Basic Router Concepts

What is a Router?

A router is a device that forwards traffic between networks based on network layer information in the data and on routing tables aintained by the router. In these routing tables, a router builds up a logical picture of the overall network by gathering and exchanging information with other routers in the network. Using this information, the router chooses the best path for forwarding network traffic. Routers vary in performance and scale, number of routing protocols supported, and types ofphysical WAN connection they support.

Routing Information Protocol

One of the protocols used by a router to build and maintain a picture of the network is the Routing Information Protocol (RIP). Using RIP, routers periodically update one another and check for changes to add to the routing table. RIP-2 supports subnet and multicast protocols. RIP is not required for most home applications. 

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Security in Network

What is IT-Security?

IT-Security is not a product, it's a process. Don't think to buy a firewall which solves all your security problems! You always have to ensure good configuration and updates - this should be an integrated process. But you never will reach 100% of security, it's like a bank safe: you can make it difficult to crack, but there will always be somebody, who is able to break it with a lot of resources! Here are the most important components of IT-Security:

Authenticity

Authenticity is about the identity of a subject/object. This can be a user, a process, a system or an information. This is needed for Non Repudiation and Accountability.

Integrity

This means Data-Integrity, that data was not manipulated or destroyed in an unauthorized way and System-Integrity, that the system is available with the usual performance and was not manipulated with unauthorized access. Integrity is part of Authenticity.

Confidentiality

Information should not been seen by unauthorized persons, instances or processes. This means protection of personnel or business-critical data, privacy and anonymity.

Availability/Dependability

Refers to functionality of soft- and hardware ist not altered in any unauthorized way and about secured business continuity.

Non Repudiation/Accountability

Non Repudiation means, that actions of instances (users, processes, systems and information) can be associated with only that instance. Accountability refers to financial transactions and all communication issues.

Reliability

The usual functionality and behavior of data and systems is secured. This is needed for Integrity and Non Repudiation.

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Inter-Network Interconnection

Which states the relationship between 2 pieces or more network devices, using a special device, namely:
Card Connector Network (Network Interface Card = NIC)
 A NIC is a printed circuit board that provides network communication capabilities to and from a personal computer on a network. 

Hub (concentrator)

Repeater

Router (Cisco-Route 2501)

 Bridge

 Gateway

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