I would have to say "It Depends".
The first question you should ask is "how is the Internet bandwidth going to be used?" Suppose your company has one really big client, and that your company hosted a web site that provided application services for that client. internet safety that case, you would probably want to use the same ISP (likely a Tier 1) that your client uses. In most cases, you will provide the fastest (in terms of Internet router hops) from your client's PCs to your company's mega web site through the Internet Provider's own IP network -- because your client's packets do not have to traverse any public peering points (NAPs). (I only offer up this unlikely example to illustrate a point)
Another more likely scenario is that your company has multiple remote sites that it wants to connect via VPN. In the ideal world, you would want each remote site to install Internet access from the same ISP. This is again so that the number of router hops between the remote sites and your headquarters site through the Internet is minimized, peering point traversals are eliminated, and latency is minimized. If the remote sites are distributed throughout the US, you might need to consider a Tier 1 ISP in order to provide service to all of your remotes. If on the other hand, your remote sites are regional, a strong Tier 2 regional ISP may offer better connectivity, lower prices, and better peering streamyx combo goes other regional ISPs.
Of course, another major consideration is the flexibility of the ISP to offer last-mile connectivity options. Can the ISP grow with you? You might start with a single T1 Internet connection, that Broadband Tv to two or three T1s in a PPP multilink. Where can the ISP take you from there? Is a fiber-optic link into 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 company from the ISP's Point of Presence (POP)? Does the ISP have access to fiber in your area, or would it have to be installed?
Hopefully, I have begun to make a case that bandwidth and price are not the only things to consider when choosing an ISP.
Note that unless you are using MPLS connectivity to other company sites through this Internet connection, QoS really doesn't come into play. An SLA on the other hand, is always a good thing to have -- especially if you are running mission-critical applications for your company (or a client of your company). It is probably not a bad idea to check out the ISP's financial health as well.
All that said ... here's a simplistic justification for selecting a Tier 1.
Tthe simple answer is that the Tier 1 providers privately pier with each other and expand their connections as needed to support their customers and the Internet traffic that they transfer to each other. Tier 2 and below have to purchase bandwidth from Tier 1 providers to move traffic to and from the major internet backbone providers which the Tier 1's represent.
Essentially, the fewer hops you have and potential bottlenecks, the better the providers solution is to your world and the more extensive the backbone and resulting connections to all Internet providers, the better the communication and performance you can expect.
Now of course .... is that what your business "needs" to operate?
Tier-2 providers can provide good service, but if you're setting up a multi-site WAN and all of your sites are within the same Tier-1's service area, its hard to see how you'd be able to get more reliable service than a mesh provided by that Tier 1. All outages would be handled by one vendor ... That really is the big downfall of the tier-2 providers: streamyx hotspot prepaid packets are riding somebody else's glass or copper for the last-mile of the trip. Which is coincidentally where 90+% of the problems with a MPLS setup tend to crop-up ... between the neighborhood CO and the CPE internet quiz the sites.
The bottom line .... a lot depends on what sort of service you want and where.
To help you walk through making any decision on a bandwidth solution ... I suggest taking advantage of the no cost assistance available at DS3-Bandwidth.com.
Michael is the owner of FreedomFire Communications....including DS3-Bandwidth.com. Michael also authors Broadband Nation where you're always welcome to drop in and catch up on the latest BroadBand news, tips, insights, and ramblings for the masses.
