CCNA learning: Cisco Device Manage

CDP: Cisco Discovery Protocol

Used to connect switcher,router and other devices

Physical device support SNAP(Subnetwork Access Protocol)

Information: Device ID, Local Interface, Holdtime, Capability, Platform, Port ID

Command

1. Start to use CDP for device: cdp run

2. Stop to use CDP for device: no cdp run

3. Start to use CDP for interface serial 0:

interface serial0

cdp enable

4. Stop to use CDP for interface serial 0:

interface serial0

no cdp enable

5. Check neighbor information: sh cdp neighbors

6. Check neighbor detail information: sh cdp entry

7. Check flow volumn: sh cdp traffic

8. Check device interface: sh cdp interface

9. Remote login: telnet <IP Address>

(If the device allow telnet, it will show information)

Return back to source device: <Ctrl+Shift+6>x

Return back to target device: resume 1 or enter twice

Source device close telnet command: disconnect

Target device close telnet command: clear line <session id>

10. Check session(this device has login which devices): sh session

11. Check user(Which devices login to this device): sh user

12. Check connection: ping / trace

13. Check NVRAM number: show version

configuration register is:......

14. Check Flash: show flash

15. Check configration file in RAM: show running-config

16. Check configuration file in NVRAM: show startup-config 

Router Start Process

NVRAM number: 16 bits

1. POST

2. Load and execute microcode (check NVRAM number first 4 number)

0 1 2 3: boot sequence

0000: ROM monitor

0001: Mini ISO

0010 - 1111: Check bootsystem command in configuration file, exist follow command, otherwise search ISO image file in flash

default: 0010

3. Search IOS image file (save in flash)

4. IOS image file exists, Load IOS image file.

Otherwise check IOS from internet. Load IOS file from internet successfully, next step.

Load from internet failed. check NVRAM number 13

The number of 13 is 1: Check the number of internet search fail time is 5.  after that, use Mini ISO

The number of 13 is 0: Check the number of internet search fail time no limit. 

Default number of 13 is 1

5. Load IOS into memory. Search configuration file, check NVRAM number 6

The number of 6 is 1: start to setup dialog(forget the password)

The number of 6 is 0: Next step 

6. Verify the configration file. Verfiy failed, start to setup dialog. Otherwise start

Router Hardware

RAM: router memory

ROM: BIOS, clock, POST, ROM monitor(error detection for IOS system), Mini IOS

Flash: router harddisk save IOS(router operation system)

NVRAM: configuration file

Router file management

Configration file:

RAM --> NVRAM: copy running startup (after config)

NVRAM --> RAM: copy startup running

TFTP --> RAM: copy tftp running

RAM --> TFTP: copy running tftp (backup config)

TFTP --> NVRAM: copy tftp startup

NVRAM --> TFTP: copy startup tftp

Delete  configuration file(NVRAM): erase start

IOS image file:

1. confirm router and server connection;

2. confirm the free space of server

3. check IOS file name: show flash (*.bin)

4. backup: copy flash tftp

recover or upgrade: copy tftp flash