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Packet Prioritization/QoS

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I am looking for a reasonably affordable and reliable way to provide packet prioritization within my LAN, based on TCP/UDP port.

For example, I want VoIP traffic to flow through my network uninterrupted, without being squelched by somone copying a large file to the server.

I think this would be accomplished by a switch with special capabilities. I have been trying to figure out which brands/models will do this, but I can’t make heads-or-tails out of “QoS”, “802.1p”, “Layer 2 switching” and the other technologies and standards available.

Ultimately, I am looking for a recomendation of a specific brand and model of device, but I would also like to know which technology does what I am asking, so I can make an informed decision.

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Reply To: Packet Prioritization/QoS

In reply to Packet Prioritization/QoS

Have you considered dedicating an entire lan to VoIP traffic? I don’t know your layout, so may or may not be an extreme measure.

You can also use a proxy for the VoIP traffic.

Here’s a solid reference on gatekeeper technology.

http://www.cisco.com/warp/public/788/voip/voip_gw_gk.html

Reply To: Packet Prioritization/QoS

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I’ve peer mailed you… if you are looking for a solid management interface to query the server… let me know.

Include your vital stats for the network.

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Not what I was looking for.

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Not sure of the size of your environment, but general comments below. Contact me direct on email if you want to know something specific.

A must for VoIP in the LAN environment is a Layer 2 Switch based architecture. Any type of hub based LAN will only work in very small implementations.

The Switches must support 802.1p and q. This will give you VLAN and Prioritisation capability. VoIP phones are best placed in their own VLAN, separate to PCs, printers, servers, etc. This is not essential, but strongly recommneded for hardware VoIP devices. VoIP VLANs are then given top priority over all other VLANs.

When designing the infrastructre any shared up links must be Full Duplex. If you have Half Duplex anywhere in the VoIP path there is the possibility of temporary congestion, which will kill your Voice call.

Good devices – Cisco, Nortel, 3COM.

Reply To: Packet Prioritization/QoS

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Helpful.

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Really depends on several factors but I will stay general to your question. Since I am a CISCO Biggot, then I recomend CISCO of course. The bottom line catalyst 2950 will support CoS (Class of Service). If you have any remote offices and need to do QoS (Quality of Service)on your routers. If the traffic is going to be voice traffic then the bottom Cisco 1751V router is needed with IP Plus IOS. Typically you will segment your VOIP traffic on a seperate VLAN and run CoS on the switches and QoS on the routers. The size (horsepower) of the switch and router is dependent upon your current traffic and the number of devices. The above mentioned will work on a small to med size business. A short design would be a catalyst 4000 series Core switch and then the Catalyst 2950’s hanging off of them conected via GBICS. The 2950’s can also be used in data closets down the hall. Would need more info to get more specific and the above is a Cisco minimum.

TL McBrayer CNE5 & 6, CCNP, CIDS, CXE

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Mildly helpful.

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http://www.voip-info.org/wiki-Asterisk+QoS

Some good reading here.

Lee

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Hi, my name is Gabriel. If you call me Monday (28th) on this number (800) 201-9199 ext. 7719 , I will have one of our Techs give you a call and give you some one on one consulting and tips on how you can do that at a minimal cost.

Gabe

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Reply To: Packet Prioritization/QoS

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Hi SuSu
I don’t have an answer for you, as I’m in the process of dealing with a 3COM VoIP problem on my
LAN. I read MBATTY’s comment and I sure would like to get his e-mail address to correspond with him on this subject. My network is a mess since this VoIP system has been installed.
Long story. 🙁
rrayner@puhsd.k12.ca.us

Thank You

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VoIP can be wonderful addition to the network or it can be a entire nightmare. The best way to avoid this is by conducting a network impact analysis either by educating yourself or from a reputable firm specializing in VoIP.

I sincerely hope you have sent the time assessing your network environment before implementation. It is a nightmare to undue the problems that arise from a VoIP implementation.

Greg

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We ARE the reputable firm specializing in VoIP. Or at least we will be.

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Please DON’T dedicate an entire LAN to voice. The whole point of VoIP is to have a CONVERGED NETWORK!!!! I guarantee you’ll want your PCs to communicate with the phones for management, CTI or even just softphone at some point. You’ll also have double the cabling, double the switch ports etc. etc.
Understand what your chosen VoIP system does with priority. You’ll have IP phones and system devices. These will label traffic they generate with some kind of priority. It could be 802.1P, (priority in the ethernet part of the packet) and/or priority at the IP layer. There are a number of different forms of this – IP Type of Service (ToS) – also known as IP Precedence – or Differentiated Services (DiffServ or DSCP).
If you’re only sending the VoIP traffic over an ethernet LAN, stick to using 802.1P – if that’s what your VoIP stuff labels with. If you’re going over a WAN you might need to do dot1p on your LAN switches and DiffServ on your WAN routers.
Talk to a company who are experts in running voice over data networks and, most importantly, get them talking to the manufacturer or reseller of your VoIP solution. Tie them in to working together to offer a solution that will work for you.
Most modern managed switches from major vendors (Cisco, 3Com, Extreme, Nortel, HP etc.) have capabilities in the kinds of areas mentioned, but many of them will need configuring – don’t assume they’ll prioritise your traffic right out of the box. Ask switch vendors to provide case studies and reference sites for your chosen VoIP system working on the switches they’re trying to sell you. Make sure you speak to the end-user in each case to see whether it worked and how easy it was to set up and manage.

I notice you didn’t mention Power over Ethernet, which is something you should look at with IP phones, in which case the standard to look for on the switches is 802.1af but make sure your IP phones support it!

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Best answer here. Thank you.

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This question was closed by the author

Hacked Linksys Router QoS

In reply to Packet Prioritization/QoS

I use a hacked Linksys WRT54GL Router I changed the stock firmware to the Tomato Firmware and that has QoS Built in yes the router is old and only dose 100mb/s Ethernet and 802.11b/g but its fine for what I need. Its cheap and dose the job I got mine for under ?45 online with P+P.

[Author]

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