CCNA Cisco Certified Network Associate

Transkript

1 CCNA Cisco Certified Network Associate Agenda Dag 1 Kunskaptest Cisco Historia Certifiering CCNA Symboler Kap. 1 Lab.

2 Cisco Historia 1980 Len and Sandy Bosack worked in Stanford University communication trouble living room gateway server communicate using the IP protocol. 1884, they founded cisco Systems

3 Cisco Historia Cisco provides end-to-end networking solutions Cisco Systems offers such a broad range of networking and Internet services Cisco is indispensable.

4 Cisco Historia Hardware products Software Cisco Internetwork Operating System (IOS) Cisco Certified Internetwork Expert (CCIE) program

5 Certifiering CCNA

6 Cisco Historia CCIE (4 test) CCNP Cisco Certified Network Professional _career_certifications_and_learning_paths_ho me.html

7 CCNA The CCNA certification (Cisco Certified Network Associate) indicates a foundation in and apprentice knowledge of networking.

8 CCNA CCNA certified professionals can install, configure, and operate LAN, WAN, and dial access services for small networks

9 CCNA 100 nodes or fewer, including but not limited to use of these protocols: IP, IGRP, Serial, Frame Relay, IP RIP, VLANs, RIP, Ethernet, Access Lists.

10 CCNA e9/learning_certification_type_home.html

11 Symboler Router- Color and subdued Bridge Communication Server CiscoWorks Workstation Workgroup switch Layer 2 ATM Switch 100BaseT hub

12 Symboler 100BaseT hub Router switch processor (RSP) The brain of a switch router that handles routing functions on a switch. Putting those two together CISCO Big-Cat s 4000/5000 with route switch processors (RSP).

13 Symboler ISDN switch PC/Workstation Broadband router Token Ring The Cloud FDDI Represent a layer 2 FDDI topology

14 Symboler

15 Kapitel 1 Internetworking basics Network segmentation How bridges, switches, and routers are used to physically segment a network How routers are employed to create an internetwork

16 Internetworking Models 1960s and 1970s: Communications IBM (System Networks Architecture) Non-IBM (X.25)

17 Internetworking Models 1970s and 1980s: Networks Digital Equipment Corporation VAX system DECnet PC

18 Internetworking Models 1980s and 1990s: Internetworks

19 Internetworking Models 1990s: Global Internetworking

20 The OSI Reference Model 23 februari ISO 1977 OSI-modellen 1984 standard

21 The OSI Reference Model OSI-modellen, även känd under sitt standardnummer ISO 7498, är en modell för strukturering och uppbyggnad av utrustning för datorkommunikation som resultat av projektet Open Systems Interconnection (OSI) på initiativ av internationella teleunionen ITU och internationella standardiseringsorganisationen ISO.

22 Internetworking basics Tanken var att fastslå standarder för sju olika "lager" som skulle vara utbytbara, det vill säga att varje lager bara skulle kommunicera med lagret direkt nedanför och inte bekymra sig om vad som fanns längre ned.

23 Internetworking basics Modellen har fått en viss kritik, och eftersom den inte passar ihop speciellt bra med den konstruktionsfilosofi som genomsyrade ARPAnet (vilket fanns före modellens tillkomst) har den inte fått nämnvärt genomslag annat än i undervisningssyfte.

24 Internetworking basics Hos CCITT, som följde OSI-modellen, fanns flera protokoll för diverse syften (till exempel X.500, X.400, X.21 och V.24) som aldrig togs i bruk eller som senare fått annan utformning.

25 OSI modellens skikt

26 The lower layers

27 The upper layers

28 Layer functions

29 OSI-modellen i förhållande till protokollstacken för Internet Internets uppbyggnad med rötter i Arpanet och med TCP/IP som grund låter sig ogärna analyseras med hjälp av OSI-modellen. En ungefärlig klassificering av olika Internetstandarder från IETF och W3C kan se ut såhär:

30 OSI-modellen i förhållande till protokollstacken för Internet Applikation: FTP, Telnet, SMTP, HTTP Presentation: SSL, XML, HTML Session: RIP, SAP Transport: TCP, UDP

31 OSI-modellen i förhållande till protokollstacken för Internet Transport: TCP, UDP Nätverk: IP Länk: Ethernet Fysiskt media: Manchesterkodning på elektrisk ledare

32 OSI-modellen En router arbetar i skikt 3 Nätverk

33 OSI-modellen En Switch arbetar i skikt 2 Datalänk

34 Manchesterkodning Manchesterkodning är en självsynkroniserande bitkodning vid datorkommunikation.

35 Manchesterkodning Varje bit i dataströmmen kodas som två bitar, antingen 01 eller 10, så att varje bit överförs med minst en övergång mellar etta och nolla. Genom att det sändande systemet skickar med klockan i varje bit behöver inte det mottagande systemet tappa bitar på grund av att systemklockorna varierar lite.

36 Manchesterkodning Vid en första betraktelse kan systemet se ut att ge en inverterad utsignal om mottagaren bara läser 1/2 bit fel, men mottagaren upptäcker fort (vid en bitövergång i dataströmmen) att den är osynkroniserad då signalen inte följer kodningen och kan synkronisera om sig.

37 Manchesterkodning För att synkronisera alla mottagare i Ethernet inleds varje paket med att sändaren flera gånger i följd skickar oktetten 0xaa, vilka manchesterkodas (o.s.v.) så att mottagarna entydigt kan synkronisera sig.

38 OSI-modellen i förhållande till protokollstacken för Internet I IETF-standarderna finns inga vattentäta skott mellan nivåerna och inga krav på de tre översta nivåerna, vilket gör att man brukar baka ihop dessa tre och kalla dem "applikation" då modellen används i Internetsammanhang

39 Routers, switches, and bridges? Possible causes of LAN traffic congestion are Too many hosts in a broadcast domain (is the set of all devices on a network segment that hear all broadcasts sent on that segment) Broadcast storms.

