12-24-2015 07:27 AM - edited 03-05-2019 03:00 AM
Hi Everyone,
let me start by saying that I'm not very strong at all in qos stuffs, however unfortunately I need to replace an old C3750 with a C3850 IOS XE switch and I must translate the MLS Qos based configured on the 3750 in the MCQ Qos based on the 3850. The approach is very different and I wouldn't know how to proceed. The difference, if I'm not wrong, is that In MLS you assign buffers, thresholds and to each queues, in MCQ they are allocated per traffic classes. Then the difficulty is to obtain the traffic is treated the same way as in the old 3750.
This is the config. I omitted the input queue cause I read it is not supported in 3850.
mls qos srr-queue output cos-map queue 1 threshold 3 5
mls qos srr-queue output cos-map queue 2 threshold 3 3 6 7
mls qos srr-queue output cos-map queue 3 threshold 3 2 4
mls qos srr-queue output cos-map queue 4 threshold 2 1
mls qos srr-queue output cos-map queue 4 threshold 3 0
mls qos srr-queue output dscp-map queue 1 threshold 3 40 41 42 43 44 45 46 47
mls qos srr-queue output dscp-map queue 2 threshold 3 24 25 26 27 28 29 30 31
mls qos srr-queue output dscp-map queue 2 threshold 3 48 49 50 51 52 53 54 55
mls qos srr-queue output dscp-map queue 2 threshold 3 56 57 58 59 60 61 62 63
mls qos srr-queue output dscp-map queue 3 threshold 3 16 17 18 19 20 21 22 23
mls qos srr-queue output dscp-map queue 3 threshold 3 32 33 34 35 36 37 38 39
mls qos srr-queue output dscp-map queue 4 threshold 1 8
mls qos srr-queue output dscp-map queue 4 threshold 2 9 10 11 12 13 14 15
mls qos srr-queue output dscp-map queue 4 threshold 3 0 1 2 3 4 5 6 7
mls qos queue-set output 1 threshold 1 138 138 92 138
mls qos queue-set output 1 threshold 2 138 138 92 400
mls qos queue-set output 1 threshold 3 36 77 100 318
mls qos queue-set output 1 threshold 4 20 50 67 400
mls qos queue-set output 2 threshold 1 149 149 100 149
mls qos queue-set output 2 threshold 2 118 118 100 235
mls qos queue-set output 2 threshold 3 41 68 100 272
mls qos queue-set output 2 threshold 4 42 72 100 242
mls qos queue-set output 1 buffers 10 10 26 54
mls qos queue-set output 2 buffers 16 6 17 61
01-01-2016 10:44 PM
I think you are approaching this the wrong way. The systems are so different.
A better question is - what do you want the QoS policy to be?
Failing that, use the "macro apply" commands for Cisco recommend QoS settings based on the connection type.
E,g. For a connection to another switch:
interface Gigabit 0/0/1
macro apply cisco-switch
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