ccna wireshark

ccna wireshark.One problem this may cause is that when PC.B sends an ARP reply back to PC.A, both switches may happen to have PC-A's MAC addressB to PC.A, both switches may have associated PC-A's MAC address to port 2, and therefore assume that PC.A is in segment 2, and thus discard the ARP reply instead of forwarding it. This results in PC.A not receiving an answer to its ARP request and cannot communicate with PC-B. Of course, PC-A can perform the ARP request again, but this only adds insult to injury: it causes the number of frames circulating in the loop to increase from 2 to 4!13.1.3 Command showprocessesIOS devices have different architectures, but all use two switching methods when processing packets: process switching and Cisco Express Forwarding (CEF) switching, the latter of which is performed by an application-specific integrated circuit (ASIC). an ASIC is a specialized processor that allows a device to execute a very small instruction set at a very fast speed. an ASIC is similar to a graphics processing unit (GPU) that performs graphics functions , but performs networking functions and is used to process traffic in the device. Cisco products may have one or more ASICso when processing traffic and deciding where it should be forwarded, the first packet must usually be processed by the CPU: a lookup of the MAC address in the CAM table (for switches) or the destination IP address in the routing table (for routing devices). Once this information is known, it can then be stored in the ASIC's cache, allowing the ASIC to process subsequent frames or packets in the stream based on this information, thus reducing the burden on the CPU.In addition to creating the ASIC cache, the CPU must also process other management protocol information, such as spanning tree information, routing protocol information, Cisco Discovery Protocol (CDP) frames, VLAN Trunking Protocol (VTP) frames, Dynamic Trunking Protocol (DTP) frames, and regular traffic sent to its IP address, such as broadcast or unicast management protocols like Telnet, SNMP, SSH packets. If the CPU needs to handle too much management traffic, the IOS device will be overwhelmed.The command show processes displays the current running processes of the IOS device, and this information can help determine whether the IOS device is running properly. The following is sample output from this command.Switch# show processesCPUutilization forfive seconds: 21%/0%; one minute: 2%; five minutes:2%PIDQTy PCRuntime(ms) Invoked uSecs StacksTTYProcess1 Cwe 606E9FCC 0 1 05600/6000 0ChunkManager