# How to configure Queuing on Cisco 3560 and 3750 switch
**URL:** https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863
**Category:** Lessons Discussion
**Created:** [December 20, 2016, 9:57pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863 "2016-12-20T21:57:50Z")
**Posts on this page:** 20
**Page:** 1
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [December 20, 2016, 9:57pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/1 "2016-12-20T21:57:50Z")
This topic is to discuss the following lesson:
> **[Queuing on Cisco 3560 and 3750 switch](https://networklessons.com/quality-of-service/how-to-configure-queuing-on-cisco-catalyst-3560-and-3750-switch)**
>
> This lesson teaches you queueing operates and the configuration of Cisco Catalyst 2960, 3560, and 3750 switches.
---
### Author:  [@system](https://forum.networklessons.com/u/system)
#### Post date: [May 24, 2013, 3:56pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/2 "2013-05-24T15:56:48Z")
Hi,
Very good post.
I just wonder if the bandwith concerned by weigthing ingress trafic is really the interface bandwidth or the internal ring ( or stack ring) bandwidth.
“The command makes queue 1 the priority queue and limits it to 20% of the bandwidth of the interface.” =\> I think it is of the internal ring bandwidth
(see [http://www.cisco.com/en/US/products/hw/switches/ps5023/products\_tech\_note09186a0080883f9e.shtml](http://www.cisco.com/en/US/products/hw/switches/ps5023/products_tech_note09186a0080883f9e.shtml))
best regards
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [June 6, 2013, 1:07pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/3 "2013-06-06T13:07:00Z")
Hi Jean-Marc,
I just checked it and you are right, it’s the stack ring bandwidth. I just changed it in the lesson…thanks for pointing it out!
Rene
---
### Author:  [@system](https://forum.networklessons.com/u/system)
#### Post date: [October 20, 2013, 8:35am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/4 "2013-10-20T08:35:57Z")
Hi,
Just one note: Egress queueing is defaulted to Q1 being the priority queue and has 1/25 \* 100Mb (4Mb) so your first calculation didn’t cover this already assigned usage. Your teaching method works well though but it’s nice to know.
Thanks.
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [October 23, 2013, 8:51am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/5 "2013-10-23T08:51:36Z")
Thanks Alan, that’s something to keep in mind indeed.
---
### Author:  [@system](https://forum.networklessons.com/u/system)
#### Post date: [April 18, 2014, 2:54am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/6 "2014-04-18T02:54:11Z")
Hi Rene,
Thank you for the information. It was very helpful. However do you have any postings on QoS for the new 3850’s? I will be replacing our 3750x stack switches soon with a couple of 3850’s and noticed the QoS model is different. It now uses MQC instead of MLS, 8 queues instead of 4, etc. and so I was wondering if you can help answer some questions.
First, do I have to use/configure all 8 queues or can I just configure queues similar to the four that we originally have on our 3750’s?
We have a few layer two switches that will be connecting to the stack. I’m assuming it shouldn’t matter if they are using the old method of queueing, as long as they are marked and classified correctly, the stack switches will handle the queueing once it receives it?
Also if I have a port that could be used for a cisco phone or a just a pc, should I still use the" trust device cisco-phone" on the port or leave it default (trust all)?
Thanks,
Mary
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [May 1, 2014, 1:30pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/7 "2014-05-01T13:30:16Z")
Hi Mary,
I haven’t played with QoS on the 3850 yet, once I get my hands on one I’ll write a blog post on it. Configuration-wise it should be much easier since it’s all MQC now.
You probably don’t have to use all 8 queues so if you just want 4 you should be fine but make sure to check the buffer allocations for all the different queues. It doesn’t matter that you still have your old switches as long as the marking is the same. Your 3850s will queue just fine if the markings are OK.
You can leave the trust level at the default (trust all) as long as you trust the markings from all your end devices. Make sure you don’t have any computers or other devices that mark their traffic when they shouldn’t…otherwise it’s better to rewrite everything to 0 and just trust the (Cisco) phones.
