CCNA Guide to Cisco Networking Chapter 2: Network Devices.
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Transcript of CCNA Guide to Cisco Networking Chapter 2: Network Devices.
![Page 1: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/1.jpg)
CCNA Guide to Cisco Networking
Chapter 2: Network Devices
![Page 2: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/2.jpg)
Objectives
• Explain the uses, advantages, and disadvantages of repeaters
• Explain the uses, advantages, and disadvantages of hubs
• Define wireless access points
• Define network segmentation
• Explain network segmentation using bridges
![Page 3: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/3.jpg)
Objectives (continued)
• Explain network segmentation using switches
• Explain network segmentation using routers
• Explain network segmentation using brouters and gateways
![Page 4: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/4.jpg)
Repeaters
• Length of cable used influence the quality of communication
• Attenuation• Repeaters repeat signals
– Clean and boost digital transmission– Analog networks use amplifiers to boost signal
• Repeaters only work with the physical signal– Cannot reformat, resize, or manipulate the data
• Physical layer (layer 1) device
![Page 5: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/5.jpg)
Repeaters (continued)
![Page 6: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/6.jpg)
Repeaters (continued)
![Page 7: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/7.jpg)
Hubs
• Generic connection device– Physical layer
• Connect several networking cables together
• Active hubs– Multiport repeaters
• Passive hubs
• Hubs and topology
![Page 8: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/8.jpg)
Hubs (continued)
![Page 9: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/9.jpg)
Advantages And Disadvantages Of Repeaters And Hubs
• Advantages of using repeaters– Extend network physical distance
– Do not seriously affect network performance
– Special repeaters connect different media
• Copper to fiber
• Disadvantages of using repeaters– Cannot connect different network architectures
• Token Ring and Ethernet
– Cannot reduce network traffic
![Page 10: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/10.jpg)
Advantages And Disadvantages Of Repeaters And Hubs
(continued)
• Disadvantages of using repeaters
• Do not segment the network– Repeat everything without discrimination– Number of repeaters must be limited
• Repeaters are part of a collision domain
![Page 11: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/11.jpg)
Wireless Access Points
• Wireless local area networks (WLANs)
• Wireless access points provide cell-based areas– Contains radio transceiver– Function like a hub– Bandwidth is shared– May also function as a wireless repeater
• Wireless clients
![Page 12: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/12.jpg)
Wireless Access Points (continued)
![Page 13: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/13.jpg)
Network Segmentation
• Carrier Sense Multiple Access with Collision Detection (CSMA/CD)
• Problems occur with too many nodes on the same network segment or collision domain
![Page 14: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/14.jpg)
Network Segmentation (continued)
• Collision– Back off algorithm– Back off period
• Segmentation– Collisions and retransmissions are reduced– Contention for bandwidth is reduced
![Page 15: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/15.jpg)
Network Segmentation (continued)
![Page 16: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/16.jpg)
Bridges
• Operate at the Data Link layer
• Forward or drop frames
• Cannot filter broadcasts
• MAC to segment # table
• MAC to segment # table initial development
![Page 17: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/17.jpg)
Bridges (continued)
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Transparent Bridges
• Also called learning bridges
• Build a table of MAC addresses as frames arrive
• Ethernet networks use transparent bridges
• Token Ring networks use source-routing bridges
![Page 19: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/19.jpg)
Source-Routing Bridges
• Used in Token Ring networks
• Rely of source of the frame transmission
• Explorer frames
![Page 20: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/20.jpg)
Translation Bridges
• Connect networks with different network architecture
• Example:– Token ring connecting to Ethernet
![Page 21: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/21.jpg)
Advantages And Disadvantages Of Bridges
• Advantages of using a bridge– Extend physical network– Reduce network traffic with minor
segmentation– Creates separate collision domains– Reduce collisions– Connect different architecture
![Page 22: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/22.jpg)
Advantages And Disadvantages Of Bridges
(continued)
• Disadvantages of using bridges– Slower that repeaters due to filtering– Do not filter broadcasts– More expensive than repeaters
![Page 23: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/23.jpg)
Switches
• Operate at the Data Link layer
• Increase network performance
• Virtual circuits between source and destination
• Micro segmentation
• Multiple virtual circuits are called “switched bandwidth”
![Page 24: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/24.jpg)
Switches (continued)
• Between two computers using a switch two collision domains are created each with dedicated bandwidth
• Between two hubs using a switch two collision domains are created each with shared bandwidth
• Filter based on MAC addresses
• Build tables in memory
![Page 25: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/25.jpg)
