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Network Architecture. Layout designed and constructed by: Vicki Kertz. TOPOLOGIES. Bus Ring Star Hybrid Enterprise-wide WAN. Bus. a central cable that connects all devices on a local-area network. Ring.
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Network Architecture Layout designed and constructed by: Vicki Kertz
TOPOLOGIES • Bus • Ring • Star • Hybrid • Enterprise-wide • WAN
Bus • a central cable that connects all devices on a local-area network
Ring • Each node is connected to the two nearest nodes so that the entire network forms a circle.
Star • Each node (file server, workstations, and peripherals) connected directly to a central network hub or concentrator
Hybrids • Star-wired Ring • Star-wired Bus • Daisy-chained • Hierarchical
Enterprise -wide • Backbone Networks – cabling thatconnects the hubs, switches and routers • Serial – simplest; two or more connected by a single cable • Distributed – number of hubs connected to a series of central hubs in a hierarchy • Collapsed – a router or switch as the single central connection point for multiple subnetworks • Parallel – robust; more than one connection from the central router to each network segment • Mesh – routers interconnected with others and at least two pathways connecting each router
WAN • Peer-to-peer • Ring • Star • Mesh • Tiered
Network Transport Systems • The logical topology is 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.
Switching • Circuit - A type of communications in which a dedicatedchannel (or circuit) is established for the duration of a transmission. • Message – establishes a connection between two devices, transfers the info to the 2nd device, then breaks the connection. • Packet - Refers to protocols in which messages are divided into packets before they are sent. Each packet is then transmitted individually and can even follow different routes to its destination. Once all the packets forming a message arrive at the destination, they are recompiled into the original message.
CSMA/CD • Carrier Sense Multiple Access with Collision Detection • Set of rules determining how networkdevices respond when two devices attempt to use a data channel simultaneously (called a collision) • Standard Ethernet networks use CSMA/CD
Ethernet Versions • 10Base2 • 10Base5 • 10BaseT • 100BaseT • 100BaseTX • 100BaseVG • 1000BaseX
10Base2 • The 10Base-2 standard (also called Thinnet) uses 50 ohm coaxial cable (RG-58 A/U) with maximum lengths of 185 meters. • Ethernet over coaxial cable with a maximum distance of 185 meters. Also referred to as Thin Ethernet or Thinnet or Thinwire. 10Base5 • The original cabling standard for Ethernet that uses coaxial cables. The name derives from the fact that the maximum data transfer speed is 10Mbps, it uses baseband transmission, and the maximum length of cables is 500 meters.
10BaseT • 10 Mbpsbaseband 100BaseT • A networkingstandard that supports data transfer rates up to 100 Mbps (100 megabits per second). 100BASE-T is based on the older Ethernet standard. Because it is 10 times faster than Ethernet, it is often referred to as Fast Ethernet. (100BaseTX & 100BaseT4)
1000BaseT • A specification for Gigabit Ethernet over copper wire (IEEE Std. 802.3ab). The standard defines 1 Gb/s data transfer over distances of up to 100 meters using four pairs of CAT-5 balanced copper cabling and a 5-level coding scheme. • Other 1000Base-T benefits include compatibility with existing network protocols (i.e. IP, IPX, AppleTalk), existing applications, Network Operating Systems, network management platforms and applications.
Switched Ethernet • An EthernetLAN that uses switches to connect individual hosts or segments. In the case of individual hosts, the switch replaces the repeater and effectively gives the device full 10 Mbps bandwidth (or 100 Mbps for Fast Ethernet) to the rest of the network.
Ethernet Frame Types • 802.2 • 802.3 • Ethernet II • Ethernet SNAP
802.2 • General standard for the data link layer in the OSI Reference Model. The IEEE divides this layer into two sub layers -- the logical link control (LLC) layer and the media access control (MAC) layer. Destination address Length 2 bytes FCS 4 bytes Preamble 8 bytes 46 – 1500 bytes LLC Source address SSAP 1 byte DSAP 1 byte Control Field 1 byte
802.3 • Defines the MAC layer for bus networks that use CSMA/CD. This is the basis of the Ethernet standard Destination address Length 2 bytes LLC FCS 4 bytes Preamble 7 bytes 46 – 1500 bytes Source address SFC 1 byte
Mau • Multistation Access Unit • a token-ring network device that physically connects network computers in a star topology while retaining the logical ring structure • MAU is a special type of hub • One of the problems with the token-ring topology is that a single non-operating node can break the ring. The MAU solves this problem because it has the ability to short out non-operating nodes and maintain the ring structure
Design Considerations for Token Ring Networks • Cabling • Connectivity devices • # of stations • Speed • Scalability • Topology