Network traffic priority best practices at switch level

Looking at the commands you have implemented, i think what you are missing is the match criteria.

Config:

policy-map {policy name} in

class {class name}

match vlan 2

assign-queue 6

exit

interface port-channel 1

service-policy in {policy name}

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The match criteria was configured, but it has to be configured somewhat different than you have explained.

This is also part of my configuration:
class-map match-all WGF ipv4 match vlan 30 exit

I think the assign queue command isn't appropriate for giving some traffic a higher priority over standard traffic. I was looking for someone to confirm of denial my thoughts of how to prioritize network traffic...

If I take a look in switch queuing in a general way, I would need to give my high priority network traffic a ToS byte value of '1000' to minimize delay. But now I have to configure it with DIFFSERV, I don't really understand what I am doing. I think I'll to use DSCP values instead of the queue command.

Do you agree?

Here's my source: http://www.cisco.com/en/US/technologies/tk543/tk766/technologies_white_paper09186a00800a3e2f_ps6610_Products_White_Paper.html

Maybe I've to configure 'mark ip-dscp ??' instead of 'assign-queue 6'? My next question will be: what dscp value I'll need to minimize delay, maximize reliability with a normal bandwidth? I've got this source which should make things clear, but I don't know how to read the table: http://bogpeople.com/networking/dscp.shtml. There are 6 binary values in the table, and the RFC791/RFC1349 is giving me 8 values...

Assigning queue 6 is perfectly fine and usually done when handling voice traffic. It may help to know what traffic you are wanting to give extra priority to. The priority goes from 0-6,lowest-highest priority.

This document is about VOIP, but it also goes into QoS. The commands wont be the same, but the general info is good.

http://www.dell.com/downloads/global/products/pwcnt/en/app_note_11.pdf

When it comes to priority each network can have different needs and goals. Because of this I don’t have a chart or list that shows which CoS we recommend placing certain traffic. I found an example chart on Cisco's site of priority levels that could be given out. But again these could change for each network you run into.

http://www.cisco.com/en/US/docs/solutions/Enterprise/Data_Center/VMDC/2.2/collateral/IPVS_files/IPVS-12.jpg

Wikipedia also has a similar example chart.

"The way traffic is treated when assigned to any particular class is undefined and left to the implementation. The IEEE however has made some broad recommendations:"

http://en.wikipedia.org/wiki/IEEE_P802.1p

What traffic are you wanting to prioritize and maybe we can give some recommendations of priority levels to give.

Assigning queue 6 is perfectly fine and usually done when handling voice traffic. It may help to know what traffic you are wanting to give extra priority to. The priority goes from 0-6,lowest-highest priority.

After this the VLAN is tagged over port-channel 1 to our Campus core switch, I am unable to verify if the policy-map is working on the port-channel, because there is no command to show the policy map on a port-channel:

LANStack2#show policy-map interface ? unit/port-type/port/ Enter interface in interface format. So no option to query a port-channel...

CoreSwitchCampus#show policy-map interface 1/g21 in Interface...................................... 1/g21 Direction...................................... In Operational Status............................. Down Policy Name.................................... WGF Interface Summary: Class Name..................................... WGF In Offered Packets............................. 0 In Discarded Packets........................... 0 CoreSwitchCampus#show policy-map interface 2/g21 in Interface...................................... 2/g21 Direction...................................... In Operational Status............................. Down Policy Name.................................... WGF Interface Summary: Class Name..................................... WGF In Offered Packets............................. 0 In Discarded Packets........................... 0

interface ethernet 1/g21 channel-group 1 mode auto service-policy in WGF exit ! interface ethernet 2/g21 channel-group 1 mode auto service-policy in WGF exit ! interface port-channel 1 service-policy in WGF switchport mode general switchport general allowed vlan add 20,30,99-100 tagged switchport general allowed vlan add 1 tagged exit

This document is about VOIP, but it also goes into QoS. The commands wont be the same, but the general info is good. http://www.dell.com/downloads/global/products/pwcnt/en/app_note_11.pdf   When it comes to priority each network can have different needs and goals. Because of this I don’t have a chart or list that shows which CoS we recommend placing certain traffic. I found an example chart on Cisco's site of priority levels that could be given out. But again these could change for each network you run into. http://www.cisco.com/en/US/docs/solutions/Enterprise/Data_Center/VMDC/2.2/collateral/IPVS_files/IPVS-12.jpg Wikipedia also has a similar example chart. "The way traffic is treated when assigned to any particular class is undefined and left to the implementation. The IEEE however has made some broad recommendations:" http://en.wikipedia.org/wiki/IEEE_P802.1p   What traffic are you wanting to prioritize and maybe we can give some recommendations of priority levels to give.

On port 1/g19 we can see the policy is up and receiving offered packets. For the port-channels we can try looking at the output from these commands.

console# show diffserv service brief

console# show interfaces cos-queue port-channel 1

To get a better look at packets and ensure that they have the correct priority set, you can setup a mirroring/monitor session on your uplink port, not the ingress port. Then use wireshark to capture the packets and you will be able to see priority the packet is labeled with. Dell does not have any guides on this, but there are some blogs/how to guides others have written up on this and can be used to guide you.

http://dot1x.blogspot.com/2010/03/sniffing-dot1q-tags-with-wireshark.html

http://ask.wireshark.org/questions/5077/how-to-define-capture-filter-for-qos-traffic

http://netspoon.wordpress.com/2012/09/08/add-dscp-column-in-wireshark/

The most common times you are going to see QoS used is with VOIP. That does not mean its not used anywhere else, but when you see an example of implementation, it is usually VOIP. Here are some links that include examples of such implementation.

http://en.community.dell.com/techcenter/networking/w/wiki/configuring-dell-powerconnect-55xx-series-switch-voice-vlan.aspx

http://www.dell.com/downloads/global/products/pwcnt/en/pwcnt_voice_vlan_support.pdf

But really you can use this for any traffic your company needs a high priority on.

Good job getting it figured out. And thanks for keeping us updated.