The backbone structure of the Internet is pretty robust. Packet loss, latency, and bandwidth seldom pose a limitation for all the most time critical applications. The biggest difference among Internet access services is experienced in the last mile connection. That's the link between your router and the service provider.
Broadband connections can be divided into two major categories: shared and dedicated. Shared Internet connections include the popular DSL and Cable broadband connections. Dedicated connections are provided by T1, DS3, and Ethernet business services. Notice the term "business". Shared Internet services originated to make broadband affordable for residential and home office users. Medium to larger size businesses have always used dedicated connections for their voice and data circuits. But smaller businesses, including quick service restaurants, professional sales offices, and owner-operated shops may opt for shared connections being sold as business versions of consumer Internet services.
In the bigger picture, the entire Internet is a shared bandwidth resource. So what's the difference if your connection is shared or dedicated? The primary difference is something called "oversubscription." Oversubscription for Internet service providers is similar to overbooking for airlines. The idea is that not everyone is going to show up at the same time, even if they've paid for a ticket, or Internet service. Rather than allow those airline seats to go unfilled or that bandwidth capacity to go unused, service providers will deliberately sell more capacity than they have available. It's not really a problem until every customer really does want service at the same time.
Say your ISP (Internet Service Provider) has an OC3 backbone connection to the Internet. That a dedicated fiber optic link with 155 Mbps of capacity. Now they divvy that out to 100 customers. If they wanted to provided dedicated access, each customer would be limited to 1.5 Mbps. That way if all users were running at their maximum rate, the capacity of the OC3 connection still would not be exceeded. But chances are they'll offer each customer "up to" 10 Mbps. If only 15 customers are running their connections flat out downloading big files or video, there is still plenty of capacity for everyone. But what if all 100 want to download a video simultaneously? There's only 155 Mbps available, so each user get throttled at 1.55 Mbps.
This explains why your broadband connection seems to work faster some times and slower at others. The slow times tend to be when the most users are online and running high bandwidth applications. Even more dramatically, some ISPs might try to spread that OC3 backbone over 1,000 users, not 100. During periods of very high usage, your share of the bandwidth could be as low as 150 Kbps. Remember, the service provider is offering "up to" 10 Mbps, not any particular speed at any particular time.
As your connection speed decreases, download times increase and some applications may start to sputter. VoIP telephone calls and video feeds, including video conferencing, are particularly sensitive to bandwidth congestion. Shared bandwidth services are generally offered on a "best effort" basis, with no guarantee of performance, packet loss, latency or even availability.
With a dedicated connection, your bandwidth is set aside by the service provider and always available for your use. If you are streaming audio or video, this could be critical. Even larger grocery stores or retailers with dozens of credit card terminals need bandwidth always at the ready. In fact, any business that depends upon online access to make client presentations, manage inventory or enter orders needs a solid, dedicated Internet connection.
Dedicated Internet bandwidth and secure, private point to point connections cost less now than ever before. Don't settle for a limited service that only appears inexpensive, until you check prices on dedicated bandwidth for business locations.
