Horus CCENT study guide I hope this is useful -

horusthesunhorusthesun Member Posts: 289
CCNA Study Guide

Book 1

TCP/IP

Application: HTTP, POP3, SMTP-Provides services to the applications running on a computer.

Transport: TCP, UDP-Controls QoS. Uses segments.

Internet: IP- IP addressing. Uses Packets

Network: Ethernet, Frame Relay- Routing and physical protocol standards (Physical and DataLink). Uses Frames.

OSI

Application- Interface between Network and Applications. Includes Authentication

Presentation- Defines format and organization. Includes encryption

Session- Establishes and maintains end to end bidirectional flows. Includes transaction flows.

Transport- Provides many services between two host computers such as connection establishment and termination, flow control, error recovery and segmentation of large data blocks.

Networking- Logical addressing and routing.

Data-link- Formats data into frames. Defines rules for when medium should be used. Defines means of which to recognize transmission errors. Switches work on this layer.

Physical- Physical specifications, such as voltage, frequency, optical and connectors. Hubs and switches work on this layer.


LAN

CSMA/DC- Detects and “repairs” collisions by stopping communications when one occurs.

Ethernet 10 10Base-T 802.3 100m Copper
Fast Ethernet 100 100Base-TX 802.3u 100m Copper
Gigabit 1000 1000BaseLX 802.3z 5km(LX) Fiber 550m (SX) Fiber
Gigabit 1000 1000Base-T 802.3ab 100m Copper

CSMA/DC Steps

1. A device with a packet to send waits until Ethernet is silent

2. When silent, sender(s) begins to send frames

3. Sender(s) listen to see if there is a collision

4. If so, sending devices send a jamming signal to say there was one

5. Once jamming is complete, each sender randomizes a timer and waits to resend

6. When timer is up, process starts all over

WAN Layer 1

CSU- Chanel Service Unit- Interface to Telco lines, connected to router with short cable

DSU- Data Service Unit- Interface to Telco lines, connected to router with short cable

CPE- Customer Premises Equipment

DCE- Data Communications Equipment (Sends Clocking)

DTE- Data Terminal Equipment (receives Clocking)

PCM- Pulse Code Modulation- ADC

TMD- Time Division Multiplexing- Combining slow lines to make a fast one

60 pin D-Shell cable goes to router

CSU/DSU gets: EIA/TIA-232, EIA/TIA-449, V.35, x.21, EIA-530

CSU/DSU to Telco gets RJ-48



WAN Layer 2

HDLC-High-level Data-Link Control- Data-Link layer protocol for point to point links

PPP- Point to Point Protocol- Data-Link layer protocol for point to point links

DLCI- Data-Link connection identifier- Header that holds an address

Packet Switching- Allows one router and CSU/DSU to connect to several (100+) branch sites

Frame Relay- Multicast, Telco examines packets, AKA Frame switching

DCE- Frame Relay switches

TDET- Routers/Customer equipment

PVC- Permanent Virtual Circuit

CIR- Committed Information Rate

Leased Lines: AKA: leased circuit, link, serial link, serial line, point-to-point link, circuit pointto-point WAN- Acts like a direct circuit between two sites, acts like a set of two twisted pairs of wires.



Standard HDLC Frame
| 1 | 1 | 1 | Variable | 4 |
| Flag | Address | Control | Data | FCS |

CISCO HDLC Frame

| 1 | 1 | 1 | 2 | Variable | 4 |
|Flag | Aggress | Control | Type | Data | FCS |




More to come need to reformat data copy pasta isn't working .... no word wrap

fixing wall of text

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