Sunday, April 25, 2010

Introduction to Network Concepts I

CCNA networkingIn this post I'm going to talk about important concepts of networking that really help you to do CCNA with great knowledge.also in this section I'm describing extra things that not in CCNA syllabus but these basic concepts are help you to get clear idea about networking.
A computer network is a group of computers. Network may be classified according to a wide variety of characteristics.
First Computer Network:-The Advanced Research Projects Agency (ARPA)designed "Advanced Research Projects Agency Network"(ARPANET) for United states Department of Defence as first Network during the Cold war in December 5,1969.

Network Classification
1.Using Connection method.

In this, we can classify Network according to the hardware and software technology that is used to interconnect the individual devicesin the Network. such as Optical fiber,Ethernet,Wireless LAN,HomePNA,Power line communication.

Ethernet use physical wiring to connect devices. frequently deployed devices include Hubs,Switches, Bridges, or Routers.
Wireless LAN technology is designed to connect devices use Radiowaves or infrared signales as transmission.

2.Using Scale
Network also classified according to their Scale as
  • Local Area Network (LAN)
  • Wide Area Network (WAN)
  • Metropolitan Area Network(MAN)
  • Personal Area Network(PAN)
  • Virtual Private Network Area Network (VPN)
  • Campus Area Network CAN)
  • Storage Area Network (SAN)

These classification depending on their Scale I'm going to describe these things deeply in later Posts but here you want to get clear idea about differences between LAN and WAN.In short and sweet we can say "You own the LAN and You hire the WAN" this mean if we get LAN it spread over same geographical area and all the stuff in network belongs to that organization. it may be one building ,several building, campus or one small island.WAN exists over many office buildings separated by a vast distance the office buildings in a WAN may be in different countries or even continents. important thing is WAN not belongs to organization it may use some third party services like ISP services. The other difference between LAN and WAN, is the speed of the network. The maximum speed of a LAN that most likely to be based on switched IEEE 802.3 Ethernet, or on Wi-Fi technology can be 1000 megabits per second, while the speed of a WAN can go up to 150 megabits per second. This means the speed of a WAN, is one-tenth of the speed of a LAN. A WAN is usually slower because it has lower bandwidth.

3.Functional relationship (Network architecture)

also network can classify according to functional relationship which exist among the elements of the network. Active Network, Client-sever Network, Peer to Peer(e.g.torrent)

4.Network topology

Network topology signifies the way in which devices in the network see their logical relations to one another.
According to Network topology we can classify Network as Bus Network, Star Network,Ring Network, Mesh Network, Star-bus Network, tree or hierarchical Network

Cisco standard symbols in networking ,ccnaLet's get some brief idea about some important devices in network
  1. Router ,ccna ,ccnaRouter used to forward data among computer networks beyond directly connect devices so routers route packets of abstracts from one arrangement to another.Routers are most commonly related to Network layer of the OSI model (layer 3 ), but arguably also operate on Data Link (layers 2)

2. Switch ,ccna ,ccna
Manage network connection between any pair of star wired devices on a network so Switches add more intelligences to data transfer management than hub.also Switches work at Data link layer(layer 2) of OSI model.

3. Hub ,ccna ,ccna
Pass electronic signals to the network and connect group of host together. Repeater hubs also participate in collision detection, forwarding a jam signal to all ports if it detects a collision.In OSI model hub work at physical layer (layer 1).

4. Bridge ,ccna ,ccna
A bridge device filters data traffic at a network boundary. Bridges reduce the amount of traffic on a LAN by dividing it into two segments. also bridges working at the Data link layer (Layer 2) of OSI model.

5. Network interface card ,ccna ,ccnaA network interface card is used to connect a computer to an Ethernet network. The card provides an interface to the media.The card usually also contains the protocol control firmware and Ethernet Controller needed to support the Medium Access Control (MAC) data link protocol used by Ethernet. NIC work at Physical(Layer 1) and Data link(Layer 2) Layers of OSI model.
Next post I will talk more about these important concepts in networking thanks for reading.

Friday, April 23, 2010

Overview of Cisco and CCNA

CCNA is a professional level certification in Cisco certifications.professional level means these certifications designation earned by a person to assure qualification to perform a job or task. so these Cisco certification are created for give expert knowledge about Cisco products, mainly Cisco routers and Switches. so briefly following things we are going to learn under CCNA tutorials from here.
Cisco Certified Network Associate (CCNA) validates the ability to install, configure, operate, and troubleshoot medium-size route and switched networks, including implementation and verification of connections to remote sites in a WAN. CCNA curriculum includes basic mitigation of security threats, introduction to wireless networking concepts and terminology, and performance-based skills. This new curriculum also includes (but is not limited to) the use of these protocols: IP, Enhanced Interior Gateway Routing Protocol (EIGRP), Serial Line Interface Protocol Frame Relay, Routing Information Protocol Version 2 (RIPv2),VLANs, Ethernet, access control lists (ACLs)

Ok lets talk little bit about job opportunities for CCNA when we talk about this truth is along with CCNA we have nothing. All you need is ability to do some thing just it. using CCNA you can start your network career and you can make beautiful it. SO I think that CCNA is important as a door opener,also CCNA is a prerequisite to CCNP as well-as a lot of recruitment agencies won't even consider you regardless of how much experience you have if you don't have CCNA/CCNP that recognition have it.Following are some links you can find about job opportunities and about average salaries offered in IT jobs that have cited CCNA.

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