Routers
Multiplexers
Switches
Hubs
Gateways
Front End Processors
4. Software / Application
- Aplikasi pada nod akhir (apa yang akhir nod?) biasanya melibatkan teknik dan protokol
- Protokol menentukan peraturan dan prosedur untuk menghantar data, menamatkan data, mentafsirkan data, masa kini data dan kawalan kesilapan
- Perisian dalam fungsi rangkaian untuk memastikan data adalah dihantar ke destinasi masing- masing
- Untuk mengawal penghantaran data
5. Network Architecture Standards & Protocols
Rangka tindakan standard yang menentukan :
- Bagaimana peranti dalam rangkaian biasanya bersambung.
- Bagaimana peranti boleh berkomunikasi.
- Untuk memastikan kendalian antara pelbagai peranti dan peralatan yang dibuat oleh vendor yang berlainan.
- Untuk membolehkan peranti yang dibuat oleh syarikat yang berbeza untuk bekerja atau berkomunikasi antara satu sama lain.
Network topology is the study of the arrangement or mapping of the elements (links, nodes, etc.) of a network, especially the physical (real) and logical (virtual) interconnections between nodes.
2 Types of Network Topology :
1) Physical
2) Logical
1. Physical topology :
• The physical layout of devices on a network. or the way that the devices on a network are arranged and how they communicate with each other.
• The way that the workstations are connected to the network through the actual cables that transmit
data.
5 Types of Physical Topology :
1. Linear Bus
2. Ring / Star-wired
3. Star
4. Tree / Hybrid
5. Mesh
2. Logical topology :
• how the systems communicate across the physical topologies.
• the way that the signals act on the network media, or the way that the data passes through the
network from one device to the next without regard to the physical interconnection of the devices.
2 Types of Logical Topology :
1. Shared media topology
• In a shared media topology, all the systems have the ability to access the physical
layout whenever they need it.
• Advantage : the systems have unrestricted access to the physical media.
• Disadvantage : Collisions - If two systems send information out on the wire at the
same time, the packets collide and kill both packets. If add more systems to the
network, there is a greater opportunity for collisions.
To help reduce the number of collisions, many networks are broken up into several smaller networks with the use of switches or hubs, and each network is then referred to as its own collision
•Example: Ethernet
2. Token-based topology
• Have a token that travels around the network.
• When a system needs to send out packets, it grabs the token off of the wire,
attaches it to the packets that are sent, and sends it back out on the wire.
• As the token travels around the network, each system examines the token.
• When the packets arrive at the destination systems, those systems copy the
information off of the wire and the token continues its journey until it gets back to the
sender.
• When the sender receives the token back, it pulls the token off of the wire and
sends out a new empty token to be used by the next machine.
Advantage : Do not have the same collision problems that Ethernet-based networks
do because of the need to have possession of the token to communicate.
• Disadvantage : Latency – Because each machine has to wait until it can use the
token, there is often a delay in when communications actually occur.
• Token-based network are typically configured in physical ring topology because the
token needs to be delivered back to the originating machine for it to release.
• The ring topology best facilitates this requirement.
