09-24-2008 04:53 AM - edited 03-03-2019 11:40 PM
Hey guy's just curious for suggestions on this.
We have remote sites connected by point-to-point full T-1's. We are running voice (IPT) over the T-1's and have prioritzed the traffic as ef as expected. Now heres the question. We have a critical business application that needs high priority almost as much as the voice traffic, but I don't want it interferring with the voice traffic. What would be a good DSCP value to mark the applications traffic?
Thanks
09-24-2008 05:16 AM
normally your voice is given DSCP 46 (ef)= ip precedence 5 and your business app dscp 16 = IP precedence 2.
Francisco
09-24-2008 05:17 AM
Depending on what class you have defined for voice signalling you could use af21 or af31. You would like the application lower than signalling since you wouldn't want the application to interfere with voice signalling either. If this is the only application which needs to be preferred af21 would suffice, but if you really consider the application to be close to voip af31 would be more suitable unless af31 is already used for voice signalling.
09-24-2008 05:30 AM
Currently we do have signaling as af31. If we more to af21 for the application will this hurt signaling?
Thanks
09-24-2008 05:39 AM
If we have signaling at af31 and desire to leave it would af41 for the application proiritize it enough?
Thanks
09-24-2008 05:44 AM
based on the dscp values i gave above AF31 is is fine for singaling and AF21 for your apps.
09-24-2008 05:48 AM
So if we currently have signaling at af31 we should leave it and give apps af21? Or are you saying to change the signaling value?
Thanks
09-24-2008 05:51 AM
Brandon,
no need to change the values. leave singal as AF31 and you apps as AF21.
francisco
09-24-2008 05:53 AM
Great! I'll try that.
Thanks
09-24-2008 12:23 PM
francisco,
Would this config work for governing my voice and critical application?
class-map match-any Voice-Calls
description Voice-Calls
match ip dscp ef
class-map match-any Voice-Call-Control
description Call-Control
match dscp af31
class-map match-any Critial-Application
description Critical-Application-Traffic
match access-group name Critical-Application
class-map match-any Telnet-Traffic
description Telnet-SSH
match protocol telnet
match protocol ssh
!
!
policy-map QOS
description Traffic-QoS
class Voice-Calls
priority 282
class Critical-Application
bandwidth 600
set dscp af21
class Telnet-Traffic
bandwidth 64
class Voice-Call-Control
priority 64
class class-default
fair-queue
random-detect
Thanks
09-24-2008 09:13 AM
See http://www.cisco.com/en/US/technologies/tk543/tk759/technologies_white_paper0900aecd80295a9b.pdf
PS:
Just marking doesn't always guarantee the traffic actually obtains higher priority. Conversely, on a p-2-p T-1, you really don't need to mark to deliver different service priorities.
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