Networking and the Internet Layered Approach

Networking and the Internet Layered Approach to Internet Software III Dr. M. Tanvir Afzal  Layered Approach to Internet Software III Network Layer When packet is received, it uses forwarding table to send the packet. H...

Networking and the Internet Layered Approach to Internet Software III Dr. M. Tanvir Afzal  Layered Approach to Internet Software III Network Layer When packet is received, it uses forwarding table to send the packet. Hands-in the packet to Link layer. Link layer then process the packet to its destination 2  Layered Approach to Internet Software III Link Layer If the network is Ethernet, it uses CSMA/CD If its wifi, it uses CSMA/CA. When the packet is received to link layer of other side, it send to network layer. 3  Layered Approach to Internet Software III Network Layer At each step, packets final destination is compared with forwarding table details. Network layer gives back the packet to link layer. These two layers are only involved in intermediate steps so forming the core of routers. 4  Layered Approach to Internet Software III Network Layer Routers can forward the packet in millisecond. Network layer recognizes when the packet reaches to its final destination. Packet is then handed over to transport layer which assembles the original message and hands over to application layer. 5  Layered Approach to Internet Software III Port Numbers Determining which unit within the application layer should receive an incoming message is an important task of the transport layer. This is handled by assigning unique (port numbers) 6  Layered Approach to Internet Software III Accepted Port Numbers Browser contacts HTTP server at port # 80. Similarly SMTP clients knows to contact application layers at server at port # 25 7  Summary Layered Approach to Internet Software III Network Layer. Link Layer. Ports 8