CCNA Cisco Certified Network Associate

Transcription

1 CCNA Cisco Certified Network Associate Agenda Dag 17 Kap 11 LAB

2 Wide Area Networks (WAN) In the past. Distance Bandwidth lease infrastructure To day (LAN) Wireless Big pipes no price any more Own infrastructure

3 WAN

4 Defining WAN Terms Customer premises equipment (CPE) is equipment that's owned by the subscriber and located on the subscriber's premises. Demarcation point is the spot where the service provider's responsibility ends and the CPE begins.

5 Defining WAN Terms Local loop connects the demarcation point to the closest switching office, called a central office. Central office (CO) This point connects the customers to the provider's switching network. A central office (CO) is sometimes referred to as a point of presence (POP).

6 Defining WAN Terms Local loop CO CPE

7 Defining WAN Terms Toll network is a trunk line inside a WAN provider's network. This network is a collection of switches and facilities owned by the ISP.

8 Defining WAN Terms DET data terminal equipment: Any device located at the user end of a user-network interface serving as a destination, a source, or both. DTE includes devices such as multiplexers, routers, protocol translators, and computers. The connection to a data network is made through data communication equipment (DCE) such as a modem, using the clocking signals generated by that device.

9 Defining WAN Terms DCE data communications equipment (as defined by the EIA) or data circuit-terminating equipment (as defined by the ITU-T): The mechanisms and links of a communications network that make up the network portion of the user-to-network interface, such as modems. The DCE supplies the physical connection to the network, forwards traffic, and provides a clocking signal to synchronize data transmission between DTE and DCE devices.

10 WAN Connection Types Leased lines Circuit switching Packet switching

11 WAN Connection Types Leased lines Typically, these are referred to as a point-topoint connection or dedicated connection. A leased line is a pre-established WAN communications path from the CPE, through the DCE switch, to the CPE of the remote site, allowing DTE networks to communicate at any time with no setup procedures before transmitting data.

12 Leased lines

13 Circuit switching Phone call. Circuit switching uses dial-up modems or ISDN, and is used for lowbandwidth data transfers. The big advantage is cost you only pay for the time you actually use. No data can transfer before an end-to-end connection is established.

14 Circuit switching

15 Packet switching This is a WAN switching method that allows you to share bandwidth with other companies to save money. Packet switching can be thought of as a network that's designed to look like a leased line, yet charges you (and costs) more like circuit switching.

16 Packet switching There is a downside: If you need to transfer data constantly, forget about this option. Just get yourself a leased line. Packet switching will only work well if your data transfers are bursty in nature. Frame Relay and X.25 are packet-switching technologies. Speeds can range from 56Kbps to T3 (45Mbps).

17 Packet switching

18 Cisco WAN Support Frame Relay A packet-switched technology. is a Data Link and Physical layer specification that provides high performance. Frame Relay is a successor to X.25, except that much of the technology in X.25 used to compensate for physical errors (noisy lines) has been eliminated.

19 Cisco WAN Support Frame Relay can be more cost-effective than point-to-point links, and can typically run at speeds of 64Kbps up to 45Mbps (T3). Frame Relay provides features for dynamic bandwidth allocation and congestion control

20 Cisco WAN Support ISDN Integrated Services Digital Network (ISDN) is a set of digital services that transmit voice and data over existing phone lines.

21 Cisco WAN Support LAPB Link Access Procedure, Balanced (LAPB) was created to be a connectionoriented protocol at the Data Link layer for use with X.25. It can also be used as a simple data link transport. LAPB causes a tremendous amount of overhead because of its strict timeout and windowing techniques.

22 Cisco WAN Support LAPD Link Access Procedure, D-Channel (LAPD) is used with ISDN at the Data Link layer (layer 2) as a protocol for the D (signaling) channel. LAPD was derived from the Link Access Procedure, Balanced (LAPB) Protocol and is designed primarily to satisfy the signaling requirements of ISDN basic access.

23 Cisco WAN Support HDLC High-Level Data-Link Control (HDLC) was derived from Synchronous Data Link Control (SDLC), which was created by IBM as a Data Link connection protocol. ISO standard bit-oriented Data Link layer protocol.

24 Cisco WAN Support HDLC is a protocol at the Data Link layer, and it has very little overhead compared to LAPB. HDLC wasn't intended to encapsulate multiple Network layer protocols across the same link.

25 Cisco WAN Support The HDLC header carries no identification of the type of protocol being carried inside the HDLC encapsulation. Because of this, each vendor that uses HDLC has their own way of identifying the Network layer protocol, which means that each vendor's HDLC is proprietary for their equipment.

26 Cisco WAN Support HDLC is a point-to-point protocol used on leased lines. No authentication can be used with HDLC.

27 Cisco WAN Support PPP Point-to-Point Protocol (PPP) is an industry-standard protocol. Because all multiprotocol versions of HDLC are proprietary, PPP can be used to create pointto-point links between different vendors' equipment.

28 Cisco WAN Support Point-to-Point Protocol (PPP) is a Data Link layer protocol that can be used over either asynchronous serial (dial-up) or synchronous serial (ISDN) media.

29 Cisco WAN Support It uses a Network Control Protocol field in the Data Link header to identify the Network layer protocol. It allows authentication and multilink connections and can be run over asynchronous and synchronous links. The basic purpose of PPP is to transport layer 3 packets across a Data Link layer point-to-point link.

30 Point-to-Point Protocol stack

31 Cisco WAN Support ATM Asynchronous Transfer Mode (ATM) was created for time-sensitive traffic, providing simultaneous transmission of voice, video, and data. ATM uses cells instead of packets that are a fixed 53 bytes long. It also can use isochronous clocking (external clocking) to help the data move faster.

32 Cabling the Wide Area Network How to connect your WAN. Serial Transmission DTE and DCE.

33 Cabling the Wide Area Network

34 Cabling the Wide Area Network

35 Link Control Protocol (LCP) Configuration Options Authentication Compression Error detection Multilink PPP callback

36 Authentication This option tells the calling side of the link to send information that can identify the user. The two methods are PAP and CHAP.

37 Compression This is used to increase the throughput of PPP connections by compressing the data or payload prior to transmission. PPP decompresses the data frame on the receiving end.

38 Error detection PPP uses Quality and Magic Number options to ensure a reliable, loop-free data link.

39 Multilink Starting in IOS version 11.1, multilink is supported on PPP links with Cisco routers. This option allows several separate physical paths to appear to be one logical path at layer 3.

40 PPP callback PPP can be configured to call back after successful authentication. PPP callback can be a good thing for you because you can keep track of usage based upon access charges, for accounting records, or a variety of other reasons.

41 PPP Session Establishment Link-establishment phase Authentication phase Network layer protocol phase