1. Layer 2 switches break up large collision domains into smaller ones by making each switch port its own collision domain, allowing a more efficient Ethernet LAN network than with hubs. 2. Bridges and switches learn MAC addresses and their associated ports by reading the source MAC address of each received frame and recording the port on which the MAC address was received. 3. The Spanning Tree Protocol provides a loop-free redundant network topology by placing certain switch ports in the blocking state and identifying one switch as the root bridge using BPDUs.

1. 1Presentation OnSwitchingPresented by :-Ashish Kushwah7th semesterRoll No.0928ec081007

2. Layer 2 SwitchingSwitching breaks up large collision domains into smaller ones

3. Collision domain is a network segment with two or more devices sharing the same bandwidth.

4. A hub network is a typical example of this type of technology

5. Each port on a switch is actually its own collision domain, you can make a much better Ethernet LAN network just by replacing your hubs with switches2

6. How Switches and BridgesLearn Addresses3Bridges and switches learn in the following ways: Reading the source MAC address of each received frame or datagram

7. Recording the port on which the MAC address was received. In this way, the bridge or switch learns which addresses belong to the devices connected to each port.

8. Ethernet Access with Hubs4

9. Ethernet Access with Switches5

10. Switch FeaturesThere are three conditions in which a switch will flood a frame out on all ports except to the port on which the frame came in, as follows:

11. Unknown unicast address

12. Broadcast frame

13. Multicast frame6

14. MAC Address Table7Initial MAC address table is empty.Learning Addresses8Station A sends a frame to station C.

15. Switch caches the MAC address of station A to port E0 by learning the source address of data frames.

16. The frame from station A to station C is flooded out to all ports except port E0 (unknown unicasts are flooded).Learning Addresses (Cont.)9Station D sends a frame to station C.

17. Switch caches the MAC address of station D to port E3 by learning the source address of data frames.

18. The frame from station D to station C is flooded out to all ports except port E3 (unknown unicasts are flooded).Filtering Frames10Station A sends a frame to station C.

19. Destination is known; frame is not flooded.11Spanning Tree Protocol

20. Spanning-Tree Protocol12Provides a loop-free redundant network topology by placing certain ports in the blocking state.Spanning Tree Protocol13Spanning Tree Protocol resides in Data link Layer

21. Ethernet bridges and switches can implement the IEEE 802.1D Spanning-Tree Protocol and use the spanning-tree algorithm to construct a loop free network. Spanning-Tree Port States14Spanning-tree transits each port through several different states:Disabled

22. Selecting the Root Bridge15The first decision that all switches in the network make, is to identify the root bridge.

23. When a switch is turned on, the spanning-tree algorithm is used to identify the root bridge. BPDUs are sent out with the Bridge ID (BID).

24. The BID consists of a bridge priority that defaults to 32768 and the switch base MAC address.

25. When a switch first starts up, it assumes it is the root switch and sends BPDUs. These BPDUs contain BID.

26. All bridges see these and decide that the bridge with the smallest BID value will be the root bridge.

27. A network administrator may want to influence the decision by setting the switch priority to a smaller value than the default.16Switch Configuration

28. Switch Command Modes17Switches have several command modes.

29. The default mode is User EXEC mode, which ends in a greater-than character (>).

30. The commands available in User EXEC mode are limited to those that change terminal settings, perform basic tests, and display system information.

31. The enable command is used to change from User EXEC mode to Privileged EXEC mode, which ends in a pound-sign character (#).

32. The configure command allows other command modes to be accessed. Switch ConfigurationThere are two reasons to set the IP address information on the switch:

33. To manage the switch via Telnet or other management software

34. To configure the switch with different VLANs and other network functions

35. See the default IP configuration = show IP commandConfigure IP Addresssw1(config-if)#interface vlan 1sw1(config-if)#ip address 10.0.0.1 255.0.0.0sw1(config-if)#no shutsw1(config-if)#exitsw1(config)ip default-gateway 10.0.0.25418

36. Configuring Interface DescriptionsYou can administratively set a name for each interface on the switchesSW1#config tEnter configuration commands, one per line. End with CNTL/ZSW1(config)#int e0/1SW1(config-if)#description Finance_VLANSW1(config-if)#int f0/26SW1(config-if)#description trunk_to_Building_4SW1(config-if)#Setting Port SecuritySw1(config-if)#switchport port-security mac-address mac-addressNow only this one MAC address is allowed on this switch port19

37. 20VLANs

38. VLAN Overview21Segmentation

39. Flexibility

40. SecurityA VLAN = A Broadcast Domain = Logical Network (Subnet)

41. VLAN Membership Modes22

42. VTP Protocol FeaturesA messaging system that advertises VLAN configuration information

43. Maintains VLAN configuration consistency throughout a common administrative domain

44. Sends advertisements on trunk ports onlyVTP Modes24Creates VLANs

45. Modifies VLANs

46. Deletes VLANs

47. Sends/forwards advertisements

48. Synchronizes

49. Saved in NVRAM

50. Creates VLANs

51. Modifies VLANs

52. Deletes VLANs

53. Forwards advertisements

54. Does not synchronize

55. Saved in NVRAM

56. Forwards advertisements

57. Synchronizes

58. Not saved in NVRAMTHANKS…….