Same here less than 50 VOIP phones on the same LAN/VLAN and only had QOS and they worked fine.
Jon On Fri, Dec 18, 2009 at 4:58 PM, wjh <[email protected]> wrote: > I agree about being surprised that you would have issues on a small > network. Vlaning may help, but we have clients with similar setups that > have 20 to 80 phones with no phone traffic vlan. we typically use asterisk > and snom or polycom phones though. > > I'm not our VoIP guy, but I would also ask questions about the codec being > used. You can choke your bandwidth with an inefficient codec. > > Bill > On 12/17/2009 8:17 PM, Brian Desmond wrote: > > *+1 on Aaron’s reply.* > > * * > > *My only observations are that if you have an existing DHCP > infrastructure, I would run DHCP for the VLAN(s) involved with the phones on > there rather than as a second parallel DHCP environment. You’ll need the > router to forward the broadcasts for this to work but that’s pretty > standard.* > > * * > > *Fundamentally I’m a little surprised that something that small and with > the traffic profile you described is giving the VoIP traffic a hard time. I > almost have to wonder if something simple here might be compounding the > problem like a speed/duplex mismatch. * > > * * > > *If it were me I’d reconsider how much you trust the consultant at least > in this space – the VLAN/segmentation stuff is pretty 101 level stuff. I’d > expect a consultant to have some clue about it if he’s going to offer advice > in the space. * > > * * > > *Thanks,* > > *Brian Desmond* > > *[email protected]* > > * * > > *c – 312.731.3132* > > * * > > *From:* Evan Brastow > [mailto:[email protected]<[email protected]>] > > *Sent:* Thursday, December 17, 2009 7:02 PM > *To:* NT System Admin Issues > *Subject:* RE: VLAN question > > > > Wow guys… seriously.. what a great list. Aaron… wow! I’ve never read > something that comprehensive without paying for it! Thank you so much to all > you guys for steering me in the right direction! I’ve learned so much in the > last hour… lol > > > > Thanks again… I’m off to go work on VLANS and QoS. Heck, last time I knew > anything about real networking, VLANS was a typo J > > > > Evan > > > > > > *From:* Clayton Doige > [mailto:[email protected]<[email protected]>] > > *Sent:* Thursday, December 17, 2009 7:47 PM > *To:* NT System Admin Issues > *Subject:* RE: VLAN question > > > > Great post J > > > > *From:* Rohyans, Aaron > [mailto:[email protected]<[email protected]>] > > *Sent:* 18 December 2009 00:37 > *To:* NT System Admin Issues > *Subject:* RE: VLAN question > > > > Short answer – yes! > > > > What your phone vendor is referring to is simply VLAN segmentation and it > is an **essential** part of a well performing IP Telephony system. The > phones likely have the capability to run an 802.1q trunk to your HP switch. > What this essentially does, is allow the phone to ‘tag’ its traffic using > 802.1q headers for a specific VLAN (i.e. your new Voice VLAN) as well as tag > it with a specific Class of Service (CoS) value (i.e. 802.1p – CS3 or CS5)… > blah blah blah blah blah. The PC sends it’s traffic normally (un-‘tagged’) > through the phone and into the ‘Native’ VLAN of the switch (Native = your > Data VLAN). Now, what this means to you is that your PCs will operate > normally as they did before, but your phone will LOGICALLY separate its > traffic from the rest of your network. Although it rides over the same > cable, the traffic will be logically separate as it enters/leaves the > switch. The fact that your phone tags its traffic with CS3/CS5 (Media = > CS5, Signaling = CS3) also allows you to establish proper Quality of Service > (QoS) trust boundaries as well as provide proper Queuing/Policing/Priority > mechanisms to ensure that your phone traffic maintains precedence over your > data traffic. Remember, phones are unforgiving to network latency/packet > loss. So, anytime we have the opportunity to ‘screw’ over normal PCs by > shoving phone traffic ahead of them – we should do it – their traffic is > much more forgiving to latency/packet loss. > > > > Advantages to what your phone vendor is proposing: > > · Creates a separate broadcast domain for your phones – phones are > very “chatty” (no pun intended J) and tend to broadcast A LOT… why should > your PCs have to listen to these broadcasts when it doesn’t pertain to them > – and vice versa? > > · VLANs provide a decent level of protection in the event you > suffer from a broadcast storm on one of your subnets – i.e. you loop your > network by accident and the most you’ll do is kill that one VLAN. As it is > now, if you were to accidentally loop your network, you’d kill both phones > and PCs. With VLAN segmentation, hopefully