QoS suggestions?

[digi076]

Hi all,

We have a lot of setups with Cisco 887va VDSL separated by a data EVC and Voice EVC. This is tagged traffic and thus created 2 subinterfaces on ethernet 0. These connect to dialer1 and dialer2 respectively. Most networks are relatively simple with just one managed switch behind the router where vlan1 is data and vlan2 is voice. 

As they are separated circuits with their own allocated bandwith on ISP side, is it still necessary to implement QoS? 

We still have customers with choppy calls. Do you reckon its wise to implement a policy map on both dialers outbound?

Suggestions/tips are welcome, thanks!

Best regards,

Will

[Georg Pauwen]

Hello,

in general, especially if you have choppy calls, QoS for VoIP is a good idea. What are you using for voice (e.g. Cisci IP Phones) ?

[digi076]

Hi Georg,

Pbx is an Asterisk based one.
End-users phones are mainly Yealink.

If the DSCP value is mismatched on the switch (L2) will it be put in the class default maybe?

[Georg Pauwen]

Hello,

I think Yealink uses UDP 5060 or 6060 by default. If you have more than one phone, as far as I recall you have to change the port used (to e.g.5061 or 6061 and so on) on each phone.

Below is a sample QoS (as stated you might have to configure a range of UDP ports):

access-list 101 permit udp any any eq 5060
access-list 101 permit udp any any eq 6060
!
class-map match-any VoIP_Class
match dscp ef
match dscp af31
match dscp cs3
match access-group 101
!
policy-map VoIP_PM

class VoIP_Class
priority kbps
!
class class-default
fair-queue
!
interface Dialer0
ip address negotiated
service-policy output VoIP_PM

[digi076]

Thank you, Georg. I will look into it tomorrow :)

[paul driver]

Hello

---

@digi076 wrote:
If the DSCP value is mismatched on the switch (L2) will it be put in the class default maybe?

---

Question is -
Do you have mls qos enabled on the switches?
Are you exceeding your CIR on the voice EVC?
What Is the isp expecting to receive in interns of Classification/Marking of your voice traffic?

[digi076]

hey paul,

it's no Cisco switch unfortunately, mostly HPE ProCurve series. 

It's unlikely the CIR is exceeded on the voice EV. I will need to check though. 

I will check the values on the PBX side, thank you. 

[paul driver]

---

@digi076 wrote:

Hi all,

We have a lot of setups with Cisco 887va VDSL separated by a data EVC and Voice EVC. 

As they are separated circuits with their own allocated bandwith on ISP side, is it still necessary to implement QoS? 

We still have customers with choppy calls. Do you reckon its wise to implement a policy map on both 

---

If you have separate data and voice circuits  then your data traffic won’t be mixed with the voice 

if you are not exceeding your cir rate for your voice evc and still experiencing jitter one reason could be your phones are not marking the voice traffic accordingly inline to what the isp is expecting to receive and as such it getting dumped into a default catch all class.

however if you are marking your voice traffic correctly and are exceeding your cir rate tthen applying  qos would be a good idea

same rules apply to your data evc

Laslty  I would suggest either way that you apply some shaping to either circuits inline with your agreed isp cir rates

[digi076]

Hello,

This is an example of a customer who is using voice on the data vlan, so I need to match on dialer 1 which is the internet evc.

The upload cir is 2mbit. 

---------------------

class-map match-any VOICE
match protocol rtp audio
match dscp ef
!
policy-map queue
class VOICE
priority percent 80
class class-default
fair-queue

policy-map shape
class class-default
shape average 2048000
service-policy queue

Int dialer 1

service-policy output shape

----------------------------

There is a bandwidth statement on dialer1, but that counts for download only right?

is the above config correct?

thanks!

[Georg Pauwen]

Hello,

you don't need the bandwidth statement. The policy looks good, I would just make one small adjustment (marked in bold):

class-map match-any VOICE
match protocol rtp audio
match dscp ef
!
policy-map CHILD_POLICY
class VOICE
priority percent 80
class class-default
fair-queue
!
policy-map PARENT_POLICY
class class-default
fair-queue
shape average 2048000
service-policy CHILD_POLICY
!
interface Dialer 1
service-policy output PARENT_POLICY

[digi076]

thank you Georg, much appreciated. 

I tried to adjust, but gave me this: fair-queue not allowed in a parent policy

About the bandwith

I see the priority % is based on the shaped average in parent policy so that's fine indeed. 

Thanks.