40 Routers, switches, and bridges Multicasting Low bandwidth Adding hubs for connectivity to the network A large amount of ARP or IPX traffic (IPX is a Novell routing protocol that is like IP, but really, really chatty)

41 Routers, switches, and bridges Two advantages of using routers in your network are They don't forward broadcasts by default. They can filter the network based on layer 3

42 Routers and Switches Routers are used to connect networks together and route packets of data from one network to another. Routers, by default, break up a broadcast domain, which is the set of all devices on a network segment that hear all broadcasts sent on that segment. Breaking up a broadcast domain is important because when a host or server sends a network broadcast, every device on the network must read and process that broadcast unless you've got a router.

43 Routers and Switches When the router's interface receives this broadcast, it can respond by basically saying "Thanks, but no thanks," and discard the broadcast without forwarding it on to other networks. Even though routers are known for breaking up broadcast domains by default, it's important to remember that they break up collision domains as well.

44 Routers and Switches Two advantages of using routers in your network are They don't forward broadcasts by default. They can filter the network based on layer 3 (Network layer) information (i.e., IP address).

45 Routers and Switches Four router functions in your network can be listed as Packet switching Packet filtering Internetwork communication Path selection

46 Routers and Switches Routers are really switches, but they're actually what we call layer 3 switches. Unlike layer 2 switches that forward or filter frames, routers (layer 3 switches) use logical addressing and provide what is called packet switching. Routers can also provide packet filtering by using access-lists, and when routers connect two or more networks together and use logical addressing (IP), this is called an internetwork. Lastly, routers use a routing table (map of the internetwork) to make path selections and to forward packets to remote networks.

47 Routers, Switches, and Bridges Four router functions in your network can be listed as Packet switching Packet filtering Internetwork communication Path selection

48 Routers and Switches switches aren't used to create internetworks, they're employed to add functionality to an internetwork LAN. The main purpose of a switch is to make a LAN work better to optimize its performance providing more bandwidth for the LAN's users. And switches don't forward packets to other networks as routers do. Instead, they only "switch" frames from one port to another within the switched network.

49 Skilnad mellan router och switch Router Switch arbetar i layer 3 Skickar paketer Routers provide a separate broadcast domain for each interface. Switch Switch arbetar i layer 2 Optimera LAN prestanda Skickar ej paketer Växla frames från en port till en annan Switches create separate collision domains, but a single broadcast domain

50 Presentation Layer Provaides code formatting and conversion for applications

51 Session Layer Establishes, manages, and terminates sessions session between applications Coordinates applications as they interact on different host

52 Transport Layer Transport services allow users to segment and reassemble several upper-layer applications onto a same transport layer data stream

53 Connection-Oriented Session Acknowledge (Bekräfta)

54 Flow Control Congestion Hig-speed computer generate traffic faster than a network can transfer it Many computer simultaneously need to send datagrams trough a singel gateway or to a singel destination

55 Flow Control Buffer (memory)

56 Windowing Is a method to control the amount of information transferred end to end

57 Relaibility with Windowing

58 Positiv Acknowledgment

59 Network Layer Layer 3 functions to find the best path through the internetwork

60 Addresing: Network and Host

61 Addresing: Network and Host

62 Physical and Data-link Standars Separate Standards

63 LAN Data Link Sublayers Dlata Link layer formats de messages into pices, each called a data frame LLC (IEE 802.3) referers uppward to higerlayer software functions MAC (IEE 802.2) referers downward to lower-layer hardware functions OBS!

64 LLC Sublayer Functions Enable upper layers to gain inde pendence over LAN media acces Allow service access point (SAPs) From interface sublayers to upper layer function

65 Ethernet and IEEE 802.3

66 Ethernet and IEEE S Base2 up to 185 m. on coaxial cabel, 30 workstation on a singel segment 10 Base5 up to 500 m. on coaxial cabel, 2500 m. with repeaters, BaseT

67 Ethernet and IEEE Operation Carrier Sense Multiple Access with collision Detection (CSMA/CD) Protocol Cheks for the precense of a digital signal on the wire S3-19

68 Ethernet and IEEE Operation

69 Ethernet Cabling TX (transmitter) pins are connected to corresponding RX (receiver) pins.

70 Ethernet Cabling

71 Ethernet Cabling

72 Samma sladduppsättning i båda kontakter

73 Ethernet Cabling

74 Rolled cable Spegelvänd

75 Wireless Networking

76 Data Encapsulation

77 Data Encapsulation User information is converted to data for transmission on the network. Data is converted to segments and a reliable connection is set up between the transmitting and receiving hosts. Segments are converted to packets or datagrams, and a logical address is placed in the header so each packet can be routed through an internetwork.

78 Data Encapsulation Packets or datagrams are converted to frames for transmission on the local network. Hardware (Ethernet) addresses are used to uniquely identify hosts on a local network segment. Frames are converted to bits, and a digital encoding and clocking scheme is used. To explain this in more detail using the layer addressing, I'll us

79 The Cisco Three-Layer Hierarchical Model

80 The Cisco Three-Layer Hierarchical Model The core of any network design should be implemented for high-speed switching. This layer just wants to move the information around as quickly as possible.

81 The Cisco Three-Layer Hierarchical Model The distribution layer helps to re-distribute those fast moving information packets, but may be slowed down by some decisionmaking from a router.

82 The Cisco Three-Layer Hierarchical Model Finally the access layer is where users connect to the network. This is considered to be the slowest layer because of the extensive decision-making that may be taking place here.