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Network Security with T1 Firewall Routers

written by: Bruce Tyson•edited by: M.S. Smith•updated: 4/21/2010

Business and individuals that require a lot of bandwidth for voice and data communications are increasingly turning to T1 services. With the additional capacity of a T1 and the security of a T1 firewall router, your business will have the connectivity and security it needs.

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    T1 Overview


    A T-carrier line, or T1, is a data connection with capacity exceeding that of normal phone lines and broadband. T1 connections are wired or optical pipes that have a data throughput that is superior to broadband Internet connections in both speed and reliability, making them the preferred choice for businesses that have critical data needs. A T1 can transmit 1.544 megabits per second of data or it can be segmented into 24 channels carrying digitized voice signals. The speed of a T1 is guaranteed by the carrier, meaning that outages and other deficiencies in service can result in service credits. Although T1 service is not cheap, prices have come down in recent years, making the service a viable option for businesses with numerous CO lines and/or heavy data requirements.

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    T1 Routers

    T1 routers differ from a normal network router because it has circuitry built into it that interfaces the network to the T1 connection. Without that circuitry, an external CSU/DSU is needed to interface the T1 with a traditional router for network productivity. Because of their critical nature and “always on” nature of the connection, T1 routers are highly engineered products that are designed to run a very long time without crashing or cycling power.

    Unlike consumer-grade broadband routers that are often plug and play, most T1 routers require a great deal of programming to detail how different types of inbound and outbound traffic are managed. Also, T1 routers are typically quite expensive when compared to the broadband routers that consumers and small businesses use. This is largely due to their quality and reliability requirements as well as the additional circuitry required for the T1 interface. Configured properly, T1 routers direct network and Internet traffic to insure the integrity of mission critical services.

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    Network firewalls are designed to restrict unauthorized access to a local area network. Their purpose is to keep out malicious attackers, safeguarding legitimate network traffic. The firewall functions by examining every packet and the credentials and identification that is associated with it. Although many consumers use software firewalls installed on their computers, businesses generally favor hardware firewalls that stand between the incoming data connection and the rest of the network.

    The firewall of a T1 firewall router is not like the automatically configured firewalls that come in consumer-grade products. These are usually firewalls which implement context based access control to secure the network. For example, if traffic is allowed to go outside the network, the firewall will usually allow return traffic if it matches the state information associated with the outbound request. Configuration requires knowledge of the router’s programming language to choose how UDP, TCP, FTP, SMTP, and other protocols are handled. Many Cisco routers that include the firewall feature set of the Cisco IOS are examples of routers with integrated firewalls. This feature set comes equipped with pre-built access control lists (ACL) that define default ports for different types of traffic, giving administrators a head start in creating the firewall configuration.

    When configured properly, the firewall will filter and inspect traffic, produce real time alert notifications and an audit trail, and detect intrusions based on lookups against the most common signatures of attacks.

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    Advantages of T1 Firewall Routers

    By combining a T1 interface and a built-in firewall, T1 firewall routers are ideal solutions for implementing and securing a network. They conserve space, make the most of administrative time, improve the reliability of the network and save cost all at once.