It is a smarter (newer version) of Hubs
It is also called a Multiport Bridge
It can memorize MAC (Media Access Control) Address of all the devices connected using MAC Address Table (Mapping of Switch Port to MAC Address)
As switches know the MAC Address of all devices connected to it the traffic is contained to the ports that are actually participating in the communication
Switch performs three actions: Learning, Flooding and Forwarding
Switch MAC Address Learning
Each port on the switch forms its own Collision Domain, but all the ports are part of the same Broadcast Domain
L2 switches cannot route data between VLANs
Switches have a MAC Address and IP Address but for any traffic that is going through them this details are not required
They only come in handy if we need to connect to the Switch to perform maintenance
Link Aggregation
Part of the IEEE 802.3ad standard
Allows to combine multiple physical connections into a single logical connection
Used to increase the bandwidth of uplink (LAN to WAN) connection
Power over Ethernet (PoE)
Part of PoE 802.3ad and PoE+ 802.3at standards
Allows to supply power over Ethernet cables
Requires CAT 5 or higher copper cable
Each cable can provide up to 15. 4 Watts (PoE) or up to 25.5 Watts (PoE+)
Port Monitoring (Mirroring)
Makes a copy of all traffic destined for one port to another port
User Authentication
Part of the 802.1x standard
Require users to authenticate before gaining access to the network
Management Access
SSH: Remote Administration
Console Port: Local Administration using rollover cable (DB-9 one end and RJ-45 on another)
OOB (Out-of-Band) Management: Keep all network configuration devices on a separate network
MAC Filtering
Permit or deny traffic based on the MAC Address of devices
Quality of Service (QoS)
Forward packets based on priority markings