2.  Describe the basic and hybrid LAN physical topologies and their uses, advantages, and disadvantages  Describe the backbone structures that form the foundation for most LANs  Understand the transmission methods underlying Ethernet networks  Compare the different types of switching used in data transmission

3.  Is the physical layout of the nodes on the network  3 fundamental shapes  Bus  Ring  Star

4.  Also known as the passive topology  Supports only one channel  All nodes must listen before transmitting  Uses coax cable that must be terminated with 50-ohm resistors to prevent single bounce – never ending transmissions  Does not scale well

5.  Each node is connected to the two nearest nodes forming a circle  Data travels in a clock wise motion around the ring  Each node accepts and responds to packets that are addressed to that node.  Provides a single point of failure for the entire network

6.  Most commonly used topology  Every node connects to either a central hub, router or switch  Can only support 1024 nodes

7.  Refers to the way the data is transmitted between nodes rather than the physical layout  Most common are bus and ring topologies  Knowledge of logical topologies aid in troubleshooting

8. Star-wired ring Star-wired bus

9.  Cabling that connects the hubs, switches and routers  Uses mediums that are high capacity capable  Carries more traffic than local nodes  The most significant piece in the network’s infrastructure

10.  Simplest type  Connects in a daisy-chain fashion  Gateways, routers switches and bridges are the most common devices that are found in this type of backbone

11. ◦ Network devices are connected in a hierarchy ◦ The order of the hierarchy is as follows  Routers  Switches  Hubs ◦ Allows for simple growth and limited capital outlay for growth ◦ To expand, just add more layers ◦ Provides the ability to segregate workgroups ◦ More easily managed

12.  Collapsed Backbone ( Needs Graphic) ◦ Uses only one router or a switch for all connections to the networks nodes ◦ Risky because of a central point of failure  Parallel Backbone ( Needs Graphic) ◦ Most robust type of backbone ◦ Provides 2 central routers with 2 connections to every switch

13. ◦ Determines how connections are made between nodes ◦ Three methods of switching  Circuit switching  Message switching  Packet switching

14.  Circuit Switching ◦ Connection is established before data is transmitted  Stays connected until users terminate the session  Bandwidth is dedicated to this connection  All data flows down the same path ◦ Suited for voice and video transmission  Message Switching ◦ Once the connection is established it forwards the data ◦ Once the data is forwarded the connection is broken down  Packet Switching ◦ Most popular method ◦ Packets are down any path in the network to its final destination ◦ Once the packets reach their destination, the packets are reassembled

15. ◦ Integrates Layer 2 information about network links (bandwidth, latency, utilization) into Layer 3 (IP) within a particular autonomous system in order to simplify and improve IP-packet exchange.IPpacket ◦ Can create circuit switched like connections ◦ Uses MPLS labels to improve operation  MPLS label is inserted between layer 2 header and layer 3 header  Routers only need to interpret the MPLS label then forward the packet ◦ Provides better QoS due to faster packet forwarding

17.  All Ethernet networks use CSMA/CD  Carrier Sense Multiple Access  The node must first access the transmission medium and “listen” to see if the channel is free  If it is not clear to transmit the node waits a brief time and then retries  Collision Detection  Once a node has detected a collision it stops transmitting  The node’s NIC issues a 32-bit sequence that alerts the rest of the network nodes that the collision has taken place - called jamming  This lets the network nodes know to disregard the faulty transmission  The node tries again by repeating these same steps

18. 1 2 3 4

19.  10BaseT – 10Mbps/Baseband/Twisted Pair  Cat 3 or higher  Must follow 5-4-3 rule – can only have 5 network segments, 4 repeating devices, and only 3 populated segments  Maximum cable length is 100 meters  100BaseT - 100 Mbps/Baseband/Twisted Pair – Fast Ethernet  Does not follow 5-4-3 rule  Maximum cable length is 100 meters  Full-duplexing can increase to 200Mbps  1000BaseT – 1000 Mbps/Baseband/Twisted Pair  Uses all 4 pairs of a Cat 5 or higher twisted pair cable to transit at these speeds  Known as Gigabit Ethernet  Maximum cable length is 100 meters

20.  100Base-FX – 100Mbps/Baseband/Fiber Optic  Still considered Fast Ethernet  Maximum cable length is 2000 meters  Must use multimode fiber with at least 2 strands  1000Base-LX – 1000Mbps/Baseband/Long Wavelength (1300 nanometers)  Most common Gigabit Ethernet standard in use today  Single Mode Fiber maximum length is 5000 meters  Multimode Fiber maximum length is 550 meters  Excellent for backbone cabling  1000Base-SX – 1000Mbps/Baseband/Short Wavelength (850 nanometers)  Uses only multimode fiber optic cable  Maximum length with 50 micron core is 550 meters  Maximum length with 62.5 micron core is 275 meters

21.  10GBase-SR and SW – 10Gbps/Baseband/Short reach/R-works with LANs/W-works with SONET WANs  Uses multimode fiber  0 micron core maximum length is 300 meters  62.5 micron core maximum length is 66 meters  10GBase-LR and LW – 10Gbps/Baseband/Long reach/R-works with LANs/W-works with SONET WANs  Uses single mode fiber  Wavelengths of 1310 nanometers  Maximum cable length is 10,000 meters

22.  Uses single mode fiber only  Wavelength of 1550 nanometers  Maximum length is 40,000 meters

25.  Provides power to devices through the Ethernet cable  2 type of devices  Power Sourcing Equipment (PSE)  Powered Devices (PD)

26. For more information on this lesson, See Chapter 5 in the text book or email the Professor **All Slides and graphics were produced by Professor Patrick Hughes**