On Wed, May 26, 2010 at 2:57 PM, helim <[email protected]> wrote: > My company's broadband is a 2Mbps fixed IP service with M1 Connect > (original contract with Qala) which costs $277 per month. Currently SingNet > has promotion for 10Mbps dynamic IP broadband which cost only $198 per > month. Since we had given-up the idea of hosting web server in-house, there > is no need to have Fixed IP broadband anymore. I checked with SingNet sales > but was advised that the 10Mbps dynamic IP broadband can only serve up to 10 > concurrent users and if exceeded, the Internet access may have problems. We > do have 18 office users but not all are accessing Internet all the time and > we also have a Computer Lab which has 12 PCs but hardly used by anyone > nowadays. I used http://www.bandwidthplace.com/ to test our Fixed IP > Internet speed which shows download speed range from 0.843Mbps to 1.016Mbps > and upload speed from 81Kbps to 226Kbps. This morning I went to another > company which is using Singnet 4Mbps dynamic IP broadband and test the speed > and was surprised to find the download speed was 4.648Mbps and upload speed > was 513Kbps! Can anyone comment or share some experience on Fixed IP and > dynamic >
Traditionally, ISPs oversubscribe their available bandwidth. ie, knowing that not everyone will attempt to fully utilise their bandwidth at the same time, they can safely sell the same 1Mbps to more than one person. In moderation, and averaged, this allows everyone to enjoy higher maximum speeds at lower cost. The extent to which they practice oversubscription is also known as contention ratio. ie, how many subscribers are contending for the same 1Mbps of bandwidth. What this could mean is that a highly oversubscribed offering might have higher theoretical burst/peak speeds but achieve lower sustained speeds when everyone else is attempting to use the network, while a non-oversubscribed or fully dedicated offering might have exactly the same burst and sustained performance. So, this can explain the sales talk that a specific plan can serve X concurrent users - if your users fit their profile of typical users and you exceed the number of concurrent users, your sustained bandwidth requirements *could* exceed their planned sustained bandwidth delivered. What's more, if everyone does so, then the true amount of bandwidth achievable by each customer would not be anywhere close to the advertised line speed, and each customer would only obtain the planned sustained bandwidth which could be much much lower, as you've observed. In practice, none of the ISPs here are willing to tell you what contention ratios they adopt, at least for consumer and lower-end business traffic. There is an expectation of lower contention ratios for business plans and for higher margin plans (eg. fixed-ip), but you never really know. So, you have no idea how much bandwidth you can realistically expect. This simplistic picture is complicated by lots of other factors, and ISPs may also take QoS or packet shaping measures to smooth bandwidth delivery. Users also typically have no idea of their own traffic profile - how much bandwidth they really need, how bursty the traffic is, etc. Short answer: bandwidth and fixed-vs-dynamic IP allocation is theoretically orthogonal. Your description of internet usage requirements suggests that network speed isn't really crucial to your business needs. If that is correct, just buy whatever you can afford (eg, a 2Mbps dynamic IP plan would likely cost less and perform similarly to your current service; 4Mbps, 10Mbps or higher might improve video streaming, but so what?).
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