QoS on Layer 2 and Layer 3

[TheDukeofBaghdad]

Hi Friends,

I hate the fact that I have weak memory and keep forgetting important information as I have read QoS multiple times but since I don't work with it a lot I keep forgetting it :(

Anyway,

I have a Network Consist of Cisco Layer 2 Industrial switches "IE-3010" and the Backbone is Cisco Layer 3 Catalyst Switches "4507".

I am using a different VLANs for Each system (ex. CCTV, VOIP, DATA .. etc) and the VLANs passes thourgh the layer 2 switches and end at the Backbone Switch as it have Layer 3 links to the other Backbone switches.

What is the easiest QoS I can apply to give VOIP traffic priority above the Uplink between the Layer 2 switch to the Layer 3 Switch (Trunk link 802.1q) and between the Backbone switches (Layer 3 link)

Thanks Friends for your help.

Best Regards,

[Georg Pauwen]

Hello,

what are your VoIP devices, are these Cisco phones ?

[Dean Romanelli]

Hi,

It depends.  Are your phones already configured with QoS markings, or will you need to assign markings to the VOIP traffic?  Are the phones plugged directly into the layer 2 switches you speak of?  Are the layer 2 switches and the 4507 switch physically in the same footprint/location? Are you using or do you want to use CoS or DSCP markings?

[TheDukeofBaghdad]

Georg Pauwen, Dean Romanelli,

The phones are 3rd vendor (not-Cisco) but it does mark the traffic with Diffserv 46.

The phones are plug directly to the layer 2 switches.

The Layer 2 and the Layer 3 switches are not in the same physical location.

Since we have Layer 2 and Layer 3 links I think the DSCP is more suitable but will the Cisco IE-3010 be able to read it and use it to prioritize VOICE traffice?

[Georg Pauwen]

Hello,

the IE 3010 supports automatic quality of service (QoS) Voice over IP (VoIP) enhancement for port-based trust of DSCP. You can use 'auto qos voip trust' on the uplink ports to trust the VoIP classification that comes from the phones (page 33-25 of the attached user guide).

As such, the IE 3010 works just like any other switch that supports mls qos...

https://www.cisco.com/c/en/us/td/docs/switches/lan/cisco_ie3010/software/release/12-2_53_ez/configuration/guide/ie3010scg.pdf

[TheDukeofBaghdad]

Hi Georg,

Thanks for your respond.

I did found the mls qos and the auto qos yesterday and play with it a little bit but didn't want to add something I don't understand what's going on in the back! and weather I should enable it to the ports that going to the phones or the Trunk links (The UPLINK) or both?

I am reading the document right now.

Thanks again

[Bob Loblaw]

L2 Switch:

Trust commands on the interfaces the phones are connected to.

L3 Switch:

Trust command on the trunk to L2

This allows dscp tags from the phones to go through the l2 switch and the l3 switch will trust dscps coming in through the trunk.

If you want to also prioritize incoming calls from the outside you will need some extra steps to mark the traffic. I'm not familiar with those particular pieces of equipment, so I can't give specifics.

Hope this helps.

[TheDukeofBaghdad]

hi michael.trujillo,

So the Backbone switch is Cisco 4507 which doesn't support mls qos but it support:

qos trust extend

will this command do the trick ?

Thanks,

[TheDukeofBaghdad]

Good Morning Georg,

The Auto-QoS generate the following configuration, is this enough for this switch:

+mls qos map cos-dscp 0 8 16 24 32 46 48 56
+mls qos srr-queue input bandwidth 90 10
+mls qos srr-queue input threshold 1 8 16
+mls qos srr-queue input threshold 2 34 66
+mls qos srr-queue input buffers 67 33
+mls qos srr-queue input cos-map queue 1 threshold 2 1
+mls qos srr-queue input cos-map queue 1 threshold 3 0
+mls qos srr-queue input cos-map queue 2 threshold 1 2
+mls qos srr-queue input cos-map queue 2 threshold 2 4 6 7
+mls qos srr-queue input cos-map queue 2 threshold 3 3 5
+mls qos srr-queue input dscp-map queue 1 threshold 2 9 10 11 12 13 14 15
+mls qos srr-queue input dscp-map queue 1 threshold 3 0 1 2 3 4 5 6 7
+mls qos srr-queue input dscp-map queue 1 threshold 3 32
+mls qos srr-queue input dscp-map queue 2 threshold 1 16 17 18 19 20 21 22 23
+mls qos srr-queue input dscp-map queue 2 threshold 2 33 34 35 36 37 38 39 48
+mls qos srr-queue input dscp-map queue 2 threshold 2 49 50 51 52 53 54 55 56
+mls qos srr-queue input dscp-map queue 2 threshold 2 57 58 59 60 61 62 63
+mls qos srr-queue input dscp-map queue 2 threshold 3 24 25 26 27 28 29 30 31
+mls qos srr-queue input dscp-map queue 2 threshold 3 40 41 42 43 44 45 46 47
+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
+mls qos
interface FastEthernet0/18
+srr-queue bandwidth share 10 10 60 20
+priority-queue out
+mls qos trust cos
+auto qos voip trust
interface FastEthernet0/19
+srr-queue bandwidth share 10 10 60 20
+priority-queue out
+mls qos trust cos
+auto qos voip trust
interface GigabitEthernet0/1
+srr-queue bandwidth share 10 10 60 20
+priority-queue out
+mls qos trust cos
interface GigabitEthernet0/2
+srr-queue bandwidth share 10 10 60 20
+priority-queue out
+mls qos trust cos

[Georg Pauwen]

Hello,

since your voice traffic is using the standard marking (DSCP 46/EF) the auto qos should be sufficient.