Working Principles of the Layer 2 switch & Layer 3 switch | Network Administration

 Working Principles of the Layer 2 switch & Layer 3 manage switch  | Network Administration.

• Switches are Layer 2 device,
• Routers are Layer 3 device
• The new generation of Layer 3 switches route using hardware only.
• A switch will examine the incoming frame's MAC header to determine the physical address of the destination device.
• Whereas a HUB , simply repeats an incoming frame out of all its ports, the switch creates a virtual path to forward frames to the port. Where it knows the destination device exist.
• Switch can provide flow control to network traffic by temporarily storing frames in a buffer. 
• Switch can also generate BACK PRESSURE to cause transmitting device to wait long enough for the switch to deal with backlogged traffic. To create back pressure, the switch broadcast false collation detection signals to cause network interface card to back off.
  

 

Do's and Don'ts of Structured LAN Cabling Network

 What is Structured Cabling & Why it is used ?

"Standard " is to define a method of connecting all types of vendors voice & data equipment, over a cabling system that uses a common media, common connectors and a common topology. This means that a building can be cabled for all its communications needs without the planner or architecture even having to know what type of equipment will be used.

There are three main cabling standards.

• EIA/TIA 568 A ---> American standard and was the first to be published on 1991.
• ISO/IEC 11801 ---> International Standard.
• CENELEC EN 50173 ---> European Standard (British version is BSEN 50173) .

TERMS:

1. Cable Tie
2. Patch Panel
3. PVC pipe of Casing
4. IO Box
5. RJ45 connectors
6. Cat 5e/6/7 cable
7. Wall mount Box.

Password Recovery ASA 5520

Password Recovery Process for Cisco ASA 5520.

1. Reboot Power
2. When prompted , press Esc to interrupt the boot process and enter ROM monitor mode.You should see a Rommon Prompt (rommon#0> ).
3. rommon#0>confreg (press enter).
4. current configure register should be default of 0x01. Device will ask if you want to make changes to the configuration register.
   Answer : NO
5. You must change the configuration Register to 0x41.
6. rommon#1>confreg 0x41
7. Reset the device.
8. rommon#2> boot
9. Now after booting you will see a general user mode like. ciscoasa>
10. ciscoasa> enable password
11. ciscoasa#
12. ciscoasa#copy startup-config running-config
13. ciscoasa#config t
14. ciscoasa(config)#enable password
15. Reset the configuration to default value 0x01.
16. ciscoasa(config)#config-register 0x01
17. View the configuration register setup
18. ciscoasa#show run startup-config
19. reload
20. ciscoasa#reload
21. System config has been modified,save [Yes][No]
22. press Yes.
    

Show Broadcast Packets

Show Broadcast Packets on CISCO Manage Switches

It is very important for Network Admin to monitor broadcast packets in his Network. Here I mention some very basic cisco manage switch command for monitoring network packets.

1. #sh int fa 0/1 count
2. #sh int counters
   
3. #sh int counters trunk
4. #sh int count errors
5. #sh int count protocols status
6. #sh int valn 1
7. #sh flow control
8. #sh storm control broadcast
   

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