asterisk users - Dec 2004 - Is Gigabit Ethernet necessary?

For an office that is using VoIP phones to connect to Asterisk, is gigabit 
ethernet really necessary for the Asterisk box to connect to the switch? I 
know that I won't even approach the limits of 100 Mbps, but would gigabit 
help with latency / collisions when several calls are underway? The fact 
is, anything going outside the office will be over a data T1, so intuition 
tells me that 100 Mbps should be fine...  The office will have 20 phones, 
with remote VoIP phones added to the mix later on.

TIA,
-Ron
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rsenykoff@harrislogic.com wrote:
> For an office that is using VoIP phones to connect to Asterisk, is gigabit 
> ethernet really necessary for the Asterisk box to connect to the switch? I 
> know that I won't even approach the limits of 100 Mbps, but would
gigabit
> help with latency / collisions when several calls are underway? The fact 
> is, anything going outside the office will be over a data T1, so intuition 
> tells me that 100 Mbps should be fine...  The office will have 20 phones, 
> with remote VoIP phones added to the mix later on.
If you are using a switch, collisions a pretty much a non-issue, unless 
you have enough traffic to saturate a port to the server. Latency is 
also not helped any significant amount, since you still have a 100Mbit 
link in the path between the phone and Asterisk.

In other words, for that application, it likely will not make any 
difference at all. If it's cheap to do, and the server will also be 
doing any file serving duties, then it would be a nice insurance policy 
against a single user swamping the server's port.

rsenykoff@harrislogic.com wrote:
>
>  For an office that is using VoIP phones to connect to Asterisk, is
>  gigabit ethernet really necessary for the Asterisk box to connect to
>  the switch? I know that I won't even approach the limits of 100 Mbps,
>  but would gigabit help with latency / collisions when several calls
>  are underway? The fact is, anything going outside the office will be
>  over a data T1, so intuition tells me that 100 Mbps should be fine...
>  The office will have 20 phones, with remote VoIP phones added to the
>  mix later on.
http://www.voip-calculator.com/calculator/lipb/

Don't forget that you can't send 100 Mbps through a 100Mbps link.
>  TIA,
TR41, probably.

Nick

rsenykoff@harrislogic.com wrote:
> 
> For an office that is using VoIP phones to connect to Asterisk, is 
> gigabit ethernet really necessary for the Asterisk box to connect to the 
> switch? I know that I won't even approach the limits of 100 Mbps, but 
> would gigabit help with latency / collisions when several calls are 
> underway? The fact is, anything going outside the office will be over a 
> data T1, so intuition tells me that 100 Mbps should be fine...  The 
> office will have 20 phones, with remote VoIP phones added to the mix 
> later on.
> 
> TIA,
> -Ron
> 
Ron,

	For what it costs, it is usually worth it to put a gig card in your 
server (a good one).  Gigabit cards have newer and much better buffering 
and pci bus support.  They are also much better at offloading processing 
from the system's CPU.  You need to make sure that you have a good one. 
  Because a crappy Gigabit card is probably not much better than a 
crappy 100mb card...

	I like Intel nics (both 100mb and 1000mb).  Something supported by 
e1000 shouldn't be too expensive and usually will work pretty well with 
most all OS's.

my $0.02

--
Kristian Kielhofner

rsenykoff@harrislogic.com wrote:
> 
> For an office that is using VoIP phones to connect to Asterisk, is 
> gigabit ethernet really necessary for the Asterisk box to connect to the 
> switch? I know that I won't even approach the limits of 100 Mbps, but 
> would gigabit help with latency / collisions when several calls are 
> underway? The fact is, anything going outside the office will be over a 
> data T1, so intuition tells me that 100 Mbps should be fine...  The 
> office will have 20 phones, with remote VoIP phones added to the mix 
> later on.
The reason to chose a Gigabit Ethernet card has nothing to do with 
bandwidth - (most of?) these card use some sort of interrupt mitigation 
technique which takes a hell lot of load off of the processor for 
dealing with interrupts.

VoIP traffic, with it's typical many small packets, is very susceptible 
to causing interrupt live lock on servers and routers and interrupt 
mitigation scheme (or even polling, but that's rare) makes a real change 
in performance.

Having said that, there are 100Mb cards that do interrupt mitigation as 
well (for example AFAIK the Intel e100 cards) and there are drivers that 
implement interrupt mitigation at the software level (customized drivers 
for the tulip chip set based cards and the Linux NAPI framework).

However, it is simply much easier to just grab a Giga card then research 
which 100Mb chip and which driver you need to get ;-)

Hope this helps,
Gilad

-- 
Gilad Ben-Yossef <gilad@codefidence.com>
Codefidence. A name you can trust(tm)
Web: http://codefidence.com  | SIP: gilad@pbx.codefidence.com
Tel: +972.9.8650475 ext. 201 | Fax:  +972.9.8850643

"I am Jack's Overwritten Stack Pointer"
	-- Hackers Club, the movie

rsenykoff@harrislogic.com wrote:
> 
> For an office that is using VoIP phones to connect to Asterisk, is 
> gigabit ethernet really necessary for the Asterisk box to connect to the 
> switch? I know that I won't even approach the limits of 100 Mbps, but 
> would gigabit help with latency / collisions when several calls are 
> underway? The fact is, anything going outside the office will be over a 
> data T1, so intuition tells me that 100 Mbps should be fine...  The 
> office will have 20 phones, with remote VoIP phones added to the mix 
> later on.
> 
> TIA,
> -Ron
> 
Ron,

For what it costs, it is usually worth it to put a gig card in your
server (a good one).  Gigabit cards have newer and much better buffering
and pci bus support.  They are also much better at offloading processing
from the system's CPU.  You need to make sure that you have a good one.
  Because a crappy Gigabit card is probably not much better than a
crappy 100mb card...

I like Intel nics (both 100mb and 1000mb).  Something supported by
e1000 shouldn't be too expensive and usually will work pretty well with
most all OS's.

my $0.02

--
Kristian Kielhofner