#CATOS SHOW MAC ADDRESS TABLE MAC#

Routers can also be configured to bridge packets. The default mode is typically store-and-forward on Cisco switches. Although cut-through switching is faster, the switch could potentially forward frames with errors, because the CRC is not checked. The CRC is checked to ensure that frames containing errors or CRCs are not forwarded. Store-and-forward switching occurs when the entire frame is received before forwarding the frame. This technique is known as adaptive cut-through. If a switch in cut-through mode encounters a large number of frames with CRCs, it drops down to store-and-forward mode.

#CATOS SHOW MAC ADDRESS TABLE MAC#

Cut-through switching occurs when, after the destination MAC address is received, the switch immediately forwards the frame to the outgoing port. NOTE Transparent bridges can operate in two traditional modes. Frames that are received as broadcasts are sent out all ports active in spanning tree. The switch then adds the source MAC address on the source port. Any broadcasts (packets sent by a host that are destined for all hosts in the same broadcast domain) received because the switch has no CAM entry are sent out all ports except the port the frame was received on. When a device first sends a frame to a connected port on a switch, the switch adds the incoming source address to the CAM table. Chapter 8, 'CCIE Security Self-Study Lab,' displays CAM tables of the newest form of Cisco IOS-based switches so that you have exposure to both operating systems.ДЄ Cisco switch populates the CAM tables as new devices send frames, so a switch bases all bridging decisions on the source MAC address.

The CCIE Security exams test on both Cisco CatOS and Cisco IOS. NOTE The examples in this chapter display the traditional Cisco CatOS operating system. Example 1-1 displays that the MAC address 01-10-7b-54-37-c6 is located via the port 8/13. You can use other CatOS commands to view specific ports (show cam dynamic 8/13 would show only devices discovered on port 8/13). VLAN Dest MAC/Route Des Destination Ports or VCs / Д®xample 1-1 displays a CAM table on a Catalyst switch with the CatOS command show cam dynamic. Show cam show cam show cam agingtime show cam mlsrp CAT5513 (enable) show cam dynamic Example 1-1 displays a sample CAM table on a Cisco Catalyst 5000 switch.Д®xample 1-1 CAM Table or Bridge Table CAT5513 (enable) show cam ?

Switches build CAM tables when activity is noted on switch ports. Routers use Layer 3 switching to route packets, and Layer 2 switches use Layer 2 switching to forward frames. Source stations are discovered and placed in a switch address table (called a content-addressable memory table in Cisco terms). Switching, or bridging, is defined as a process of taking an incoming frame from one interface and delivering it through another interface. The terms switch and bridge are used to refer to the same technology. This section covers Layer 2 devices that are used to bridge, or switch, frames using common techniques to improve network utilization, such as VLANs.

Catos show mac address table