Network Printer Disrupting Voice Quality

Hi Everyone,

I am experiencing a situation in which I am not quite sure of what to do or how to fix pretty quickly and I am hoping to acquire as much advice as I can to attack the issue. I have openser/asterisk integration which for the most part works great. Users on other networks share the printing abilities of this network printer positioned on a small LAN, hanging off one user PC to utlize printing capabilities.

The printer was rarely used until recently and since it’s use, we have been experiencing issues of fading in/out with regard to audio (initially I had on idea, the printer was the root of this issue), vast breaking up, when calls are made out thru the PSTN but only whenever the printer is being used, but calls coming in are clear, no voice packet loss or garbled signals.

To provide a little background of the setup of this printer: The printer is using HTTP and it is hanging off of a users PC. The program used when setting up the printer to function in this capacity was the Windows Add Printer program in which the “network printer or printer attached to another computer” was selected which allowed connection to the printer on the internet after inputting a URL. This method was also performed at strategic computers on other networks too.

What can I do in order to use the printer and phones at the same time without the results noted above. I really do not want to discontinue the network printing capabilities. And I cannot ban/control users making outbound calls when the printer is being used because is just not feasible, as many users are miles away on other networks.

Thanks for any assistance.

tlofton

Hi,

I think that the problem could be the network bandwith - when the printer is in use it use almost whole bandwith. to determinate this you can use some sniffer with bandwith metter.

The solutions of this is migrate to one gigabit switch or to switch which support QoS (Quality of Servece - VLAN) or the both solutions gigabit+VLAN. Then you can put the network in one VLAN with lowest priority and the IP Telephoni devices in VLAN with the highest priority.

Hi,

Thanks, sounds like a plan I will implement right away.

tlofton1000

Have you considered using the Ranch Networks RN300? This will solve all your qos problems and divide the network up securely.

Hi gizard,

Actually I am hoping to get recommendations like you have suggested, because until recently, I had no issues with the system. I am just beginning to research vlans, and will be reviewing data from all the recommendations given from my forum peers because I do not know where else to turn for this type of advice. Actually until Asterisk and Openser, I had not known anything about voip technology, so I am open to ideas. At one time, all that travelled through my system was data, and now I want to continue to keep voice travelling through too.

Thanks everyone.

tlofton

Printing is very bandwidth unfriendly traffic. Basically what is happening is that the burst of traffic during the printing job is mixing iwth the VoIP packets. The print job is using very large packets and the voip is using very little packets. Imagine your self riding a motot scooter on a freeway full of large fast moving trucks. Your packets are getting mixed in with the larger data packets and you are getting jitter (variable latency).

How yo solve this depends on how your network is put together and and what type of phones you have and of course the size of your problem. Grabbing a box off the shelf is not always the best way to solve a networking traffic problem, you need to really look at what has caused the problem.

You post didn’t indicate if you are using soft phones on the PC with the print server or dedicated phones.

VLAN’ing is an excellent way to address these issues in the LAN environment. Throuing a Gig switch at the problem is not really solving hte problem but putting it off until more truck enter the freeway and your scooter gets lost again.

If you are suing softphones then make sure the PC has the horse power to server the printing and the softphone.

So many choices, so many possible solutions :wink:

Hi Scott,

Thanks for the response. Actuallly, I have hubs and switches with several different networks. But I will discribe the one LAN with the network printer which services printing for all networks and users. I will start with the router. The router connects to a dumb switch that provides the static ip addresses while the other end connects to the CPU unit of the machine with the printer, then on this same router is a Linksys PAP2/PAP2T with a phone/fax and a phone, and a Polycom 500 Sip.

Actually the other networks, have no printer in the mix but all of them have dedicated phones connected to routers here and there.

Thanks for any and all advice.

tlofton

If I follow your configuration you have

Workstation with print server
-> Printer
|
Router
|
LAN Switch
|
±Linksys PAP2
|
±Polycom IP500

Are all of these connections 100 MBPS Ethernet or better? 10 MBPS can be bad.

Is the voice crossing the router and isthis the quality issue?

When you say voice quality os poor can you quantify this. Basically is this jitter or dropped packets?

