Configuring QoS for VoIP on HP Procurve switches

[m_j]

Hi all,

finally signed up on these forums!

I have read through some of the material regarding configuring QoS on HP Procurve switches but i still don't exactly understand which type of QoS configuration i should use for our enviornment.

We are using a Avaya IP Office 500 VoIP system with SoftPhones (VoIP client installed on the clients).

The problem is the quality of VoIP internally in our network, echoes and lost calls. I am, as we speak, going to check two simple solutions (from the Avaya community):

1. Check if the VoIP system is grounded
2. Set static port speed to 100mbit on the port on the 5406zl instead of Auto neg.

This aside we still want to QoS prioritize the VoIP traffic internally..

To the network configuration and my questions:

VLAN 2 (Internal LAN)

How it's connected:

Avaya IP Office 500 LAN interface -> HP Proc 5406zl port A1 (untagged VLAN 2)

HP Proc 5406zl port A2 (tagged VLAN 2) ->
HP Proc 2810-24G Port 23

HP Proc 2810-24G Port 24 (Default VLAN untagged) -> HP Proc 2810-48G Port 48 (Default VLAN untagged)

HP Proc 2810-48G -> Default VLAN untagged to all clients

Sorry if my topology explanation is messed up but i think you might get it.

The traffic, if i use a random network traffic sniffer like Wireshark, from and to (?) the Avaya IP Office 500 is tagged with a DSCP value of 46 (101110, Expedited Forwarding) atleast on the the actual voice traffic (RTP).

DSCP value of 46 and priority of 7 is configured default on the switches as i understand, on the Avaya everything is default regarding QoS (DSCP value: 46 etc.).

How do i, with my scenario regarding switches, set up QoS in a more or less correct way? I have no seperate VLAN used for carrying VoIP-traffic to and from upstream devices. Is device-priority or interface (source port) priority the way to go here?

Btw this document is great:

ftp://ftp.hp.com/pub/networking/software/2810-AdvTrafficMgmt-July2007-59914733.pdf

After reading the document above i feel that the there's too many choices for setting up QoS and that it's kind of confusing for a novice.

Thanks!

P.S. This thread has been moved  from Switches, Hubs, Modems (Legacy ITRC forum) to ProCurve / ProVision-Based. - HP Forums moderator

[Corey Dalton]

You should really have a VLAN for each VoiP segment because the traffic is prioritized by VLAN

Example

vlan 112
name "12_Flr VOIP"
untagged 50
ip address 172.18.12.2 255.255.255.0
qos priority 6
tagged 3-49

Turning on QOS on a mixed voice and Data VLAN is no different than not turning it on. Just make a voice VLAN and Tag the uplink for the vlan on the switch and add the new VLAN to the next hop router and tag it on that port too.

[m_j]

Hi,

thanks. The enviornment was configured without a seperate VLAN for the voice traffic from the beginning and changing it from the current configuration is a bit tricky but i will try this!

[Lemmy Kilmister]

how many users do you have on your voice vlan?

I would argue that if you are properly segmented via vlans, there's no need to do QOS internally on your switch.

[Cajuntank MS]

Heres a link below relating to Procurve and Avaya platforms. (see pg.9 about QoS configuration on the Procurve side)
https://support.hpe.com/hpesc/public/km/search#q=Procurve%20and%20Avaya%20platforms&t=Documents&sort=relevancy&layout=table&numberOfResults=25&f:@kmdoclanguagecode=[cv1871440]&hpe=1

And as stated already, make sure you have dedicated VLANs created for voice traffic only.

[Gerhard Roets]

Hi m_j

Do you perhaps have a "show running" and "show system" floating about for me to peruse for both switches?

[ahoyt12]

Can you please explain why mixed data and voice with QoS turned on is useless? When would you use the QoS for voice? Thanks

[Fred001]

Hi all,

we use Lync phones and Lync clients and tag packtes with DSCP values already when they are sent. After reading some manuals it's still not clear to me, how I can assure that tagged packets will be priorisized on HP Procurve switches. We have no VLANs and do not tend to use them. Besides this, it will not make sense as far as we us the Lync Softwareclient.

What has to be done on the switches to accomplish this task?

Thank you.

[Vince_Whirlwind]

QoS only really does anything useful if you have congestion.

Normally on a LAN, you don't have any congestion as you scale your inter-switch links to avoid it.

Across a WAN, on the other hand, you tend to have limited bandwidth and this is where QoS actually does something useful.

[natashajolly]

Very good article...It give complete information about network switches...Good stuff for persons who work in networking..

voip switch

[tjbradford]

following up on this from historic post's 

QoS can be applied at the end device or on the switch. 

Applying it on the switch on a single vlan will result in ALL traffic getting the same priority 

Applying it on the end device such as the phone tagging it or in the case of a soft phone then it is already tagged by that software when leaving the PC - NOTE : Not all PC packets are tagged, just the voice ones. 

those tags whatever they happen to be need to be matched on the switch so that when the switch sees these tags it gives them a class of service, e.g. data = best efforts where as voice = has a greater priority so is put to the front of the Q for sending as it is time sensitive. 

you need to make sure that however big or small your network, every interface between the caller and the recevier knows what to do with the tags, if you miss off a switch or interface that should be seeing voice tags and isn't then any traffic passing through that interface is ordered by time of arrival and not by importance of Q "jumpers" which is basically what vocie packets are. 

you should be able to flood a network with data and still make a clean call, this is because the buffers in the switches will hold as much data as they can until the link is is able to fit them on the wire inbetween vocie packets, you can set % 's on cisco kit but i'm unsure of this on HP, the Gist is that you can reserve 10% for voice and if no voice is using the link then data can dip into it, however if you then start making calls x% upto the maximum of 10% is garenteed to be pushed to the front of the Q - if you go above this then the call quality is best efforts. 

Long and short - check you end to end QoS and make sure every link is aware of what to do with those Tags, it sounds like something is missing. 

start with two phones on the same switch and head down the route towards the problematic end user switch. 

or port mirror and sniff the flows, you should see the tags but the switch might not know what to do with them.