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A common question for network connectivity is "how much bandwidth is enough?" While bandwidth can boil down to upload and download limits from an ISP, the overall question is really one of network speed - how fast is the network connection to the Internet? Network speed is greatly influenced by the routing methods used to direct network traffic; the better the traffic routing, the better the network connection's speed and reliability.

Routing Traffic: BGP

The Internet is made up of millions of individual servers, which are all interconnected, like houses on main streets and bystreets. Some central networks, called backbones, have connections to millions of servers, which makes it easier to send traffic along those routes.

If an ISP is connected to a single Internet backbone, then they only have one route to use to send traffic. However, this means if that backbone goes down, the network connection goes down. For redundancy, most ISPs have connections to at least two backbones, and traffic is routed between those backbones.

When there are multiple backbones to choose from, there has to be some way to identify the most efficient route. The most common routing logic is border gateway protocol (BGP) which counts the number of networks (autonomous system, or AS, hops) that each route has between the starting server and the destination server.

For example, one person wants to send an email from their home account with SBC Global to their friend at MSN. SBC is on one network, and MSN is on another. Route A reports six AS hops between SBC and MSN, and Route B has three AS hops between them. With BGP routing, the traffic is sent on Route B.

Performance-Based Routing

The big limitation of BGP is that it only gauges AS hops rather than other more important factors, like latency. Route B from the last example has only three AS hops, meaning traffic only has to cross three networks to reach its destination. However, BGP routing only counts AS hops - it cannot account for the number of individual routers in an autonomous system. Route B may only cross three networks, but if Network 1 has five routers, Network 2 has four routers, and Network 3 has eight routers, the traffic has to go through 17 routers before it can reach its destination. If Route A crosses six networks but each network only has a single router, the traffic only has to pass through six routers. That means that Route A may be significantly faster than Route B, but BGP routing has no way to recognize that, so it sends traffic down the slower route.

Performance-based routing offsets the limits of BGP, and takes a more intelligent approach to traffic routing, by looking at other factors than AS hops:

?Performance metrics like latency, jitter, and packet loss
?Current network load
?Connection type, such as T1 or OC3

Latency can be either the time to send a packet one-way or the round-trip time, like the time to send ICMP packets (ping) to one server and receive the response. Jitter is the fluctuation in latency times. For example, if the first trip time is 3ms and the next is 105ms and the next is 20ms, there is a large swing between trip times, and, therefore, there is high jitter on the connection. Packet loss is the number of packets (information) which never reach their destination. The current load is how much traffic is currently on that connection, and the connection type indicates how much traffic the network can handle effectively.

By looking at the actual quality of the network connection, performance-based routing can select much faster, more reliable routes.

What Better Routing Really Means

Poor routing can corrupt or interrupt packets, requiring information to be resent and increasing the overall time it takes to do anything on the network. While simple tasks like web browsing may not be affected by poor network performance, a number of vital applications can be impaired by poor routing protocols in ways that may not be apparent in a simple upload/download size summary:

?Any kind of media application, such as streaming video or audio
?Potentially business-critical applications like voice over IP (VoIP) or video conferencing
?Upload and download times
?Email delivery
?Remote network applications like VPNs

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A T3 is a dedicated high-speed line that can be used for voice or data. The T3 uses digital signal and is transmitted over fiber or copper. It transmits data at a high speed - 43.232 Mbps. This speed is greater than most modems.

A T3 is equivalent to 28 T1s. Each T1 is made up of 24 channels that can be used for voice or data. The T1 terminates into the telephone room on a jack called a smart jack. From there you can extend the circuit into the telephone or data equipment with a simple fiber cable. Each T1 uses 2 pair fiber connections to bring all channels to you. Therefore, the space requirements for T1 lines are much less than the equivalent amount of standard copper trunks would take up.

Each T1 provides 24 channels, which are then shared among the users. The T1 works efficiently to provide flexible channels as needed. When a channel is free it is available to any user. The typical T1 can accommodate between 50 and 100 users comfortably. More phone-intense applications such as call centers will require additional T1s. If you have significant need, a T3 is the next logical choice. It provides an extended bandwidth that will easily accommodate all applications.

Many people are familiar with a DSL or digital subscriber line. The DSL is a slower circuit, which is not dedicated. It typically runs over your current telephone line and is mainly used for individual service. The T1 circuit is a dedicated circuit used specifically by businesses. The speed of the T1 is much faster than the DSL allowing for more advanced features and connections. The DSL is not a viable option for a large company or organization. Instead, a T1 is the preferred telecommunication method for businesses.

Larger organizations such as those with a campus environment may need more than one T1. For these situations there is the T3. It can be used for voice, data or both, depending on how it is configured. To determine your needs you should first determine your current usage for both voice communications as well as data communications. Next, be sure to understand what data applications you currently use as well as those that your company would like to use given the proper bandwidth. Then, think about future growth, not only specific growth of the company but also the growth of applications that may become available in the future.

A T3 may seem expensive however it is always a less expensive choice than using a comparable amount of typical standard copper trunks. The costs of T1s and T3s have actually been decreasing in the past several years. This is due in part to the fact that most central office locations are now upgraded to be able to supply these services. Another factor is that there is now much competition with many providers offering these services. Installation costs may be steep but you should expect to see a good return on your investment easily within a year.

Article written by Van Theodorou, for a free consultation to see if you need a T3 voice or internet service and learn more on the T3 at his T3 learning center.