Layer 2 / Layer 3 IP Packets Switching Procedures

Layer 2 Packets Switching Procedures

The packet will be sent in the same vlan.

1. A sends ARP -who is 10.1.1.3?
Destination MAC address : ALL FF's
Source MAC address: A1

2. ARP is broadcast so switch forwards out all ports

3. B replies to ARP
Destination MAC:A1
Source MAC: B1

4. A sends to B
Destination MAC: B1
Source MAC: A1
Destination IP address: 10.1.1.3
Souce IP: 10.1.1.2

5. Switch performs CAM lookup using destination mac address and forwards packet to B1.



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Layer 2 / Layer3 IP Switching Procedures

Packets will send from A to D across multiple vlans:

1. A sends ARP - who is 10.5.1.2?

Destination MAC address : ALL FF's
Source MAC address: A1

2. Switch replies to ARP - saying send it to me

3. A sends to Switch

Destination MAC: C1

Source MAC: A1

Destination IP: 10.5.1.2

Souce IP: 10.1.1.2

4.Switch does a L3 lookup 

5. Packet forwarded

Destination MAC: D1

Souce MAC: C3

Destination IP: 10.5.1.2

Source IP:10.1.1.2

6. Switch does a forwarding lookup

7: Packet forwarded

Destination MAC: F2

Source MAC: D2

Destination IP: 10.5.1.2

Souce IP: 10.1.1.2