I’ll see if I can get my hands on a 3850 so I can write some blog posts about it 🙂
Rene
---
### Author:  [@joe1664](https://forum.networklessons.com/u/joe1664)
#### Post date: [December 21, 2015, 11:25pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/8 "2015-12-21T23:25:37Z")
Rene,
Is there any course material that explains QOS WRR? I’m trying to figure why I dont see any global configuration lines on my 6509, however, when I run Show queueing interface gi 9/1 (for example), I see WRR wred settings, also, I see Output Discards on Queue 0 discarding cos 0 & 1 data. MLS Qos is enabled.
Any thoughts?
Thanks!
Joey
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [December 28, 2015, 5:14pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/9 "2015-12-28T17:14:44Z")
Hi Joey,
Configuration-wise, WRR (Weighted Round Robin) and SRR (Shaped Round Robin) are very similar. You can use the examples in this lesson:
> **[Queuing on Cisco 3560 and 3750 switch](https://networklessons.com/quality-of-service/how-to-configure-queuing-on-cisco-catalyst-3560-and-3750-switch)**
>
> This lesson teaches you queueing operates and the configuration of Cisco Catalyst 2960, 3560, and 3750 switches.
Something to keep in mind is that a lot of commands will only show up in your configuration if you use non-default values. Here’s an example:
```auto
Switch#show running-config | incl mls
mls qos
```
QoS has been enabled on this switch, that’s the only command we have in our config. Let’s check the default cos-dscp map:
```auto
Switch#show mls qos maps cos-dscp
Cos-dscp map:
cos: 0 1 2 3 4 5 6 7
--------------------------------
dscp: 0 8 16 24 32 40 48 56
```
If you try to add this to your config, it won’t show up. Here’s an experiment:
`Switch(config)#mls qos map cos-dscp 0 8 16 24 32 40 48 56`
```auto
Switch(config)#do sh run | incl qos
mls qos
```
It doesn’t show up since these are the default values. Only if we change something it will show up:
```auto
Switch(config)#mls qos map cos-dscp 0 8 16 24 32 40 48 60
Switch(config)#do sh run | incl qos
mls qos map cos-dscp 0 8 16 24 32 40 48 60
mls qos
```
Now you can see it in the config. There is another way though…if you use **show running-config all** then you will see everything, including the defaults:
```auto
Switch#show running-config all | incl mls
mls qos rewrite ip dscp
mls qos
mls qos cos 0
mls qos dscp-mutation Default DSCP Mutation Map
```
The **mls qos cos 0** and **mls qos dscp-mutation Default DSCP Mutation Map** are found on the interfaces.
Rene
---
### Author:  [@shuarma](https://forum.networklessons.com/u/shuarma)
#### Post date: [January 8, 2016, 11:11pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/10 "2016-01-08T23:11:56Z")
Hi rene.
Do you have an lesson or document where you explain better, I have many doubts?
Thanks.
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [January 11, 2016, 11:48am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/11 "2016-01-11T11:48:17Z")
Hi Edgar,
About queuing? What doubts do you still have, maybe I can clarify them? 🙂
Rene
---
### Author:  [@shuarma](https://forum.networklessons.com/u/shuarma)
#### Post date: [January 12, 2016, 12:06am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/12 "2016-01-12T00:06:02Z")
Hello Rene
yes, all my douts are about queuing. I don’t understand it.
sorry ☹
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [January 12, 2016, 3:54pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/13 "2016-01-12T15:54:27Z")
Hi Edgar,
Queuing on switches can be complicated to understand. Did you see this video yet?
[ ](https://www.youtube.com/watch?v=6UJZBeK_JCs)
It’s a great video, explains the basics of queuing on the catalyst switches.
Rene
---
### Author:  [@agatyinta](https://forum.networklessons.com/u/agatyinta)
#### Post date: [April 28, 2016, 1:37pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/14 "2016-04-28T13:37:28Z")
Hi Rene,
Great post as usual with all your postings. Im wondering if you can put together a comprehensive example as how to use all these commands in a real world scenario. This way we understand the reason or the need behind each one of them. Also I would like to see an end to end QoS implementation in an easy way to understand as you did in all your postings.