the most you’ll kill is your PC > side – leaving your phones unharmed J > > · The ability to build in QoS mechanisms (YES, you NEED QoS even > in a LAN environment) based on 802.1p tags or VLAN assignment (although, you > **could** provide QoS without VLANs using 802.1p tagging… but that’s no > fun J) > > · Easier traffic management (even for traffic outside of phones – > perhaps now you could put those ‘chatty’ printers into a VLAN by > themselves!) > > · With proper QoS, your phones will no longer ‘compete’ for the > wire with your PC – they’ll be given preferential treatment > > > > Disadvantages: > > · A more complicated (but well performing) network > > · More subnets to manage/account for/route > > · Really all you need is LAN QoS (proper trust boundaries and > priority queues setup in your switches) to resolve your issues here.. VLANs > **will** add complexity > > · You will have graduated from $50 switches, to $500 switches > overnight > > > > All in all, I would completely agree with your phone vendor. As it stands > right now, your phones are sharing the same media/broadcast domain as your > PCs and, thus ,‘competing’ for access to your network. VLANs are mechanism > used to thwart this competition. If you have the ability, have your vendor > reconfigure the Voice Gateway to operate in a new test VLAN… place one or > more phones into this test VLAN (on unused switchports) and test your call > quality. I think you’ll see the difference! > > > > Hope this helps! > > > > *Aaron T. Rohyans* > *Senior Network Engineer* > > *CCIE #21945, CCSP, CCNA, CQS-Firewall, CQS-IPS, CQS-VPN, ISSP, CISP, > JNCIA-ER*** > > *DPSciences Corporation > *7400 N. Shadeland Ave., Suite 245 > > Indianapolis, IN 46250 > Office: (317) 348-0099 > Fax: (317) 849-7134 > *[email protected] > *http://www.dpsciences.com/ > > *"I want an Anti-Virus system that sends Arnold back in time to kill the > hacker as a small child before he invents the virus..."* > > *"There are 10 kinds of people in this world... those who can read binary, > and those who can't"*** > > > > *From:* Evan Brastow > [mailto:[email protected]<[email protected]>] > > *Sent:* Thursday, December 17, 2009 6:40 PM > *To:* NT System Admin Issues > *Subject:* OT: VLAN question > > > > Preface: I have no idea what I’m talking about. > > > > With that out of the way, I have a network consultant and a phone supplier > that are a little bit at odds. > > > > We just purchased an Allworx IP phone system. All was going well until it > was made active today and because apparent that voice quality was horrible. > The IP part is only internal… External calls go over standard analog lines. > But the problem is with internal calls as well as external. > > > > The Allworx phones share a 100Mbps network with the computers. We’re a > small company (smaller than ever) with about 25 computers and 19 phones, > BUT, a lot of those phones and computers are out in production areas and > receive VERY little use (i.e., someone will log in/out of a job once every > few hours, and make a phone call once a day out there.) There are probably > only about 8-10 active computers, and fewer active phones. > > > > The way it’s configured is that the phone sits on the same cable as the > computer. It goes from the wall jack to the phone, and then from the phone > to the computer. The phone are on the same subnet as, and get IP addresses > from the same DHCP server as the computer network. > > > > When phone calls are made, there’s echoing, latency, static, etc… The > switch is an HP ProCurve 2810-48G. Cabling is all CAT5 at least. > > > > The phone supplier is telling me that the way to segment the traffic to > make sure there are no voice quality issues is to create a VLAN on the > switch. But my IT consultant is saying, “What’s to segment? Everything’s on > the same cable and on the same subnet?” > > > > It appears now that the phone supplier is saying that he can create a VLAN, > and then they would use the Allworx phone system server as a DHCP server for > the phones, which would put them on their own subnet, thereby making all the > traffic flow better and the calls clearer. He said he’d have to link the two > VLANS together as there are computer apps that interface with the phone > system. > > > > So, my question is (because I don’t know much about this end of > networking,) does this sound like creating a separate VLAN is really going > to help improve bandwidth and increase call quality? > > > > Thanks so much J > > > > Evan > > > > > > > > > > > > > > > > > > > > > > > > > > > ~ Finally, powerful endpoint security that ISN'T a resource hog! ~ ~ <http://www.sunbeltsoftware.com/Business/VIPRE-Enterprise/> ~
