 |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
CCNA |
|
|
|
Course notes: CISCO Exam 640-801 |
|
|
|
 |
|
|
|
Menu Contents Page 1: |
|
|
|
 |
|
Introduction to CCNA exam notes |
|
|
|
|
|
|
|
OSI Model |
|
|
|
|
|
|
|
Session Protocols |
|
|
|
|
|
|
|
LAN Technologies |
|
|
|
|
|
|
|
LAN Protocols |
|
|
|
|
|
|
|
USER Selection |
|
|
|
|
|
Introduction: |
|
|
|
Course notes taken by Craig Ellis, qualified CCNA+MCP TCP/IP-NT4) |
|
|
| Covered in the exam course notes will be OSI model definitions, LAN technologies, traffic segmentation, CISCO router components, IP addressing, configuring your router and WAN technologies. What you will need to help you study for this exam is: |
|
|
| 2 CISCO 2501 routers with IP and IPX software feature set. |
|
|
| 2 DTE / DCE v.35 cables |
|
|
| 2 Ethernet transceivers |
|
|
| 2 Console cables with adapters |
|
|
| The Exam: There is one exam to take for the CISCO CCNA course (Exam Number 640-801). Your are asked between 55 to 65 questions (three simulation), you have 90 minutes to complete the test, a apx. score of 849 needed to pass. The cost of the exam is approximately £125 (UK). Details of the exam may be found at www.2test.com |
|
|
|
 |
|
|
|
 |
|
|
|
OSI Model: |
|
|
| The Open System Interconnect (OSI) model consists of 7 layers: |
|
|
| Layer 7 Application (e-mail, Accessing remote files, printers & databases) |
|
|
| Layer 6 Presentation (Protocol conversion, Data Translation) |
|
|
| Layer 5 Session (Establishes communication connection, Transmit length, time) |
|
|
| Layer 4 Transport (Error handling, Flow control ? Buffer availability) |
|
|
| Layer 3 Network (Route taken, addressing messages) |
|
|
| Layer 2 Data-Link (Frame transmission, acknowledgement) |
|
|
| Layer 1 Physical (Cabling types, Network Interface Cards) |
|
|
| |
|
|
| The Application Layer: |
|
|
| Provides applications with network and inter-network services |
|
|
| File and print services |
|
|
| E-Mail (Electronic Mail) |
|
|
| WWW / HTTP (World Wide Web / Hyper Text Transport Protocol) |
|
|
| TELNET (see RFC854) |
|
|
| FTP (File Transfer Protocol) |
|
|
| The Presentation Layer: |
|
|
| Data conversion and translation |
|
|
| Encryption, Decryption |
|
|
| ASCII to EBCDIC (American Standard Code for Information Interchange / Extended binary coded decimal interchange code) |
|
|
| Multimedia - TIFF/JPEG/PICT (Image formats) |
|
|
| Sound - MIDI/MPEG/Quicktime (Sound formats) |
|
|
| The Session Layer: |
|
|
| Controls dialog between 2 applications on different hosts |
|
|
| NFS (Network File Service) |
|
|
| SQL (Structured Query Language) |
|
|
| X Windows (Multi-tasking windowing and graphics system) |
|
|
| NetBIOS (Network basic input/output system) |
|
|
| RFC (Request For Comments) |
|
|
| The Transport Layer: |
|
|
| Controls end to end communications between 2 processes running on different hosts |
|
|
| Provides connection oriented or connection-less services to upper layers |
|
|
| Uses client and server port addresses to identify processes running within a host |
|
|
| Client ports: Are randomly chosen from range above 1024 |
|
|
| Server ports: Well known port range 0 - 255, Proprietary ports range 256 - 1023 |
|
|
| The Network Layer: |
|
|
| IP, IPX, and DDP (Internet Protocol / Inter-network Packet Exchange / Datagram Delivery Protocol) |
|
|
| Logical addressing |
|
|
| Routers |
|
|
| Routing protocols: |
|
|
| RIP (Routing Information Protocol) |
|
|
| OSPF (Open Shortest Path First) |
|
|
| IGRP (Interior Gateway Routing Protocol) |
|
|
| EIGRP (Enhanced IGRP) |
|
|
| |
|
|
| The Data Link Layer: |
|
|
|
 |
|
 |
|
|
| |
|
|
| 2 sub-layers: Defined by IEEE (Institute of Electrical and Electronics Engineers) |
|
|
| LLC (802.2) (Logical Link Control) |
|
|
| MAC (Media Access Control) |
|
|
| Layer 2 devices use MAC addresses |
|
|
| Bridges |
|
|
| Switches |
|
|
| |
|
|
| The Physical Layer: |
|
|
| Electrical and Mechanical characteristics |
|
|
| Signal Encoding |
|
|
| Synchronisation |
|
|
|
|
|
|
|
|
|
|
|
Session Protocols |
|
|
|
|
|
|
| There are 2 different types of protocols: |
|
|
|
Connectionless |
|
Connection Oriented |
|
|
|
No session set-up |
|
Session set-up |
|
|
|
No session tear-down |
|
Session tear-down |
|
|
|
No acknowledgements |
|
Acknowledgements |
|
|
|
No sequencing |
|
Sequencing |
|
|
|
No flow control |
|
Flow control |
|
|
|
No keep alives |
|
Keep alives |
|
|
|
 |
|
 |
|
|
| |
|
|
| A TCP client has to set-up a session with a server before sending data. (handshaking). |
|
|
| Also when completion of transmission the client/server has to 'handshake' to teardown session. |
|
|