Hi,
It is more like this, but on a little larger scale, because there are a few more hubs, devices, w/s in the diagram just not shown in the diagram (also I may have said earlier that the pritner hangs off the user PC, but I forgot I moved this a long time ago to hang off the server instead):
-------------------------- cable
------------------------------|
------------------------dumb switch
-----------------|--------|---------|----------|-------------------|------------------|

-------------router------ --------- -------Router-----------server------------server
-------phones– -------- ---------

-----------------w/s—server server
---------------------------|
------------------------printer

Plus there are other networks on the outisde that use our voip services too. There are a total of three networks in our buiding with various machines and devices on them. The connections are 100MBPS . Yes, voice packets are crossing the router. In fact, system works perfectly until someone decides to use the rarely used printer. During these brief periods, if you’re on a receiving end of a phone, you can hear the voice packets trying to go through but the sound - let me try to explain - it sounds like so: quick voice sound, gurgle- garble sound, some voice again, stop, gurgly gurgly sound, some voice, stop gurgle-garble, etc, and constantly breaking up. Then when the printers stops, voice comes on thru clear as a whistle. Again, this only occurs when I initiate call, when recieivng calls from the PSTN, it is normal whether printing or not.

Actually at this time, I am considering a different setup for the printer rather than sharing it through Internet printing.

However, I am open for recommendations that will not disrupt the system too much.

Thanks…
tlofton

Hi,

I resolved this by just removing the printer from hanging off the server and from using internet mode printing and now it hangs off of a w/s regularly. No more bandwidth issues as noted above. All calls respond normally in/out, whether printing or not.

Thanks,

tlofton

Well just FYI:
In a VOIP environment there is no place for “DUMB” switches, and absolutly no place for HUBs.

You need to have a switched environment with atleast L2 QOS support, and preferably L3 QOS. Along with Vlans.

This is what I do for HP procurve equip:

Basicly you want to VLAN you entire phone system all to its self, and enable QOS on those phone ports priority 7(highest). DONT forget about the asterisk server :smile:

Make printers and servers and your routers Priority 5(Second Highest).
Make your WiFi points a 3 (second lowest)
Make your workstations 3 or 0 (second lowest or lowest)

[VOIP - QOS 7]
[Servers, Printers, Routers	- QOS 5]
[Wifi points - QOS 3]
[Workstations - QOS 3] 

By doing this your Voip traffic will be the most important info on the line.

Upgrading to gigabit will only make your problems worse - throwing more bandwidth at the issue is not a smart move. cause if you servers all have gigabit connections they will once agial take over your network, and leave your Voip hardware to fend for them selves…[/code]

Hi Danursuline,

Thank you for the information and explanation of “How To” as well. As noted earlier, I need responses like this from forum peers as this part of the equation (Vlan - QOS) is very new to me. I have started looking into various vlan products and deciding on which one is also hard, as there are so many to choose from, and trying to understand the literature is a bit tough too. Also, from the looks of my system, will I just need one Vlan? Will the Cisco 2950-12 be sufficient, or 2950 WS-C2950T-24, WS-C2950T-24 Switch, etc.? I do not have T1, and I am not qiute sure what the suffix 12, 24, 48 represent on these switches. Also, I read about particular Cisco models that add on to the 2950 to control dynaimc bandwidth. So, I am looking for recommendations on which ones to purchase for a setup similiar to the diagram in prior thread above.

I noticed you mentioned you use HP equipment, what type of Vlan do you use (ie. model number) in your setup?

TIA.

tlofton

[quote=“tlofton1000”] … am not qiute sure what the suffix 12, 24, 48 represent on these switches…
tlofton[/quote]

Disregard this question.

tlofton

I would go with HP Procurve:

Reasons:
They support POE and Vlans, and QOS
They HAVE A LIFETIME WARRENTY for all their ProCurve products! Free software/firmware updates for life, and support.

