CyberCertPrepSecurity FundamentalsNetworking FundamentalsEASYFree question
What is the fundamental difference between a switch and a router?
- A.Switches work at Layer 3
- B.Routers only work with wireless, since a router decides where to forward a packet by consulting its ARP cache rather than the routing table, and when no cache entry exists it broadcasts the packet out of every interface until a neighbouring router returns an acknowledgement naming the correct next hop
- C.A switch operates at Layer 2 and forwards frames based on MAC addresses within a local network, while a router operates at Layer 3 and forwards packets based on IP addresses between different networks - switches connect devices on the same network, routers connect different networks together
- D.Switches and routers are the same device, because switching happens at layer 3 and routing at layer 2, which is why a switch has to run a routing protocol to populate its forwarding table while a router builds its own table by flooding unknown frames out of every interface until a reply identifies the correct outbound port
Why C is correct
Switch: Layer 2, uses MAC address table, forwards frames within LAN, creates separate collision domains. Router: Layer 3, uses routing table, forwards packets between networks, creates separate broadcast domains. Layer 3 switches can do both. Understanding helps with network architecture analysis.
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