Switches (continued)
• Advantages of switches– Increase available network bandwidth– Reduced workload, computers only receive
packets intended for them specifically– Increase network performance– Smaller collision domains
![Page 26: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/26.jpg)
Switches (continued)
• Disadvantages of switches– More expensive than hubs and bridges– Difficult to trace network connectivity
problems through a switch– Does not filter broadcast traffic
![Page 27: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/27.jpg)
Switches (continued)
![Page 28: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/28.jpg)
Routers
• Provide filtering and network traffic control
• Used on LANs and WANs
• Connect multiple segments and networks
• Multiple routers create an “internetwork”
• Operate at the Network layer
![Page 29: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/29.jpg)
Routers (continued)
• Create a table to determine how to forward packets
• Filtering and traffic control base on logical addresses
![Page 30: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/30.jpg)
Physical Versus Logical Addresses
• MAC addresses– Data Link layer application– Used by switches, bridges, and routers– Used for directly connected devices
• Logical addresses– Network and transport protocols dictate the format of
the logical network layer address– TCP/IP, IPX/SPX– IP addresses are assigned manually or by software
![Page 31: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/31.jpg)
Physical Versus Logical Addresses (continued)
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Advantages And Disadvantages Of Routers
• Advantages of routers– Can connect networks of different architecture
• Token Ring to Ethernet
– Choose best path through or to a network– Create smaller collision domains– Create smaller broadcast domains
![Page 33: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/33.jpg)
Advantages And Disadvantages Of Routers
(continued)• Disadvantages of routers
– Only work with routable protocols– More expensive than hubs, bridges, and
switches– Routing table updates consume bandwidth– Increase latency due to a greater degree of
packet filtering and/or analyzing
![Page 34: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/34.jpg)
Advantages And Disadvantages Of Routers
(continued)
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Brouters
• Hybrid device
• Functions as a router for routable protocols
• Functions as a bridge for non-routable protocols
• Operates at Data Link and Network layers
![Page 36: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/36.jpg)
Gateways
• A gateway is a combination of hardware and software
• Translate between different protocol suites
• Operates on all 7 layers of the OSI model
• Most negative on network performance– Latency
![Page 37: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/37.jpg)
Summary
• Network administrators use devices to control and extend the usable size of a network
• These devices include repeaters, hubs, bridges, switches, routers, brouters, and gateways
• Repeaters work against attenuation by cleaning and repeating signals that they receive on a network
• Repeaters work at the Physical layer of the OSI model
• They cannot connect different network architectures
![Page 38: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/38.jpg)
Summary (continued)
• Repeaters do not reduce network traffic or segment the network
• A hub ties several networking cables together to create a link between different stations on a network
• An active hub has its own electrical power and acts as a repeater, whereas a passive hub provides no signal regeneration
• Hubs operate at the Physical layer of the OSI model and do not segment the network
• Network segmentation is the process of isolating hosts onto smaller segments to reduce the possibility of collisions
![Page 39: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/39.jpg)
Summary (continued)
• Bridges and switches are two devices commonly used to segment networks
• Bridges provide network segmentation by examining the MAC address that is sent in the data frame
• Bridges can use transparent bridging or source-route bridging to determine which segment includes a specific physical address
• Bridges operate at the Data Link layer of the OSI model
![Page 40: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/40.jpg)
Summary (continued)
• Switches increase network performance by reducing the number of frames transmitted to the rest of a network
• They do this by opening a virtual circuit between the source and the destination
• Switches operate at the Data Link layer of the OSI model
![Page 41: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/41.jpg)
Summary (continued)
• Routers operate at the Network layer of the OSI model and provide filtering and network-traffic control on LANs and WANs
• They can connect multiple segments and networks
• On a TCP/IP network, routers use IP addresses to route packets to the correct network segment
• Routers use information from routing tables to move packets from one network to another
![Page 42: CCNA Guide to Cisco Networking Chapter 2: Network Devices.](https://reader036.fdocuments.in/reader036/viewer/2022062409/5697bf9c1a28abf838c93287/html5/thumbnails/42.jpg)
Summary (continued)
• A brouter is a hybrid device that functions both as a bridge for non-routable protocols and as a router for routable protocols
• Brouters operate at both the Data Link and Network layers
• Gateways are usually a combination of hardware and software and are used to translate between different protocols
• They usually operate at layer 4 and above in the OSI model