01-04-2020 08:46 AM
Hello,
I use 3750X switches with IOS version 152-4.E9.
I'm looking to prioritize all traffic for VLANs 10 to 30 (data enterprise), the other VLANs will be in best effort.
Is it possible to prioritize traffic for some VLAN ?
Thank you in advance for your help.
01-04-2020 09:49 AM
Instead of VLAN, you can do per Subnet IP based QoS Policy.
reference guide :
01-04-2020 10:48 AM
01-04-2020 12:18 PM
Is it possible to have a policy-map with VLANs?
Should we do QoS on traffic only or should we specify a bandwidth?
VLAN 10 which will have priority over traffic for example from VLAN 8. The two VLANs are connected to 100M.
Which method to use?
01-04-2020 04:50 PM
Below are restrictions applied when you do QOS based on VLAN Tags.:
"The router does not support the random-detect and priority commands for traffic classes created using the match-vlan command in class maps"
Ref: https://www.cisco.com/c/en/us/td/docs/ios/12_2sb/feature/guide/vlntgqos.html
The best option for you would be matching subnet which will support "Priority" configuration for the traffic classified by class_maps.
01-04-2020 08:39 PM
I recommend to use an access-list with subnet associated with VLAN and create QoS Policy based on that to mark as per the requirement.
01-05-2020 01:59 AM
OK I will use an access-list with subnet, I will not use VLANs !
If I understand it is necessary to make two configurations, one on the switch and the other on the router ?
It is not possible to do QoS only on the switch in order to prioritize subnet ?
01-05-2020 06:03 AM
Usually there is no need to apply it on the LAN witches due to high speed links available already.
We need to apply QOS on slower links which are WAN links in most of the cases that are terminating on the Routers.
So, apply it on the Edge Router which is terminating WAN connections.
01-05-2020 08:09 AM - edited 01-05-2020 08:19 AM
"Should we do QoS on traffic only or should we specify a bandwidth?"
Sorry, I don't understand the question.
As noted in my earlier reply, yes you can prioritize one VLAN's traffic over another on a 3750-X. How, though, depends on your topology.
"Which method to use?"
Again, your question, to me, is unclear. Which methods did you want to have an opinion on?
[edit - PS:}
BTW, the configuration guide for a 3750-X, 15.2(4)E is: https://www.cisco.com/c/en/us/td/docs/switches/lan/catalyst3750x_3560x/software/release/15-2_4_e/configurationguide/b_1524e_consolidated_3750x_3560x_cg/b_1524e_consolidated_3750x_3560x_cg_chapter_0101110.html
This is a bit more germane to your question on 3750-X QoS then the other posters' references.
You might want to start with the section on "Restrictions for QoS".
01-05-2020 09:49 AM
Here is the network diagram :
For example on switch 5 the uplink is only 100M, I want to prioritize VLANs 10 and 20 (subnet 192.168.10.X & 192.168.20.X) if for example VLANs 7 and 8 are too consuming.
The speed must always have priority for SUBNET 192.168.10.X to 192.168.30.X, the others will not have priority ...
Do you understand what I am trying to do?
01-05-2020 01:33 PM
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