Internet Series #1: Overview
Updated: Oct 31, 2019
There are many factors to consider when choosing an Internet Service Provider (ISP). It’s not always about who has the lowest cost or largest inventory of IP routes. Connectivity, traffic flow, and network congestion are a few key factors that I mention below.
Looking on asrank.caida.org, you will see that the undisputed ISP champion is CenturyLink, who purchased Level 3. There is no other provider close to the size of CenturyLink Autonomous System (AS) IP routes, which means that CenturyLink has the most routing prefixes to the internet. However, just because you have the largest amount of routing prefixes to the internet does not mean you have the most robust overall network. For instance, Zayo was one of the first to provide 100 Gbps access to the internet.
The medium of connectivity to end points/offices can make a difference in how stable internet service can be. Internet was originally provided over copper pairs (T1, NxT1, DS3, OC3, OC48, OC192), but keep in mind that copper pairs were never invented to transmit internet data services, they were developed for voice services. These mediums ended up creating stability, efficiency, and packet loss issues, as well as limitation of overall speeds. Ethernet over Copper, or EoC, is an interesting way to combining copper pairs into a single connection rather than running MLPPP to bond T1’s (NxT1). Currently, the most efficient way to deliver bandwidth is over native Ethernet, fiber or microwave.
Internet traffic is a very intertwined business. Traffic flows over multiple networks through multiple peering points (where the internet providers hand off traffic between ISP networks) to reach its’ destination. For example, if Amazon uses AT&T and your office uses Verizon for their internet access, in order to get to Amazon’s services, your internet request needs to traverse from Verizon to AT&T. That hand-off between providers is called peering and only takes place at certain peering points throughout the US and world. The is extremely important when using VPN, SIP, UCaaS/CCaaS or any latency sensitive traffic.
Some ISPs will grossly over oversubscribe their network making network congestion an issue creating packet losses and re-transmission of packets an issue. They do this to increase profitability Vs building out additional capacity. There are also features that make some ISPs more attractive than others. These include network-based firewalls and DDoS capabilities, prioritization of IP traffic and privatized WAN traffic.
In closing, when choosing an ISP it is important to consider the factors listed above. Stay tuned for the next blog in our Internet series...