This is my 1st presentation on 24/07/2009 at 3 pm with cik Marina.

3 way handshake

The three-way handshake in Transmission Control Protocol - TCP (also called the three message handshake) is the method used to establish and tear down network connections. This handshaking technique is referred to as the 3-way handshake or as "SYN-SYN-ACK" (or more accurately SYN, SYN-ACK, ACK).

• SYN = Synchronize
• ACK = Acknowledge

The TCP handshaking mechanism is designed so that two computers attempting to communicate can negotiate the parameters of the network connection before beginning communication. This process is also designed so that both ends can initiate and negotiate separate connections at the same time.

Host A sends a TCP SYNchronize packet to Host B

Host B receives A's SYN

Host B sends a SYN-ACK

Host A receives B's SYN-ACK

Host A sends ACK

Host B receives ACK. TCP connection is ESTABLISHED

what is jumbo frame???

Ethernet has used 1500 byte frame sizes since it was created (around 1980). To maintain backward compatibility, 100 Mbps ethernet used the same size, and today "standard" gigabit ethernet is also using 1500 byte frames. This is so a packet to/from any combination of 10/100/1000 Mbps ethernet devices can be handled without any layer two fragmentation or reassembly.

"Jumbo frames" extends ethernet to 9000 bytes. Why 9000? First because ethernet uses a 32 bit CRC that loses its effectiveness above about 12000 bytes. And secondly, 9000 was large enough to carry an 8 KB application datagram (e.g. NFS) plus packet header overhead. Is 9000 bytes enough? It's a lot better than 1500, but for pure performance reasons there is little reason to stop there. At 64 KB we reach the limit of an IPv4 datagram, while IPv6 allows for packets up to 4 GB in size. For ethernet however, the 32 bit CRC limit is hard to change, so don't expect to see ethernet frame sizes above 9000 bytes anytime soon.