OSI Data Link Layer. CCNA1-1 Chapter 7

Transkripsi

1 OSI Data Link Layer CCNA1-1 Chapter 7

2 OSI Data Link Layer Accessing the Media CCNA1-2 Chapter 7

3 OSI Data Link Layer Provides the user interface Organize data for network transfer Segmentation and managing communications Exchange data over common media CCNA1-3 Chapter 7

4 Supporting and Connecting to Upper Layer Dua fungsi dasar: mengijinkan upper layers untuk mengakses media menggunakan framing. Mengontrol bagaimana data ditempatkan pada media dan diterima dari media menggunakan media access control (MAC) and error detection. CCNA1-4 Chapter 7

5 Supporting and Connecting to Upper Layer Terminology CCNA1-5 Chapter 7

6 Supporting and Connecting to Upper Layer Protokol pengatur bagaimana memformat sebuah frame untuk digunakan pada media tersebut Protokol yang berbeda untuk media yang berbeda Menerima frame Decapsulasi ke sebuah paket Membuat frame baru untuk media Forward frame baru CCNA1-6 Chapter 7

7 Controlling Transfer Across Local Media Protokol Layer 2 menentukan enkapsulasi paket ke dalam frame dan teknik untuk mendapatkan paket dan media yang dienkapsulasi dari masing-masing media. Teknik ini disebut metode Media Access Control (MAC). Media yang berbeda mungkin memerlukan metode MAC yang berbeda. Setiap jenis media yang ditemui dapat memiliki karakteristik yang berbeda. (Terutama router dimana beberapa jenis media berbeda bisa hidup bersama.) CCNA1-7 Chapter 7

8 Controlling Transfer Across Local Media WAN Header WAN Trailer LAN Header Packet LAN Trailer Different media Different characteristics Different MAC method CCNA1-8 Chapter 7

9 Controlling Transfer Across Local Media Protokol dapat dikonfigurasi pada perangkat dan menentukan jenis enkapsulasi(mac method). Different media Different characteristics Different MAC method CCNA1-9 Chapter 7

10 Creating a Frame Deskripsi sebuah frame adalah elemen kunci dari setiap protokol. Protokol yang berbeda memerlukan Informasi yang berbeda agar berfungsi dengan baik. Dimana node berkomunikasi dengan satu sama lain. Ketika komunikasi antara node individu dimulai dan kapan berakhir. kesalahan yang terjadi saat node dikomunikasikan Node yang akan berkomunikasi berikutnya. CCNA1-10 Chapter 7

11 Creating a Frame Frames menempuh media sebagai aliran bit. Framing paket menyisipkan informasi kontrol dalam bidang tertentu CCNA1-11 Chapter 7

12 Connecting Upper-Layer Services to the Media Network devices have both a hardware and software component. CCNA1-12 Chapter 7

13 Connecting Upper-Layer Services to the Media Data Link Layer mempersiapkan paket dari perangkat lunak upper layer untuk transmisi melalui media fisik CCNA1-13 Chapter 7

14 Standards Not defined by RFCs as in the other layers. Defined by engineering organizations. CCNA1-14 Chapter 7

15 Connecting Upper-Layer Services to the Media IEEE Logical Link Control (LLC) Sub-Layer Frames the network layer packet Identifies the network layer protocol Media Access Control (MAC) Sub-Layer Addresses the frame Marks the beginning and end of the frame CCNA1-15 Chapter 7

16 Placing Data on the Media Mengatur penempatan data pada media disebut Media Access Control. Media sharing: Jika dan bagaimana node berbagi media. Topology: Bagaimana koneksi muncul ke Data Link Layer. CCNA1-16 Chapter 7

17 MAC for Shared Media Two Basic Methods: More in Chapter 9 CCNA1-17 Chapter 7

18 MAC for Non-Shared Media Point-to-Point Connections: Type of communication. Half Full Duplex CCNA1-18 Chapter 7

19 Logical Topology vs Physical Topology Physical Topology: (Antara Susunan node dan koneksi fisik More in Chapter 9). Logical Topology: Cara jaringan mentransfer frame antar node. Penggunaan koneksi virtual antar node terlepas dari koneksi fisik sebenarnya. Point-to-Point Multiaccess Ring CCNA1-19 Chapter 7

20 Point-to-Point Logical Topology Concerned with full or half duplex. CCNA1-20 Chapter 7

21 Multiaccess Logical Topology Mengaktifkan sejumlah node untuk berkomunikasi menggunakan media bersama yang sama. A sends to E Check for other transmissions Media available Transmit X X X B needs to send to D I ll wait Media NOT available Check for other transmissions CCNA1-21 Chapter 7

22 Ring Logical Topology Setiap node menerima frame secara bergantian. Jika tidak ditujukan ke node, itu akan meneruskannya. Is it for me? Yes No A sends to D Is it for me? Is it for me? No CCNA1-22 Chapter 7

23 OSI Data Link Layer Addressing and Framing Data CCNA1-23 Chapter 7

24 The Frame Ada banyak protokol Data Link Layer yang berbeda. The Data Link Layer protocol describes the features required for the transport of frames. Integrated into the encapsulation process. Tidak ada protokol frame tunggal yang memenuhi kebutuhan semua transportasi data di semua jenis media. CCNA1-24 Chapter 7

25 The Frame Namun, setiap protokol Data Link Layer dibangun menggunakan format dasar yang sama.it s the contents that differ. Header Data Trailer CCNA1-25 Chapter 7

26 Framing: Role of the Header Contains the control information required by the protocol. Some sample fields Start of Frame Source and Destination MAC Addresses Priority/Quality of Service Type/Length Logical Connection Control Physical Link Control Flow Control Congestion Control CCNA1-26 Chapter 7

27 Framing: Role of the Header Specific bit sequence that indicates to the receiving device that the frame starts here. For example: Header Start Address Type/Length Data Trailer The source and destination MAC addresses. A code identifying the type of frame OR the total length of the frame. CCNA1-27 Chapter 7

28 Addressing: Where the Frame Goes The addresses used this layer are referred to as physical addresses. They are the burned-in MAC addresses of the network device (PC: NIC, Router: Physical port). They are only used for local delivery. If the frame must be transported to another segment, the frame is re-encapsulated by the receiving device and forwarded. Header Start Address Type/Length Data Trailer CCNA1-28 Chapter 7

29 Addressing: Where the Frame Goes OR send as a broadcast The Data Link Layer protocol will define the addressing required to move the frame through the network. CCNA1-29 Chapter 7

30 Framing: Role of the Trailer Frame Check Sequence (FCS): Used to provide basic error checking, usually with a Cyclic Redundancy Check (CRC). - Sending device uses an algorithm on the bits of the header and data portions. - The resulting value is placed in the FCS field. - Receiving device does the same thing. - If the values match no error. - If the values do not match frame discarded. Header Data FCS Trailer Stop A specific sequence of bits that indicate the end of the frame. CCNA1-30 Chapter 7

31 Sample: Data Link Layer Frames Point-to-Point Protocol (PPP) High Level Data Link Control Protocol (HDLC) Frame Relay Protocol Ethernet Protocol CCNA1-31 Chapter 7

32 Ethernet Protocol for LANs CCNA1-32 Chapter 7

33 Point-to-Point Protocol for WANs CCNA1-33 Chapter 7

34 Wireless Protocol for LANs CCNA1-34 Chapter 7