On Fri, 9 Mar 2007, Zeeshan Zakaria wrote:
Hi everybody,
What is a proper setup for a medium size business with about 20 IP phones
and 20 computers. Right now they are using a regular Linksys router which we
use at homes. Their switch is also a very standard switch. Now they need to
put there something better and VoIP compatible.
What people use out there in serious and professional VoIP installations for
medium size businesses? Is there a good 24 port router with VoIP
compatibility with no need of an extra switch? Please advice me for all the
equipment I'd need for a complete network upgrade.
You'd need to supply more details for a detailled answer, (like what's the
budget ;-) and why do you think you need something better? What do you
currently have, and are they actually having problems at present, or it is
just a percieved problem?
But if this was me, and it was a "green site" installation, and money was
a bit of a consideration (it usually is IME for small businesses unless
they are new, VC funded with millions in the bank and Porsches in the car
park ;-), So I'd start with 2 decent enough 24-port Ethernet switches and
run at least 2 Ethernet lines to each desk (one for the PC, one for the
phone) back to a patch panel (actually, these days, I run 4 to each desk,
but a lot depends on the type of company!) You might want to investigate
switches with PoE capabilities - in an ideal world this would be good, but
it adds to the expense, and watch out for their power carrying ability -
some can only power 8 of 16 sockets for example - 20 phones at 6W each is
120W which is quite a bit to add to the PSU capacity of a little 1U
Ethernet switch!
Some switches can let use use 15W per port, for 8 ports, or 7.5W for 16
ports - the Grandstream phones I use claim to suck no more than 6W - is
that lucky or what ;-)
I'd steer away from using the in-line connections that many IP phones have
- unless you were desperately short of cabling capabiltiy, or money. (but
I have used the switch facilities on Grandstream GXP phones in an small
office environment where I didn't have much choice and not had any issues
with it. (Although if you reboot or unplug the phone, it takes the PC
offline!) Make sure the switch in the phone is a switch if you need to use
it! In the Grandstream Budgetone 100's it's a 10Mb HUB, not a 10/100
switch!)
Then plug all phones and the asterisk box into one switch and all PCs and
servers into the other. You can then plug each switch into the router, if
it has a switch of it's own, (a lot of the netgear ADSL routers have
built-in 4-port switches) or have a small 3rd top-level switch to connect
the 2 switches and rotuer together. or you can daisy-chain the switches
into the router if it only has one port.
So without doing anything special, this will keep VoIP traffic inside one
switch and PC/PC/Server traffic inside the other and by the switching
nature of the switches, stop traffic from PC to PC/Server interfering with
switched VoIP traffic on the other switch.
If you can't afford the luxury of separate Ethernet switches, then you
might need to look into something a bit more exotic and use Layer 2
QoS/801.p/VLan services, etc.
The above isn't perfect, but for your average small office, it's hard to
beat for a price. Things can go wrong though - someone plugging a PC into
the VoIP switch, then running network traffic intensive apps to other PCs
or servers (games, viruses). "Broadcast/APR storms" but these are rare
these days (however if you want to experiment, loopback 2 ethernet ports
and stand well back!) Some switches will detect this and suppress
excessive ARP broadcast traffic though.
Your router choice will depends on what you are trying to achieve - if you
are placing calls over the Internet, then you might want a router which
has QoS functions - however, the reality is that you can only effectively
use QoS when you control every aspect of the link - which with most ISPs
you can't. (And you don't say if you have an ADSL, Cable, Leased line,
etc. connection - not that it matters that much, however) Most routers
will make a good effort though, but over the big bad Internet (and
incoming data to your site in particular) you have no control over.
Saying that, with a good ISP and reasonable staff, most of the time you
"get away" with it, and I regularly chat with my clients and friends over
the 'net even when I know some of them have no QoS at all on their company
routers. One site in particular has 100 staff, a 4Mb Internet line and I
regularly make calls over their non QoS'd Internet line to other sites
without any issues at all. (But it just takes one person running some
agressive P2P software to kill it for everyone!)
If you are running VPNs to other sites, make sure the router is up to it!
After many years of using Drayteks, I now find them a PITA as they can
only sustain about 1.5Mb/sec through an encrypted VPN and with todays 8Mb+
ADSL lines and 10Mb WAN connections, makes them less useful than they once
were )-:
If you are not placing calls over the internet, and it's purely internal
only, then your choice of router isn't really that important, as long as
it can handle your NAT, firewall, etc. requirements.
Gordon
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