| Sessions can use 'sliding windows' if the vendor has set-up the option, used in send / acknowledgement of data. |
|
|
| You would have to set-up the send/receive window, flow control buffer and keep alive state. |
|
|
| The Sliding Windows option makes data transmission fast because the server doesn't have to keep acknowledging each window. |
|
|
| The Client is always in control of the session. |
|
|
| |
|
|
| |
|
|
| |
|
|
| |
|
|
| |
|
|
|
|
|
|
|
|
|
|
|
LAN TECHNOLOGIES |
|
|
| LAN devices used in today's networking environment include: |
|
|
| Repeaters / Hubs / Concentrators |
|
|
| Physical layer device |
|
|
| Used to extend the distance of the network |
|
|
| Amplifies and bit repeats |
|
|
| Protocol independent |
|
|
| No traffic segmentation |
|
|
| Generates a new preable (used to sequence devices and know what is data) |
|
|
| Bridges / Switches |
|
|
| Exist as layer 2 devices |
|
|
| Floods, then forwards data |
|
|
| Uses destination hardware address to make decisions about forwarding |
|
|
| Learns where devices are from source hardware address |
|
|
| Protocol independent |
|
|
| Used for Non routable protocols i.e. NetBEUI |
|
|
| Do not filter broadcast or multicast traffic |
|
|
| Do not define separate networks |
|
|
| Each port on a bridge / switch defines a separate Collision Domain. |
|
|
| Bridges: |
|
|
| Store and forward devices |
|
|
| Examines the frame and performs a CRC (Cyclic Redundancy Check) |
|
|
| Does not pass on bad frames |
|
|
| Set-up the 'spanning tree' option to avoid network 'loops' if your bridge has this option. |
|
|
| Switches: |
|
|
| 3 main switching methods are: |
|
|
| Cut Through - looks at the first 6 bytes of the destination MAC address only |
|
|
| Fragment free cut through - looks at the first 64 bytes only |
|
|
| Store and forward - looks at the entire frame |
|
|
| Routers and Brouters: |
|
|
| Protocol independent - understand protocol used network layer 3 |
|
|
| Network orientated - where to send the data |
|
|
| Used to connect for example, Token Ring to Ethernet |
|
|
| Brouter - router that can bridge traffic (NetBEUI - no layer 3 info) |
|
|
| VLAN's - Virtual LAN's |
|
|
| Set-up by user using switches assigning ports to different networks running different speeds. |
|
|
| Switches have to be linked to a router to assign across an inter-network |
|
|
| Gateway: |
|
|
| Converts one language to another i.e. Microsoft protocol to Novell's protocol, across a network |
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
LAN PROTOCOLS |
|
|
| Local Area Network protocols used in today's network environment are: |
|
|
| Ethernet / Fast Ethernet |
|
|
| Half Duplex: |
|
|
| 1. Supported by all 10BaseX and 100BaseX standards |
|
|
| 2. Stations listen for collisions whilst transmitting data |
|
|
| 3. Single cable type is similar to a narrow one way bridge |
|
|
| Three IEEE 100BaseX standards |
|
|
| TX: |
|
|
| 1. Uses same 2 twisted pair as 10mb |
|
|
| 2. Supports full duplex |
|
|
| 3. 4b5b encoding |
|
|
| FX: |
|
|
| 1. Half Duplex - MM 412 metres |
|
|
| 2. Full Duplex - MM 2km or SM 10km |
|
|
| 3. 4b5b encoding |
|
|
| T4: |
|
|
| (Uses 4 pairs) |
|
|
| 1. 3 pairs for Tx and Rx |
|
|
| 2. 1 pair for collision detection |
|
|
| 3. 8b6t encoding |
|
|
| 4. Does not support full duplex mode |
|
|
| Full Duplex |
|
|
| No Collisions |
|
|
| Requires a dedicated point to point connection between two devices |
|
|
| Supported by 10 and 100Base TX and FX standards |
|
|
| Both ends must support full duplex at the software and hardware level |
|
|
| Max distance limitations based on media |
|
|
| Must disable the transceivers loopback and collision detection function |
|
|
|
Four Ethernet Encapsulations |
|
|
|
Industry Naming |
|
Cisco Naming |
|
|
|
Ethernet II |
|
Arpa |
|
|
|
Ethernet 802.3 |
|
Novell Ether |
|
|
|
|
|
|
IEEE Compliant frames |
|
|
|
|
|
|
Ethernet 802.3 |
|
SAP |
|
|
|
Ethernet SNAP |
|
SNAP |
|
|
| |
|
|
| Token Ring: |
|
|
| More resilient under heavy data transfer loads |
|
|
| Data runs in a ring formation, each station receives and then repeats the signal to its downstream neighbours |
|
|
| Collisions don't happen because stations can't transmit unless they have a token |
|
|
| FDDI: (File Distributed Data Interface) |
|
|
| Running like token ring |
|
|
| Can run very long distances |
|
|
| Very high speed data transfers |
|
|
|
|
|
|
|
|
|
|
|
Selection Menu |
|
|
|
Cisco page 1 |
|
|
Cisco CCNA page 2 |
|
|
Cisco CCNA page 3 |
|
|
Cisco CCNA page 4 |
|
|
TCP/IP Microsoft |
|
|
|
PLEASE READ FOOTNOTE BY AUTHOR ON CCNA PAGE 4, THANK YOU! |
|
|
|
  |
|
|
|
SemSim Cisco CCNA Free Learning Center (click to access SemSim website) |
|
|
|
|
|
|
 |
|
|
|
|
