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T1s can be used for point-to-point services or for access services, and both applications can terminate directly into a router, which some may call a T1 router. These so-called T1 routers provide a critical service to the T1 system. Router Basics. Routing is the management of information across a network and involves two primary functions: 1) Establishing logical destination paths for information to use, and 2) Transmission of information "packets" along the predetermined routes. Routing tables can be either discovered or programmed, depending upon the complexity of a network. In a fully meshed network, several route choices may exist for transmission between two points. Private Line Data Applications. Data applications are the most common for private line services. Generally, these link two Local Area Networks together, and the private line link is considered the WAN (wide area network). Since T1s can be provisioned linking locations across the street or across the country, there's no theoretical limit to the distance. Only data application sensitivity may dictate that latency be no greater than a designed limit. Latency is a measure of how long it takes to send a packet from one location to another, and return a response. Also known as round-trip delay, data applications will typically accommodate a point-to-point T1, no matter the distance. When considering migrating from this service to either a Frame Relay or pure IP environment, much closer attention must be paid to applications and the effects of latency. Frame Relay or IP Applications. Since the late 90's more businesses have migrated their private networks to packet or frame-based networks, saving the long-haul telecom charges for a fully meshed network. In the case of frame relay, each location would have an access T1 for frame relay, and PVCs (permanent virtual circuits) would allow interconnection between two points through the frame relay network. While each PVC has a charge, and each must have a CIR (committed information rate), businesses found that the flexibility of virtual network could not only save them money, but they could reconfigure their network in much less time, using much less hardware. IP services became mainstream in 2001, with the popularity of the Internet taking hold for business applications. While security of IP-based networks remains the main concern, a properly designed IP VPN (virtual private network) is the most flexible. In an IP network, firewalls and intrusion detection appliances are a must to keep valuable company data private. |
T1 Routers
