Switch - Intro
- switches operate at Data Link Layer 22 - Data Link Layerof the OSI model
- a switch is a multi-input, multi-output (MIMO) device (i.e. transfers packets from an input to one or more outputs)
- switches identifies 2 things:
- a way to identify the host address:
- Ethernet 48-bit MAC address (addresses are assumed to be a globally unique identifier)
- a way to identify port:
- by number
- by name
- a way to identify the host address:
- switches contain:
- forwarding table
- tells switch how to forward a packet
- used in Datagram scheme
- virtual table
- tells switch how to forward a packet
- used in Virtual Circuit scheme
- forwarding table
Switch - Types
|
Switch Type |
Managed Switches |
Unmanaged Switches |
|---|---|---|
|
Features |
Dynamic ARP Inspection, IPv4 DHCP snooping, QoS, SNMP, VLAN, CLI, IP routing, port mirroring, redundancy, etc. |
Fixed configuration—doesn’t support any configuration interface or options |
|
Performance |
Switch can be configured Control over Access Control over LAN traffic—Priority SNMP—Allows for remote troubleshooting of the network |
Plug and play with limited configurations like default QoS settings |
|
Security |
Very good. Provide protection of the data plane, control plane, and management plane |
Not very good. No security other than accessories such as a lockable port cover |
|
Costs |
Expensive |
Less expensive |
|
Application Places |
Data centers, large-size enterprise networks |
Small-size business network, home, lab, conference rooms, etc. |