bandwidth usage calculator

Hi Guys,
we have a 512 Kbps link from India to UK, the link is 98% loaded all
the time, we have to calculate a optimal B/W so that there is no
network clogging, are there any thumb-rules for calculating the
bandwidth??

Regards,
Sai.

 

Well, it's hard to do that just like that.. It would be best if you could
measure traffic comming to your router's ethernet and than you could see how
much traffic are you consuming. Then you will see how much do you really
need. If that is too much, use traffic shaping/policing on "unimportant"
traffic.

Ivan

 

Hi Ivan,
I was wondering if i use the rule 60% LAN and 40% WAN traffic is the
optimal traffic to avoid bottlenecks, since my network B/W utilization
is aroung 98%, means 58% more is used (causing clogging), is this
making any sense to you and does this sound logical??????

Sai.

 

Well, yeah if your WAN is really 98% utilized. But, it might be a 100%
utilized and showing only 98% (when you have congestion, you won't use all
bandwidth). So, if you double your WAN bandwidth you could get 98%
utilization again and you will not solve your problem.

Ivan

 

Hi,
So according there is no way to roughly estimate the bandwidth needed
for my setup???
whatever calculations i am making is keeping in mind that anything
above say 40%(not mandatory) on my WAN is CONGESTION for me.
u r absolutely correct in saying that since i have only 512 kbps, the
utlization is showing 98% since there is no room for expansion, so i
prescribe 1Mb link, so that the utilization might be roughly 768 Kbps
and I still have 256 Kbps, i.e 1/4 of the bandidth left for any more
bursty load.
any suggestions????

Sai...

 

No - or probably not.

Most traffic flows try to adapt to the available bandwidth and congestion
(or in some cases delay).

In this case everything will be throttling back due to the discards and
latency the congestion intorduces.

Much better to put a sniffer on there and see what is using the bandwidth
than just blindly increase it and hoping that it sorts the problem. Or look
at load when the network is at low load, or as the number of users varies.

You may find you need more bandwidth, but often this sort of level of
congestion is down to misconfiguration (ie. use a remote mail server instead
of local), or you need to think about changing the network setup 1st.

Once you have that then yes - designing for around 50% load in the busy hour
is a good place to start - but you cant do that until you understand what is
supposed to go across the link, or you have some sort of baseline.