Layer 2 Switching
1. Layer 2 device
2. works on Data link layer
3. It forwards frames on the basis of MAC addredd
4. it has single broadcast domain an multiple collision domain
- Learning source MAC address
- Forwarding and filtering Layer 2 data
- Loop avoidance
- Switch performs 2 Table CAM/MAC address table and TCAM table
MAC address Table:-
||Type of Learning
- MAC address table has aging time of 300 sec i.e 5 minute and after every 5 minutes switch refreshes it self and MAC address will erase
because host are connected to Switch mainly and host can change time to time.
- Dynamic entry will erase after aging time but static enrty do not erase.
- When switch receives data it learns MAC address and saved to MAC address table is called Dynamic and MAC address can be stored manually and
is called Static.
See MAC address use command #Show mac-address-table
- Entering MAC manually in switch
switch(config)#mac-address-table static A vlan 1 interface f0/0
Here A ia MAC addredd of device
Vlan is the Vlan of that particular interface host is connected
Interface f0/0 is interface
number that host is connected.
- Increasing aging time
switch(config)# mac-address-table aging time [? - time]
The number of MAc learning on s single switch depends upon storage capability of the catalyst/Switch.
Switch has a 2 types of ports:-
1. Access port:
The access port on switch are ports which are connects to end devices or hosts.
Configuring access port :
switch(config)#switchport mode access
2. Trunk Port:
The trunk port on switch are ports which are connects to another switch.
Configuring trunk port :
switch(config)#switchport mode trunk
Different Between Access POrt and Trunk Port
|Member of Single Vlan
||All Vlan member
|Forwards single Vlan traffic
||Forwards all Vlan traffic
|Traffics are untagged
||Traffics are tagged
|DTP is disabled
||DTP is enable
|No encapsulation is not done
||Encapsulation is done
Above while learning difference between access and trunk port you got to know that encapsulation is done in trunk port.
There are two way of encapsulation of trunk port.
|It adds extra 30 bytes information into frame
||It adds only 4 bytes of information on ethernet header
|26 byts is header and 4 byte is trailer, header contains vlan info
||4 byte info contains vlan info
|Doesnot support Native Vlan
||Does support Native Vlan