I would have to say “It depends”.
The first question to ask yourself is “how will the Internet bandwidth be used?” Suppose your company has a really big customer, and your company hosts a website that provides application services for that customer. In that case, you’ll probably want to use the same ISP (probably a Tier 1) that your customer uses. In most cases, it will provide the fastest (in terms of internet router hops) from your customer’s PCs to your company’s mega website over the internet provider’s own IP network, because packets from your client do not have to traverse any public interconnection point (NAP). (I’m only offering this unlikely example to illustrate a point)
Another more likely scenario is that your company has multiple remote sites that you want to connect via VPN. In the ideal world, you would want each remote site to set up Internet access from the same ISP. This is again so that the number of router hops between the remote sites and the headquarters site over the Internet is minimized, peer-to-peer crossings are eliminated, and latency is minimized. If your remote sites are spread across the US, you may need to consider a Tier 1 ISP to service all your remotes. If, on the other hand, your remote sites are regional, a strong regional Tier 2 ISP may offer better connectivity, lower prices, and better interconnection with other regional ISPs.
Of course, another important consideration is the ISP’s flexibility in offering last-mile connectivity options. Can the ISP grow with you? You can start with a single T1 Internet connection, which grows to two or three T1s on a PPP multilink. Where can the ISP take you from there? Is a fiber optic link in your building (to support a DS3 or OC3 or packet over SONET) an option? Is redundant connectivity with diversely routed fiber an option? How far is your business from the ISP’s Point of Presence (POP)? Does the ISP have access to fiber in your area or would I have to install it?
Hopefully, I’ve started to make the case that bandwidth and price aren’t the only things to consider when choosing an ISP.
Note that unless you’re using MPLS connectivity to other company sites over this Internet connection, QoS doesn’t really come into play. On the other hand, it’s always good to have an SLA, especially if you’re running mission-critical applications for your business (or a customer of your business). It’s probably not a bad idea to also check the financial health of the ISP.
All that being said… here’s a simplistic rationale for selecting a Tier 1.
The simple answer is that Tier 1 providers connect to each other privately and extend their connections as needed to support their customers and the Internet traffic that they transfer to each other. Tier 2s and below have to buy bandwidth from Tier 1 providers to move traffic to and from the major Internet backbone providers that represent Tier 1s.
Essentially, the fewer hops and potential bottlenecks you have, the better the provider’s solution will be for your world, and the more extensive the backbone and resulting connections to all Internet providers, the better communication and performance you can expect. .
Now of course… is that what your business “needs” to function?
Tier 2 providers can provide good service, but if you’re setting up a multi-site WAN and all your sites are within the service area of the same tier 1, it’s hard to see how you could become more reliable. service than a mesh provided by that Tier 1. All outages would be handled by one provider… That’s really the big downfall of Tier 2 providers: Your packages are using someone else’s glass or copper for the last mile From the trip. Coincidentally, that’s where over 90% of the problems with an MPLS setup tend to arise… between the neighborhood CO and the CPE at the sites.
The end result… a lot depends on the type of service you want and where.
To help you make any decision about a bandwidth solution… I suggest you take advantage of the free support available at DS3-Bandwidth.com.