12-28-2007 09:58 AM - edited 03-03-2019 08:04 PM
Probably a dumb question. I have one policy map doing traffic shaping on an outgoing interface. I want to create another policy map for voip traffic and apply it to the same outgoing interface. Can I just use the service policy output command for both maps, or should I add the shaping command to the end of the voip map. In what order would the items in the policy be applied if it were all wrapped up into one.
12-28-2007 10:36 AM
OK. Just one outgoing or incoming policy map per interface. Now my question is in what order are the class maps looked at? Should I do the voip first and then do the shaping?
12-28-2007 04:15 PM
I believe the classes are looked at in the order specified. Put your VoIP (LLQ) class at the top, other bandwidth-limiting classes after that, and then the default class.
12-28-2007 04:29 PM
Hi, what you want is a "childed" service policy, shape first, then priority for voip. See:
http://www.cisco.com/en/US/tech/tk543/tk545/technologies_tech_note09186a00800b2d29.shtml
there was a better one, I couldn't find it anymore. Just look at the "PPPoE" example, even if you are not using PPPoE.
Hope this helps, please rate post if it does!
12-28-2007 06:21 PM
So you disagree with the first response. Looking at that example, it looks like entering in those commands would give you 2 separate policy maps. When applied in the example for pppoe shown, it looks like just one is applied to the interface. How would it know to use the child-queueing policy, which seems to be just a name for a policy-map?
12-28-2007 10:32 PM
Both the above posters are right.
You can have multiple policy maps defined on a router but only one can be applied to the interface
Paolo's example is that of a nested policy, wherin the parent policy will be applied to the interface and will be referencing the child policy defined under it
HTH
Narayan
12-29-2007 04:30 AM
Hi, is not that I disagree, it's that it depends what you want to do.
If you are trying to do QoS on an ethernet for voice, you will definitely need a nested policy with shaping at the link speed of the next slower circuit.
If you are just setting shaping, remarking, etc, for "general purpose", then a regular policy is OK and order doesn't count.
Hope this clarify that a bit.
01-01-2008 06:51 AM
Will be using for voice. Thank you for clarifying. How does this look.
class-map match-all Voip-Control
match access-group 111
class-map match-all Voip-RTP
match access-group 110
policy-map shape100mb
class class-default
shape average 100000000
service-policy qos-policy-voip
policymap qos-policy-voip
class Voip-RTP
priority 800
class Voip-Control
bandwidth 8
class class-default
fair-queue
on interface to MPLS Cloud
service-policy output shape100mb
01-01-2008 09:23 AM
config looks good
btw, how many calls do you wanna support?
The values for priority and bandwidth should be in accordance to that (control bandwidth seems way too low)
A single G729 call would take around 24K
HTH
Narayan
01-01-2008 10:52 AM
Here are the access lists from the same config, forgot to post before.
access-list 110 permit udp any any range 60000 63071
access-list 110 permit udp any range 60000 63071 any
access-list 111 permit udp any eq 3455 any eq 3456
access-list 111 permit udp any eq 3458 any
access-list 111 permit udp any eq 4000 any
Each site will have around 20-25 ip phones. 10 would be the most in use at one time from any site I would guess. Is their a best practice or common setting for the priority and bandwidth commands. Definitely can change if you think that would be best. 20 mb for 3 sites, 100mb from the other 2. PBX is in one of the 100 mb sites.
01-01-2008 11:31 AM
Hi,
You should configure the shaping value to be the circuit speed of the next upstream link, for example 640000 for a DSL, 1500000 for T1, etc.
Then, cisco voip by default uses the correct dscp ef marking, so you can replace all the udp/port matching ACL with simply "match ip dscp ef".
01-01-2008 02:48 PM
Another thing. Try asking your MPLS provider, if they honor dscp in your traffic. If they do, you don't need to do anything.
01-03-2008 09:27 AM
Will do. You mentioned that the bandwidth and priority settings seemed low. Say you were going to have a maximum of 15 calls at any one time, and had 20 mb of bandwidth to play with. What would you recommend for settings in that scenario. Bandwidth command I belive is the amount of bandwidth allocated per call?
Priority command I believe is the amount of bandwidth guaranteed to marked traffic during congesiton. If I have 20mb, give 8mb for the priority command. Let me know what you think, I appreciate your feedback.
01-03-2008 11:17 AM
Hi,
what matters is the shaping parameter, 20000000 if you have 20 mbps guaranteed throughput, and the priority parameter, that is cumulative for all calls or marked traffic as you say.
15 times 80 Kbps, makes 1,200,000 that is written as 1200. You can omit the control class, worry not, control traffic will work anyway.
02-11-2008 09:18 AM
Thanks again for all of your help. When applying this policy, should I apply to the subinterface for the voice vlan, or can I apply it to the main interface going out to the mpls cloud.
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