ccna question

ccna question.It can provide reliable or unreliable data transmission; it divides data into smaller, more manageable segments; it can provide data through ready/notready signals or windowing techniques using sequence numbers and acknowledgements to control traffic and thus avoid congestion; it uses buffers to store incoming dataTCP and UDP are both protocols that run at the transport layer.The network layer defines logical addresses, finds the best path to the destination logical address by using the routing table on the router, and connects different types of Layer 2 links. Let's not forget the benefits offered by routers, such as through the use of hierarchical network design and routingprotocols to provide scalability, limit the propagation of broadcasts, and intelligently select paths, QoS, and traffic filtering.The data link layer defines how devices connect to the Layer 2 medium and how devices communicate with each other using physical addresses, such as MAC addresses in Ethernet. Be sure to know what a MAC address looks like: it is 48 bits long and is expressed in hexadecimal.Encapsulation and UnpackingBe familiar with the PDU terminology used at each layer of the OSI reference model: data segment (transport layer), packet or datagram (network layer), frame (data link layer), and bit (physical layer). Also, be sure to be able to describe how devices communicate with each other at each layer: what Layer 2 and Layer 3 addresses are used between the various devices from the source and destination ° Don't forget that MAC addresses may change as data travels from one link to another, but Layer 3 addresses (such as TCP/IP addresses) usually remain the same.2.4 Authentication SummaryThe OSI reference model defines how to connect the two network functional layers. The application layer provides the user interface; the representation layer determines how data is presented to the user; the session layer is responsible for establishing and dismantling connections; the transport layer is responsible for implementing the connectivity mechanisms, including guaranteed services; the network layer provides the logical topology and layer 3 addresses, and routers run at this layer; the data link layer defines MAC addresses and how to communicate over specific media types, and switches, bridges, and NICs all The physical layer defines the physical characteristics of connections and communications, and transponders and hubs all run at this layer. Wireless solutions are defined at the physical layer.