Ahmad
---
### Author:  [@ReneMolenaar](https://forum.networklessons.com/u/ReneMolenaar)
#### Post date: [May 2, 2016, 4:27pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/15 "2016-05-02T16:27:00Z")
Hi Ahmad,
Glad to hear you like it. I might add some of these examples when I’m working on design material.
When it comes to QoS, here’s what you should do:
- On the edge of your network, you want your traffic to be marked. If you use VoIP, your IP phones are probably already doing this for you. You can also use classification on the switch and mark the traffic there.
- If you want to queue traffic then you should configure queuing on any device in between the source and destination. Make sure you do this in both directions.
Rene
---
### Author:  [@agatyinta](https://forum.networklessons.com/u/agatyinta)
#### Post date: [May 2, 2016, 7:09pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/16 "2016-05-02T19:09:01Z")
Solid info. Great!
---
### Author:  [@mahamanebana](https://forum.networklessons.com/u/mahamanebana)
#### Post date: [May 12, 2016, 2:11am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/17 "2016-05-12T02:11:19Z")
What’s the difference between priority queue and priority queuing. In this article, you stated that we have two(2) ingress queues. I was reading an online document where I found that there are 4 queues of traffic in Priority Queuing. Can you help me understand this? I’m sending you the link and please read the section where it said Priority Queuing
[http://netcerts.net/congestion-management-and-queuing-methods/](http://netcerts.net/congestion-management-and-queuing-methods/)
---
### Author:  [@andrew](https://forum.networklessons.com/u/andrew)
#### Post date: [May 13, 2016, 2:58pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/18 "2016-05-13T14:58:08Z")
Hi Mahamane,
This can be confusing because the terms are so similar, but they are quite different. One is describing a **method** of ordering packets, while the other describes a queue itself–in other words a logical construction where packets are held.
Priority Queuing
This is describing a method of ordering packets. Note: This is an older generation method that is considered legacy now. The way this works is there are four queues (in order of importance): High, Medium, Normal, Low. Priority Queuing works with a simple rule: A queue will only be serviced so long as there are no packets waiting in a higher importance queue. In other words, any packets in the “Normal” queue must continue to wait to be sent until all the packets in High, then Medium are already sent.
Priority Queue
This describes a queue itself, rather than a method of queuing. The concept for a priority queue is pretty simple. Any packet that enters the Priority Queue is immediately placed at the front of the line so it will be sent next. This is commonly used for VOIP traffic where low delay is critical for functionality.
---
### Author:  [@francisini01](https://forum.networklessons.com/u/francisini01)
#### Post date: [May 27, 2016, 11:37am UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/19 "2016-05-27T11:37:54Z")
Hi Rene,
Any idea how the QoS works for 3850 Switch model?. as far as i know. MLS QoS only works with 3750 and 3850 dont have this command.
Thanks,
Francis
---
### Author:  [@andrew](https://forum.networklessons.com/u/andrew)
#### Post date: [May 27, 2016, 2:01pm UTC](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863/20 "2016-05-27T14:01:25Z")
Francis,
You are right, the 3850 doesn’t support the MLS mode of QoS, and that’s a good thing! MLS is now considered legacy and has been superseded by MQC (modular QoS CLI). The MQC is more universal in nature–meaning its configuration is the same across a variety of platforms. It also has a lot more capabilities than MLS (for example, multiple nested QoS policies).
Here’s a link to Cisco that highlights the differences:
[http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3850-series-switches/118629-technote-qos-00.html#anc4](http://www.cisco.com/c/en/us/support/docs/switches/catalyst-3850-series-switches/118629-technote-qos-00.html#anc4)
[Next page](https://forum.networklessons.com/t/how-to-configure-queuing-on-cisco-3560-and-3750-switch/863.md?page=2)