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November 21st, 2013 00:00

Just an short update: I think my configuration is working fine. I figured out that the ping reply delay has more to do with the end device then with the switch configuration :) 

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November 12th, 2013 23:00

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...

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November 13th, 2013 23:00

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.

Thanks for confirming my thoughts. So my configuration seems to be okay. Now I would like to verify if DiffServ is working... The traffic is coming from interface 1/g19 on the core switch of the datacenter. The packets meets to the policy-map I've created (VLAN 30), please take a look in the 'In Offered Packets': CoreSwitchDataCenter#show policy-map interface 1/g19 in
Interface...................................... 1/g19
Direction...................................... In
Operational Status............................. Up
Policy Name.................................... WGF
Interface Summary:
Class Name..................................... WGF
In Offered Packets............................. 8971
In Discarded Packets........................... 0

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...
If I try to view the offered packets on the interfaces them selves, there is nothing to see because everything is configured on the port-channels:
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
Although it's definitly configured to match packets of this vlan:
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.

Thanks for the information, but I think I understand how coq works. I just need some practical examples of how it will work on PowerConnect switches. Like you did on the assign-queue command :) Any idea's of how to verify if DeffServ is working?
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