NET-02 · Educational simulation

ARP & MAC Address Resolution

PC-A knows PC-B’s IP address but not its MAC. Watch the broadcast flood the LAN, the single reply come back, the tables learn — and then the first real frame cross.

1ARP Request

2Flood

3ARP Reply

4Resolved

5Ethernet frame

ARP Request (broadcast)
ARP Reply (unicast)
Ethernet frame

React Flow

ReadyStep 0 / 20

PC-A wants to send a frame to 192.168.10.12 but does not know its MAC address. Press “Start ARP”.

Speed

Explanation

Before you start

PC-A knows PC-B’s IP address, but an Ethernet frame needs a MAC address. Press “Start ARP” to watch how it finds out, or “Step” to advance one stage at a time.

Why did the PC send a broadcast?
Keep going — the answer unlocks when the run reaches it.
Why does the switch flood the ARP request?
Keep going — the answer unlocks when the run reaches it.
Why does only the correct IP respond?
Keep going — the answer unlocks when the run reaches it.
How does the PC learn the MAC?
Keep going — the answer unlocks when the run reaches it.
How does the switch learn MACs?
Keep going — the answer unlocks when the run reaches it.

Message inspector

No message yet

Type: —
Operation: —
Sender IP: —
Sender MAC: —
Target IP: —
Target MAC: —
Ethernet destination: —
Broadcast / unicast: —
EtherType: —
Current device: —
Current port: —
Status: Ready

Device

PC-A

Role: Sender — needs a MAC address
IP: 192.168.10.11 / 24
MAC: 00:1A:2B:3C:4D:0A
Switch port: Fa0/1
ARP cache: empty
Doing now: Idle

Event timeline

0 / 20

ARP cache lookup--:--:--
ARP Request created--:--:--
Broadcast sent--:--:--
Switch received--:--:--
MAC Table updated--:--:--
Broadcast forwarded--:--:--
Target received--:--:--
Non-target discarded--:--:--
ARP Reply created--:--:--
Reply sent--:--:--
MAC Table updated--:--:--
Reply forwarded--:--:--
Reply delivered--:--:--
Reply received--:--:--
ARP Cache updated--:--:--
Ethernet frame ready--:--:--
Ethernet frame sent--:--:--
Frame switched--:--:--
Frame to PC-B--:--:--
Frame delivered--:--:--

Address tables

What the devices have learned

PC-A ARP cache

IP address	MAC address	State	Age
Empty — PC-A knows no MAC addresses

SW-01 MAC address tableaging 300 s

MAC address	Port	VLAN	Type	Learned
Empty — the switch has not seen a frame yet