ccna certification uses

ccna certification uses.Forwarding: Forwarding means that when a computer sends a data frame to the switch, the switch checks the destination MAC address of the frame, and whenWhen there is a corresponding table entry in the MAC address table, the received data frame is forwarded out from the corresponding port.5Filtering: In some cases, frames will not be forwarded, a process called frame filtering. The conditions of use for filtering were described earlier: the switch does not forward incoming data frames to the port where they were received. In addition, the switch discards corrupted frames, e.g., frames that do not pass the Cyclic Redundancy Check (CRC) are discarded.7.1.2 Switch Forwarding MethodsThere are three methods for Ethernet switches to forward data frames as follows..90 . Cisco Networking Lab CCNA Lab Guide (Release 2)1. store ( Store-and.Forward) forwardingThe store-and-forward method is a receive-and-forward method. It receives and caches all the data frames received from the switch port, then performs CRC checks and discards the wrong frames (for example, if it is too short, less than 64 bytes, or too long, greater than 1518 bytes, or if there is an error during data transmission, it will be discarded), and finally retrieves the source and destination addresses of the data frames, looks up the MAC address table, and then filters and forwards them. The delay of store-and-forward method is proportional to the length of data frame, the longer the data frame is, the more time it takes to receive the whole data frame, so the delay is bigger, which is its shortcoming. But it can perform high level error detection on the packets entering the switch. This method can support switching between ports of different speeds and maintain the cooperation between high-speed ports and low-speed ports.2.Through ( Cut.Through) Forwarding