![mac address flooding mac address flooding](https://wiki.wireshark.org/uploads/__moin_import__/attachments/CaptureSetup/Ethernet/Capture-switch-hub-ws.png)
We will start by looking at the individual switch functions, and then take a look at an animation which shows their collaborative operation. It might be worth reviewing that section before proceeding. This article will be the practical application of everything that was discussed when we looked at a Switch as a key player in packet traveling. We will take a look at what happens for communication from Host to Host through a Switch.
![mac address flooding mac address flooding](https://www.ciscozine.com/wp-content/uploads/Asymmetric-routing-in-depth-4.png)
In this article, we will add a common network device: a switch. In the last article, we looked at everything that happens for two hosts to communicate directly with one another. Use the navigation boxes to view the rest of the articles. Switch.This article is a part of a series on Packet Traveling - everything that happens in order to get a packet from here to there. A broadcast frame, by definition, will always be flooded by a In summary, a Broadcast is a frame addressed to everyone on the local network (), and Flooding is an action a switch can
MAC ADDRESS FLOODING MAC
As such, any frame destined to this MAC address will always be Reserved, the switch is unable to learn a MAC Address Table mappingįor it. (after learning the Source MAC, of course).Īnother way of looking at it is, since the address is Reserved for the purpose of broadcasting.īy definition, if the Switch ever encounters a packet with aĭestination MAC of, it will always flood the frame This is done using the same Ethernet header we’ve beenĭiscussing, except the Destination MAC address field is populated withĪ special address:. Understandable because the end result is the same, but it is alsoĪ Broadcast frame is a frame which is addressed to everyone on the There is often some confusion about a switch in regards to a Broadcast and a Switch’s flooding behavior. In broadcasting the host that created the frame itself addressed the frame to everyone.
MAC ADDRESS FLOODING HOW TO
In flooding the switch sends the frame to all because it doesn't know how to reach the destination. When the switch receives a broadcast frame, it sends it out to everyone connected to it. Usually the host creates this type of frames during the ARP process. A frame becomes a broadcast frame if the destination mac address is ffffffffffff. The switch doesn't change any header data in the frame.Īll the devices that receive the frame will compare the destination mac address in the frame with their own mac address and drops the frame if it doesn't match.Ī broadcast frame is created by the host itself. The frame is still a unicast frame, since it has a specific destination mac address in its header. If there is no entry for the destination mac in its table, it will simply send the frame out to everyone connected to it's ports.
![mac address flooding mac address flooding](https://techhub.hpe.com/eginfolib/networking/docs/switches/5980/5200-3908_evpn_cg/content/images/image12.png)
When a switch receives a unicast frame(a frame with a specific mac address intended for a particular device), it looks for the frame's destination mac in its mac-address table. I will explain here in the context of switches(Layer 2)
MAC ADDRESS FLOODING FULL
Each OSPF router needs to have a full understanding of all the routers and routes in its area, and it tells all its neighbors about all its local routes, and any routes it hears about from other neighbors. OSPF doesn't use broadcasts to send routes, it uses unicast or multicast to connect with its neighbors. It really has nothing to do with a broadcast. This, too, is limited to a broadcast domain.įlooding in OSPF (layer-3) means that the routes get delivered to every OSPF router in an area. If a frame is not destined for a host which receives it, the host will ignore it and not be interrupted. A broadcast cannot cross a layer-3 device, and every host in a broadcast domain must be interrupted and inspect a broadcast.įlooding is used by a switch at layer-2 to send unknown unicast frames to all other interfaces. Broadcasts are sent to a special broadcast address, both for layer-2 and layer-3. Broadcasting is a term that is used on a broadcast domain, which is bounded by layer-3 (routers).