ccna 200-301 network simulator ns21 streaming

ccna 200-301 network simulator ns21 streaming.00-1B-24-7D-25-05 00-11-BC-7D-25^04 195.1.1.2 193.1.1.2 23 1030 Telnet^ according to CRC checkFigure 2-6-5 Format of Data Frames Sent by Router R2 Data frames encapsulated at the data link layer are passed to the physical layer and converted into a bit stream in binary form to be sent out of Router R2's Fa0/0 interface. Step 5: The bitstream from router R2 arrives at the switch (note that the icon in Figure 2-6.1 indicates the switch), which, in addition to amplifying the bitstream, learns it based on the source MAC address and forwards it based on the destination MAC address. The switch queries the MAC address table based on the destination MAC address in the data frame and sends the bitstream out the corresponding port. the switch sends the bitstream to the server and not to PC3. step 6: The server receives this bitstream, converts the bitstream into frame format, and uploads it to the data link layer. the server finds that the destination MAC address in the data frame is the same as the MAC address of this NIC. The server removes the encapsulation of the data link layer and uploads the packet to the network layer. The network layer of the server compares the destination IP address in the packet and finds that it is the same as the IP address of the local machine. the server removes the encapsulation of the network layer and uploads the data segment to the transport layer. The transport layer acknowledges, sequences, and reorganizes the data segments to ensure the reliability of the data transmission. The data is finally passed to the server's application layer. The whole packet flow process from PC1 to Server is shown in Figure 2-6-6, from which it can be seen that PC1 performs the encapsulation of OSI seven layers and then passes the bit stream to the hub; the hub simply amplifies the signal at the physical layer and then passes the bit stream to router Rl; R1 performs the processing of the next three layers of OSI and then passes the bit stream to router R2; R2 performs the processing of the next three layers of OSI and then passes the bit stream to router Rl; R2 performs the processing of the next three layers of OSI Layer 3 processing and then pass the bitstream to the switch; the switch performs Layer 2 processing under OSI and then pass the bitstream to the server. From this flow process, it can be found that the data stream is mainly performed on the intermediate devices at the lower three layers of OSI, and the devices at the physical layer do not change the format of the frames and broadcast forwarding: the devices at the data link layer also do not change the format of the frames, but can forward them according to the destination MAC address in the data frames.Devices at the network layer change the format of the frame, to perform the decapsulation and re-encapsulation of the frame, but do not change the source and destination IP addresses in the packet.Step 7 = The server receives a Telnet packet from PC1 and responds to PC1. Similar to the process handled by PC1, the server knows that it is sending to a remote network and that the destination MAC address at the data link layer needs to encapsulate the gateway's47JHub R1 R2 SwitchFigure 2-6-6 Encapsulation and DecapsulationfCCNA Study and Lab Guide .MAC address; the network layer source and destination IP addresses are the opposite of the packets sent from PC1, that is, the source address becomes the destination address,and the destination address becomes the source address; the transport layer source and destination ports are the opposite of the packets sent from PC1, that is, the source port becomes the destination port and the destination port becomes the source port. The format of the data frame sent back by the server is shown in Figure 2-6-7.Frame Header Network Layer Header Transport Layer Header Data According to Frame End Destination Source Destination IP Source IP Destination Port Source Port Ah"