ccnp学习笔记 OSI Model Overview

  telnet远程登入的另一种方法

1 在R1和R2上配置IP

R1 DCE端#数据连通设备#

 int s0/0/0

ip add 192.168.1.1 255.255.255.0

clock rate 64000 #只在DCE端配置#

exit

R2 DTE #数据终端设备#

int 是0/0/0

ip add 192.168.1.2 255.255.255.0

exit

2 在R2上

enable

configure terminal

enable password 123

line vty 04

login local #使用本地的验证数据来验证远程telnet是否合法#

exit

username ccna password ccnp#定义本地验证数据库#

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     Network Structure Defined By Hierarchy

 Core Layer :

          Fast transport to enter prise   services

 Distribution Layer:

          Aggregation point

Access Layer:

          End station entry point to the network       #end station 终端#

                                    @@@@@@@@@@

      OSI Model Overview

Application

Presentation

Session

Transport

Network

Data Link

Physical

下四层重要

Transport :

              Reliable or unreliable delivery#TCP  UDP  SPX#

              Error correction before retransmit

Network:

              Provide logical addressing which routers use for  path determination        #IP  IPX#

Data Link:

              Aombines bits into bytes and bytes into frames

              Access to media a using MAC address

              Error detection not correction

                   #802.3/802.2 HDLS ATM PPP Frame-relay#

Physical:

            Move bits between devices

            Specifies voltage,wire speed and pin-out cables

             #EIA/TIA-232#

      @@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@

CSMA/CD 是什么

netstat -na   三次握手的实质 是什么

     ？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？？

*Hub

All devices  in the same collision domain

All devices in the same  broadcast domain

Devices share the same handwidth

*Switch and Bridges Operate at Data Link

Each segment has its own collision domain

All sements are jin the same broadcast domain

*Router

 each interface has its own collision domain and broadcast domain

   %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

双绞线 UTP 非屏蔽 常用  ，STP

同轴电缆

光纤： 单模光纤 以激光作为光源，仅有一条通路 传输距离长

          多模光纤  由发光二极管提供光源 低速距离短

 ￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥￥

 An Overview of Cisco Device Startup

*Find and check device hardware

*Find and load Cisco IOS Software image

*Find and apply device configurations