On last Friday we talked about some protocols of the IP Architecture and how it had evolved on the last years.

At first, we spoke about the IP protocol. The IP level is too complex and there are so much protocols to manage, and because of this is really difficult to change or update at the IPv6. Also the appearance of IPv6 created new problems, i.e. applications that were using the IP addresses as user identifier have to change at the new 8 addresses.

We also talked about the Transport Control Protocol (TCP), which at first was oriented at non-reliable communications, low link speed and short distances, but has expanded and nowadays is almost the unique protocol used on the transport layer. It consists of the creation of a virtual circuit where all the packets travel, and with a Round Trip Time (RTT) and the Congestion Avoidance Algorithm to control the saturation of the net. Because of this, the network performance depends on the effectiveness of the TCP protocol.

The BGP protocol allows us to exchange routing information and is one of the most important protocols because it stabilizes the net and gives scalability, although it hasn’t been analytic proved.

We also spoke about three other protocols: NAT, IPSEC and MPLS. Those protocols violate the end-to-end principle but are completely necessary to the net. The NAT protocols is responsible of the translation of the addresses between public and private, and has avoided the exhaustion of the IPv4. It is also a first protection of the corporate network. The IPSEC protocol provides us an end-to-end encryption and hides the transport protocols to the ISP. The MPLS protocol is designed to unify the data transport service on circuit commutation networks and packet commutation networks.