A switch builds its MAC address table by recording the MAC address of each device connected to each of its ports.
#SHOW MAC ADDRESS TABLE TRAFFIC CURENT HOW TO#
LAN switches determine how to handle incoming data frames by maintaining the MAC address table. CAM is a special type of memory used in high-speed searching applications. As the switch learns the relationship of ports to devices, it builds a table called a MAC address table, or content addressable memory (CAM) table. For a switch to know which port to use to transmit a frame, it must first learn which devices exist on each port.
#SHOW MAC ADDRESS TABLE TRAFFIC CURENT SOFTWARE#
A switch is made up of integrated circuits and accompanying software that controls the data paths through the switch. Switches use MAC addresses to direct network communications through the switch to the appropriate outbound port toward the destination. Dynamically Populating a Switch MAC Address Table (1.2.1.2) With a LAN switch, there is only one master switching table that describes a strict association between addresses and ports therefore, a message with a given destination address always exits the same egress port, regardless of the ingress port it enters.Ĭisco LAN switches forward Ethernet frames based on the destination MAC address of the frames. The only intelligence of the LAN switch is its capability to use its table to forward traffic based on the ingress port and the destination address of a message. If a message enters switch port 3 and has a destination address of AB, then the switch forwards the traffic out port 6.If a message enters switch port 5 and has a destination address of EE, then the switch forwards the traffic out port 1.If a message enters switch port 1 and has a destination address of EA, then the switch forwards the traffic out port 4.
Go to the course online to see an animation of how a switch forwards a frame based on the destination MAC address. When a switch makes a decision, it is based on the ingress port and the destination address of the message.Ī LAN switch maintains a table that it uses to determine how to forward traffic through the switch.Īctivity 1.2.1.1: LAN Switch Forwarding Operation The term egress is used to describe frames leaving the device through a particular port. The term ingress is used to describe a frame entering a device on a specific port. The decision on how a switch forwards traffic is made in relation to the flow of that traffic. The fundamental concept of switching refers to a device making a decision based on two criteria: Various types of switches are used in LANs, WANs, and the public switched telephone network (PSTN). The concept of switching and forwarding frames is universal in networking and telecommunications. Switching as a General Concept in Networking and Telecommunications (1.2.1.1) Switches receive a frame from the source device and quickly forward it toward the destination device. On Ethernet networks, frames contain a source MAC address and a destination MAC address. Learning how switches operate is important to someone entering the networking profession. This keeps the table to a workable size.One of the most exciting functions of networking is the switched environment because businesses are always adding devices to the wired network, and they will do so through a switch. Enter the number of days you want entries to remain in the table.Įach time the activity runs, the existing MAC address table entries that are older than the expiration period are removed. This may be useful if you have some devices not yet supported in the CatTools default device list.Īctivates associated numeric field. Set an alternate command if the default command issued by CatTools does not produce the correct results. Activity optionsĬonfigure the options specific to this activity in the Options tab. Setting up the activity for Report.MAC address tableįor information on setting up activities, see Add / Edit scheduled activity details. Entering an alternate command to use overrides all default commands. Optionally, you to use an alternate command and to set the expiry date of MAC entries in the report. CatTools gathers information from every command that succeeds and ignores any command that does not produce a valid result. In these cases, not every command issued is valid for every device selected. The default location of this file is \Reports\Master MAC address table.txt.īy default, this activity may issue more than one command depending on the device type. The Report.MAC address table activity gathers MAC address entries (CAM table entries) from switches and bridging routers and can builds a table over time.
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