Remote Access Server
A remote access server is a computer and related software that is set up to handle users to access the network remotely. It is sometimes called a communication server; a remote access server is usually associated with a firewall server to ensure security and a router that can forward the remote access request to another part of the shared network. A remote access server can also be used as part of a virtual private network (VPN).
The Dial-up networking technology allows you to connect to your computer and other network devices to a LAN or WAN through the standard telephone lines. Dial-up networking is the simplest way and most widely used type of computer connected to the Internet. Dial-up connections are the most common type of internet connection available from ISPs; they are also the slowest and the most inexpensive.
The major types of dial-up services include V.30 and V.90 modem and also Integrated Services Digital Network (ISDN). Dial-up systems use special purpose network protocols like Point-to-Point Protocol (PPP). A dial-up Internet connection is used when a client modem calls another modem located at the Internet Service Provider (ISP). The modems transfer network information over the telephone until the modem connection disconnects.
However, the performance of dial-up networking is relatively poor due to the limitations of the modem technology. V.90 modem dial-up supports less than 56 Kbps bandwidth and ISDN handles approximately 128Kbps. The home users can replace their dial-up services with high-speed broadband technologies which operate at much higher speeds.
Features of Dial-up connection
- Dial-up networking uses a modem as the interface between a single system and a network such as the Internet; the modems are typically capable of speeds up to 56 kbps.
- A dial-up connection with a modem is the cheapest and most extensively available way to connect to the Internet, but because it offers comparatively slow connection speeds, graphics-intensive websites take a long time to download.
- The maximum speed to download the data using dial-up networking is limited by the telephone system’s analog bandwidth, the line quality, and the Internet traffic load.
- Dial-up networking usually communicates with the ISP using the Point to Point Protocol standard.
Advantages of Dial-up connection
1. Dial-up connections are very economic and are widely available,
2. Cost is affordable; same as a local phone call price, as these connections use a standard modem the hardware cost is minimal
Disadvantages of Dial-up connection
1. Dial-up connections are very slow compared to other connection types.
2. When connected to the internet the same phone line cannot be used for phone calls, if used the connected lines get a busy signal.
Dial-up connections transfer the data over an analog line so, before the data is sent it has to be converted from digital to analog, similarly when data is received it has to be converted from analog to digital, this adds a performance overhead which affects the speed of the connection.
Virtual Private Network (VPN)
A Virtual Private Network (VPN) is a network that allows the combination of computers and networks to communicate without a number of security risks. It uses the Internet or other network service as its Wide Area Network (WAN) backbone. VPN enables you to send the data between two computers across a shared or public internetwork in a method that emulates the properties of a point-to-point private link. The act of configuring and creating a virtual private network is known as virtual private networking.
A VPN allows a private intranet to be securely extended across the Internet or other network service, facilitating secure extranet connections. There are three main types of VPN:
1. Intranet VPN: It allows the private networks to be extended across the Internet or other public network service in a secure way.
2. Remote access VPN: The remote access VPN is also referred to as dial-up VPNs. It allows individual dial-up users to connect to a central site across the Internet.
3. Extranet VPN: It allows secure connections for the purpose of e-commerce. Extranet VPNs are an extension of intranet VPNs with the addition of firewalls to protect the internal network.