how to check mac address table in cisco router

Each dynamically learned MAC address is associated with one and only one switch port. In the above output, you should be able to identify various dynamically learned MAC addresses and the switch ports those MAC addresses are associated with. Total Mac Addresses for this criterion: 27 The command show mac address-table, not surprisingly, is used to display the MAC address table of a switch we just talked about, as shown below: In this way, a switch dynamically builds an address table by using the source MAC address of the frames received.Īs a practice, try issuing command ipconfig /all on Windows CLI and show mac address-table on Cisco switch CLI to get warmed up for later examples. When the switch receives a frame, it associates the MAC address of the sending device with the switch port on which it was received. The switch maintains an address table called MAC address table in order to efficiently switch frames between interfaces. The term packet is used to describe the layer 3 header and data without the layer 2 header or trailer. The term frame refers to the bits and bytes that include the layer 2 header and trailer along with the data encapsulated by the header and trailer. Let’s make a distinction between frame and packet before moving forward as these terms are often used rather loosely. They are merely different representations of the same MAC address. A Microsoft Windows system would list a MAC address as 12-34-56-78-9A-BC whereas a Cisco switch would list it as 1234.5678.9abc. Ethernet addresses, also known as MAC (Media Access Control) addresses, are 6 bytes or 48 bits in length, typically written in hexadecimal form. The ultimate goal of switches is to carry frames from the source to the appropriate destination based on the destination Ethernet address in the frame header.

How to check mac address table in cisco router