12-03-2020 02:02 AM
Hi all,
hope someone can help me and explain to me the following
I have an edge of the network with the following equipment, 1 Switch from Comnet, 1 Cisco 2960 and a Cisco 3650 where basically, the Comnet on vlan 40 (cameras) connects to the cisco 2960. The cisco 2960 as equipment on Vlan 20 and Vlan 40, on Vlan 20 I have recorders and on vlan 40 cameras. Then the 2960 connects with a trunk to the 3650 where all the traffic is routed.
Basically the traffic comes, enters the 2960, goes to the 3650 to be routed and then goes down again the same link to be recorded on the recorder on vlan 20, the traffic is going up and down.
My doubt is, if I put the cameras and the recorder on the same vlan without the need for the traffic to go up the fiber to be routed on the 3650, the ports of the 2960 don't give me any output drops, but if I put the traffic to be routed on the 3650 the uplink port of the 2960 to the 3650 is constantly giving me output drops and I can't understand why since I have a 1Gbps link and what's being used is 30 to 40% of the link, and is the uplink is not used and the traffic stays only in the 2960 not output drops are present on the ports that connect to the equipments.
To try to help the uplink port and after reading the cisco troubleshooting and the post from the community I implemented the following
On general config I put:
mls qos queue-set output 2 threshold 1 3100 3100 100 3200
mls qos queue-set output 2 threshold 2 3100 3100 100 3200
mls qos queue-set output 2 buffers 5 85 5 5
no mls qos rewrite ip dscp
mls qos
and on the port I put:
load-interval 30
srr-queue bandwidth share 5 85 5 5
queue-set 2
priority-queue out
Using the stats drops of port asis I saw the drops are happening in Queue 2, but after applying this it improved but still I continued with drops
Is this configuration correct or something else can be improved?
Thank you for the help
12-03-2020 02:59 AM
Helllo,
it is hard to tell if your QoS policy has any effect. What values is that based on ?
Either way, check if your switch supports the command:
qos queue-softmax-multiplier 1200
That usually should fix (most of) the output drops.
12-03-2020 02:55 PM
Thank you for the reply Georg. I used those values based on the troubleshooting from Cisco
That command isn't only for the Layer 3 switches? I think the 2960 doesn't have that command for the buffers but I'm going to check it out
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