Network and Security

Wide Area Networks Wide Area Networks can be seen as connection pipes that interconnect Local Area Networks. Usually WANs in contrast to LANs are not owned by the public; they are owned by service providers and their functionality-infrastructure is leased in order for LANs to be able to extend their expandability and make use of distant-remote services. A number of different WAN connection types exist today. Choosing the right WAN connection type is up to you, but the information in this article will make your decision process much easier. WAN Connection Types Leased Line: This is considered to be a dedicated point-to-point connection type where a permanent communication path exists between a Customer Premise Equipment (CPE) on one site and a CPE at the remote site communicating through a Data Communicating Equipment (DCE) within the providers’ site. Synchronous serial lines are used for this connection and the most frequent protocols observed in these lines are HD

The "heart" of the Internet as we know it today is the Internet Protocol (IP) which is responsible for routing data to the appropriate destination. It belongs to the group of routed protocols like IPX (Internetwork Packet Exchange), but unlike other routed protocols, the IP was designed to serve the Internet and its internetworks. In addition to IP, the Internet has various control protocols operating at the network layer (layer three of the OSI model), including: ICMP: Internet Control Message Protocol ARP: Address Resolution Protocol RARP: Reverse Address Resolution Protocol BOOTP: Bootstrap Protocol DHCP: Dynamic Host Configuration Protocol So let’s take a look at these protocols in more detail! ICMP: Internet Control Message Protocol ICMP protocol was designed with the unreliable characteristics of the IP protocol in mind. Due to the unreliability and the connectionless behavior of IP there was no way of informing the originator