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 deviceslocal-area networkdeviceslocal-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 nodehubconcentratornodehubconcentrator

Hybrids  Star-wired Ring  Star-wired Bus  Daisy-chained  Hierarchical

Enterprise -wide  Backbone Networks – cabling that connects 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 dedicated channel (or circuit) is established for the duration of a transmission. dedicatedchanneldedicatedchannel  Message – establishes a connection between two devices, transfers the info to the 2 nd 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. protocols packetsprotocols packets

CSMA/CD  Carrier Sense Multiple Access with Collision Detection  Set of rules determining how network devices respond when two devices attempt to use a data channel simultaneously (called a collision) network devicesdata channelnetwork devicesdata channel  Standard Ethernet networks use CSMA/CD Ethernet

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. coaxial cablecoaxial cable  Ethernet over coaxial cable with a maximum distance of 185 meters. Also referred to as Thin Ethernet or Thinnet or Thinwire. coaxial cablecoaxial cable 10Base5  The original cabling standard for Ethernet that uses coaxial cables. The name derives from the fact that the maximum data transfer speed is 10 Mbps, it uses baseband transmission, and the maximum length of cables is 500 meters. Ethernetcoaxial cables Mbpsbaseband transmissionEthernetcoaxial cables Mbpsbaseband transmission

10BaseT  10 Mbps baseband MbpsbasebandMbpsbaseband100BaseT  A networking standard 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) networkingstandarddata transfer ratesMbps Ethernetnetworkingstandarddata transfer ratesMbps Ethernet

1000BaseT  A specification for Gigabit Ethernet over copper wire (IEEE Std ab). 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. Ethernet  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. protocolsnetwork managementprotocolsnetwork management

Switched Ethernet  An Ethernet LAN 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. EthernetLANswitcheshostssegmentsrepeaterMbpsFast Ethernet LANswitcheshostssegmentsrepeaterMbpsFast Ethernet

Ethernet Frame Types    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. OSI Reference Modelmedia access control (MAC) layer OSI Reference Modelmedia access control (MAC) layer Preamble 8 bytes Destination address Source address Length 2 bytes LLC 46 – 1500 bytes FCS 4 bytes DSAP 1 byte SSAP 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 bus networksCSMA/CD Ethernetbus networksCSMA/CD Ethernet Preamble 7 bytes Destination address Source address 46 – 1500 bytes LLC FCS 4 bytes Length 2 bytes 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 token-ring networkstar topologytoken-ring networkstar topology  MAU is a special type of hub 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 node

Design Considerations for Token Ring Networks  Cabling  Connectivity devices  # of stations  Speed  Scalability  Topology

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