cisco ccna new

cisco ccna new.Protocol (IP).O However, the model covers much more than these two protocols; it also defines a layered approach that can be used for almost anyIt also defines a layered approach that corresponds to almost any of the protocols used in today's communication networks.As originally defined, the TCP/IP model has four layers, each of which provides transport and other services to its overlying layers. These four layers are the link layer, the Internet layer, the transport layer, and the application layer.According to the latest definition of the TCP/IP model, the link layer is further divided into two sub-layers to clearly distinguish between the physical class or data link class of services and protocols included in this layer. The Internet layer is sometimes referred to as the network layer, and the network layer gets its name from another very well-known model, the SI reference model, which is described in the next section. The TCP/IP protocol stack model is shown in Figure 1-1.Figure 1.1 TCP/IP protocol stack model1.2 TCP/IP and. SI Reference Model 5Tortoise In terms of how it works, the TCP/IP model is grounded in two main concepts involving how the layers interact with each other, as shown under the I point. Within the same host, the layers of the TCP/IP stack interact in such a way that the lower layer provides its own upper layerservices. Between different hosts, the same layer uses the same protocol to communicate.