Ccna Lan Switching and Wireless Study Guide Chapter 2
Chapter 1 Study Guides. 1. What are the three layers of the hierarchical network design model? – access – distribution – core Access, distribution and core. 2. What are the advantages of designing LANs using the hierarchical model? – scalability – redundancy – performance – security – manageability – maintenanceand the network (scalability), and it should be easier to maximise performance. 3. What is the purpose of the access layer? – to provide a means of connecting devices to the network and controlling which ones are allowed.
It allows end devices toconnect to the network and controls which devices may connect 4. What sort of devices are found at the access layer? – PC’s, faxes, printers, WAP’s, routers, switches, hubs 5. What is the purpose of the distribution layer? – aggregates data received from access layer switches before it is transmitted to core layer. 6. What sort of devices are found at the distribution layer? – switches 7. What is the purpose of the core layer? – interconnectivity between distribution layer devices, so it is important for the core to be highly available and redundant 8.
What is a collapsed core model and where might it be used? – in small networks where the distribution layer and core layer are combined into one layer. 9. What is a wiring closet? – an area where the hardware is held and the electrical connections are made. 10. Why is it not easy to see the logical hierarchical design of a network when looking at the network layout in a building? – because the physical layout of a network differs from the logical layout. 11. Why is redundancy important in a network? – If one switch fails there is another route which increases availability 12.
Which layers normally have redundancy built in? – the core and distribution 13. How can the hierarchical design help to give high performance? – traffic is appropriately routed through the network at each level. 14. How can switches at the different layers contribute to network security? – Access layer switches can be configured who to allow and distribution layer switches allow flexibility to use more advanced security policies such as access control policies that define which communication protocols are deployed on the network and where they are permitted to go. (pg5) 15.
How does a hierarchical design help to make a network manageable? – switches have similar set ups at their designated layer making configuration checking and configuring new switches easier. 16. Should the same type of switch be used at each layer of the hierarchical design? – no at the access layer less expensive switches can be used and at the core and distribution layers speed is the necessity. 17. What is “network diameter” in hierarchical network design? – the number of devices that a packet has to cross before it reaches its destination 18. What is network device latency? the time spent by a device as it processes a packet or frame 19. What sort of processing does a switch have to do on each packet? – each switch has to determine the destination MAC address of the frame, check it MAC address table, and forward the frame out the appropriate port 20. How can bandwidth aggregation be implemented? – two or more connections are combined to create a logically singular higher bandwidth connection (pg8) 21. Why is redundancy not normally provided at the access layer? – it’s not worth the cost to add the redundancy directly to each access device 21.
When designing a new network, at which layer would you start? – access layer. It ensures that when you have all network devices have access to the network then you can work up. 22. What is a converged network? – a network with voice and video communication on a data network 23. What factors have slowed the move towards converged networks? – special equipment, QoS management, people with the expertise 24. What does the Catalyst 3560E switch provide that the 3560 switch does not? – faster forwarding rates 25. Which catalyst switch has forwarding rates up to 720 Gbps? – 6500