Or I guess the question should be is there any advantage of configuring QoS based on L2 rather than L3?
In that case, why would anybody choose to do their QoS configuration based on L2 marking. Why not use L3 marking right from the start even within a VLAN, and then you don't need to worry about remarking the L2, if the packet would leave a VLAN.
Is there a case where L3 marking could not be used, and you would be forced to use L2 marking?
It is best practice to do QOS over layer 2 rather than layer 3. The reason for this being if you have every edge switch doing the marking, it distributes the load and allows you to delegate your resources more efficiently. If you were doing the marking via layer 3, that means you are more than likely having 1 or 2 routers doing the marking. Its a comparison of having lets say 20+ devices using their resources for marking, to 1 or 2 devices doing the marking and needing to use a lot of those layer 3 devices resources. Make sense? Its about spreading the load.
Where to set this DSCP value in windows server or in Linux server? And how to set?
Dear kevin, what goes first marking or classification ?
We typically classify first, then mark.
E X C E L L E N T !
Thanks very much! I'm glad you enjoyed the video.
Hello dear I am preparing to take CCNA version 3 exam and would you send me your link to buy and also I am looking the most trusted sample exam thanks
Has dearest done the needful?
What is a default dscp value for voice traffic? Is it 46?
Thanks..
Can anyone explain at 18:27 .How af40 becomes 101000 it should be 100000 right?
@@kwallaceccie thank you so much kevin
if AF41 is 100010, why is AF40 101000 ? shouldn't it be 100000 ?
AF40 isn't a valid DSCP value.
thank you so much for explanation, please can you be slower for students with not native English language
Thanks for your interest mr Kevin , i tried but i don't feel comfortable with this feature