If anything breaks on your switch when you have it its covered, if they dont make that switch anymore - you get an upgrade :smile:

Here is Cisco’s default warrenty:

And then you have to buy SmartNet contracts with them…

ALSO

They only give you a 5 year on the fan and PS, but if it is EOL then your SOL :smile:

Just piece of mind - Cisco has a big name and a big price, and for what your doing its Overkill… IMO

Go with HP, look at the 2650-pwr or the 2626-pwr if you interested in POE, they do L2 and L3-QOS
[/b]

Tlofton,

Sorry I haven’t been around in a few days. I have a customer that has a setup like you and I’ll be using the Ranch Networks for that as well. I’m using their RN20 aplliance for this as it does the firewall, qos, etc. Plus it is already a router and switch (switch on this one has 12 ports). These things blow away cisco on what they do, price, etc. I’m very happy with them. Contact Brett over there. He’s a good guy and knows his stuff. If you need any help, let me know.

Hi,

Well, I will be reveiwing both HP Procurce and Ranch Networks. I must say Danursuline that I do like “Lifetime Warranties” and the research w.r.t. the literature you provided on Cisco’s limitations in this regard is very helpful.

tlofton

Hey guys, just doing a bit more research on the HP Procurve and Ranch Networks equipment. These two things are different beasts. After looking more at the Ranch networks device, check this out. Pretty cool.

The Ranch Networks can be used two ways. Either in the front of your network, or if you already have everything in place, just use it to make Asterisk reliable, secure, expandable. Nice thing is you can provide QOS on a per call basis. How sweet is that!

From what I figured out, this is what you can do:

RN20 (firewall, router, switch, vpn, qos, NAT Traversal, media bridge) -->

Divide network: Phones, printers, dev team, sales team, web server, * server, database server, etc. -->

Instead of your typical vlan, use ranch networks secure zones. This not only firewalls the outside world, but also firewalls each segment of your internal network. You can now define the access everyone/everything has from each other on your network from one box all while providing QOS. Since all data flows through their box first, the box can control everything! This is really sweet.

You get all of that plus you now can provide Asterisk high availability, Asterisk clustering, per call firewall, per call QOS. Another big thing is the media bridging. We have found our * server can handle 50 or so simultanious calls (about 150 users total). The ranch networks box takes the load off Asterisk and onto their box. This allows 200 simultanious calls (600 users in our case).

In the end, this ranch networks stuff seems to be the answer. Protect your network, provide redundancy and scalability for Asterisk, and have your NAT traversal and QOS. All in one box with a GUI. The more I research ranch, the more I wish I would have found it sooner. Let me get my mits on the RN20 next week and I’ll report more of my findings.

[quote=“gizard”]
From what I figured out, this is what you can do:

RN20 (firewall, router, switch, vpn, qos, NAT Traversal, media bridge) -->

Divide network: Phones, printers, dev team, sales team, web server, * server, database server, etc. -->

Instead of your typical vlan, use ranch networks secure zones. This not only firewalls the outside world, but also firewalls each segment of your internal network. You can now define the access everyone/everything has from each other on your network from one box all while providing QOS. Since all data flows through their box first, the box can control everything! This is really sweet.

You get all of that plus you now can provide Asterisk high availability, Asterisk clustering, per call firewall, per call QOS. Another big thing is the media bridging. We have found our * server can handle 50 or so simultanious calls (about 150 users total).

In the end, this ranch networks stuff seems to be the answer. Protect your network, provide redundancy and scalability for Asterisk, and have your NAT traversal and QOS. All in one box with a GUI. The more I research ranch, the more I wish I would have found it sooner. Let me get my mits on the RN20 next week and I’ll report more of my findings.[/quote]

Woe Silver

Could you please explain how

a - The ranch networks box takes the load off Asterisk and onto their box. This allows 200 simultanious calls (600 users in our case) ?

What load is it taking off the Asterisk box ???

b) now can provide Asterisk high availability, Asterisk clustering

Errr- How is the ranch box suddenly making this possible ???

You may have found the HOLY GRAIL, but could you explain a bit more WHY the Ranch box is bringing any more to the table than the HP ??

THX

gizard, just curious, are you on Ranch Network’s payroll? there’s nothing wrong with that, just wondering.

considering that all 3 posts have raved about Ranch kit, i was starting to wonder that too :wink: