Using a too large (even if its default) arp timeout means that the dist-router. Introduction CAM (Content Addressable Memory) VERSUS TCAM (Ternary Content Addressable Memory) CAM VS TCAM Multilayer switches forward structures and product at wiring speed by using ASIC hardware. The switch stores the MAC information in a table called the CAM table or the MAC table. R1 wants to communicate with Host A. The ports are restricted and learn up to a maximum of 10 dynamically-learned addresses D. If the frame contains a Layer 3 packet to be forwarded, the destination MAC address is that of a Layer 3 port on the switch. Look a cut-through switch receives and examines only the first 6 bytes of a frame, which carries the DMAC address. This is called MAC flooding. Reply. The CAM is used with other functions to analyze and forward packets very quickly. The user wanting to. Switches keep a table of Ethernet MAC addresses called a CAM Table or a Bridge forwarding table. Share. There’s not much to see here yet, though, since we haven’t hooked anything up to the switch yet. CAM Table B. H vlan 1 interface fastEthernet x/y. CAM is most useful for building tables that search on exact matches such as MAC address tables. An exception is an ARP entry for an interface-based static IP route that goes to a destination that is one or more. If you use this command just after turning on the switch, it displays a blank CAM table. On a Cisco switch you can view the CAM table (MAC address table) by issuing the "show mac address-table" command. If a MAC address learned on one switch port has. I just know that cam contain mac address, port and vlan information. More about CAM over flow: CAM overflow. Specials Layer 2 and Layer 3 components, such as routing tables or Access Control Lists (ACLs), been stockpiled int. Switching table is a Layer 2 table while the Routing Table is a Layer 3 table. If you specify an address but do not specify an interf ace, the address is deleted from all. Cisco uses the terms MAC address table and CAM table interchangeably. . 1. We are having an issue during automatic or manual failover where the MAC addresses for the virtual-servers are not being updated. CAM Table. To avoid having duplicate CAM table entries during that time, a switch purges any existing entries for a MAC address that has just been learned on a different switch port. 0/8 NW is connected on xx i/f. The logical ip address related entries, the next device c will help traffic from the lab purposes and keeping the table and cam mac address la entre. 9. Forwarding information base. All Catalyst switch models use a Content Addressable Memory (CAM) table for Layer 2 switching. The ARP table is a result of an ARP request after the ARP reply is received. Topic #: 1. Ran show mac address-table on different switches and core itself (on the core, for example, plugged by desktop directly, my desktop ), and we can see the several different MAC hardware address being registered to the interface, even. In this case, the CAM table results are used only to decide that the frame should be processed at Layer 3. 1 Answer. The CAM overflow attack exploits the fact that a switch is not able to add any new entry to its CAM table, and therefore fallbacks into "behaving like a hub" (as it is often described, I'll come back on this later). When a frame reaches into the port of a switch, the switch reads the MAC address of the source device from frame and compare it to its MAC address table (also known as CAM (Content Addressable Memory) table). Cisco switches perform MAC address table lookups with CAM memory exact match. C. 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. Limiting the number of registered MAC addresses on a switch access port can help prevent a CAM table overflow attack. Attackers exploit the MAC flooding technique to make a switch and act as a hub, allowing them to easily sniff traffic. MAC flooding topics are discussed to illustrate why network switches will act like a hub. The memory operation is performed with a single operation instead of per entry. This could lead to a man-in-the-middle-attack. Something most people don’t realize is that there is a limited amount of MAC addresses that a network switch can store in its MAC address table, and this can be exploited. 36d0 vlan 1 interface fastEthernet 0/1. MAC address table, also known as Content Addressable Memory (CAM) table is a table that switches use to forward packets at layer 2. The mac address table is a table maintained in a finite amount of memory. •Configure Port Security to mitigate these. The interface where we learned the MAC address. if conditions a) and b) happen there is an uniknown unicast flooding, but as soon as the intended destination MAC address answers back the CAM entry is created again and unknown unicast flloding stops for that MAC address . ago MartianPacket. X. •Switch is then in Fail-Open mode and broadcasts all frames, allowing the attacker to capture those frames. Mitigation. CAM Table的全名是Content-addressable Memory Table，也就是大家所熟知的Mac table，主要是用於二層的網路通訊. The CAM table is empty until ingress traffic arrives at each port B. It is also known as associative memory or associative storage and compares input search data against a table of stored data, and returns the address of matching data. But CAM tables on BOTH switches don't contain this MAC entry! I know that if we see flooding only on one side one would conclude that the. If the flag is unset, delete the MAC address from the table. It is used to fill up switch'es CAM table with bogus MAC addresses, so it can't learn any new legitimate MAC addresses and starts flooding packets, allowing attackers to sniff traffic on a switch. 123. As a workaround, you can issue one of these commands in order to increase the CAM aging timer for the VLAN you are having trouble with to match the ARP aging time: For CatOS, issue the set cam agingtime command. I'm using "show mac-address-table" and "show ARP. The MAC address table supports partial matches. The CPU will take a closer look at the membership report and will create an entry in the CAM table: In the CAM table above you can see an entry for MAC address 0100. CAM Table Overflow/Media Access Control (MAC) Attack. Switching in CAM: In multilayer switching, CAM is used for the purpose of switching frames to their destination. Accordingly, a. X. Switch's MAC address table has only a limited amount of memory. CLN member. The RAM is a temporary. Contributor In response to Elliot Dierksen. There are three types of address; unicast, multicast and broadcast. Published in. STEP2-. The "show arp" command shows the IP, corresponding MAC and the corresponding Router Interface also. Beginner Options 11-15-2020 09:41 AM - edited 11-23-2021 02:17 PM Any network connection is a logical connection between two endpoints. However, MAC refers to the contents, and CAM the type of memory. Recall that a CAM table takes in an index or key value (usually a MAC address) and looks up the resulting value (usually a switch port or VLAN ID). 1. 璿的筆記. MAC address filtering involves configuring a MAC address switch to only accept packets from known MAC addresses. If you're a little confused on what CAM, TCAM, and FIB tables are I'll give you a short rundown. It is a specialized version of CAM depicted for quick table lookups. The cam table of the switch know pc 1 and pc2. You can start a new thread to share your ideas or ask questions. Link. The switch sends out a frame to all forwarding ports within the respective VLAN when the destination MAC address is aged out from the CAM table. The invalid MAC addresses are flooded into the source table. CAM is used to build routing tables. Depending on what your issue is and what you are attempting to accomplish it may be advisable to clear one or the other, or even perhaps both. Look at the switch port shown in the entry and move to the neighboring switch connected to that port. From the command line, issue the appropriate command: CatOS devices: show cam dynamic. To get a better idea of how the MAC addresses are stored within the CAM table, we'll use the following network topology to demonstrate:This feature allows you to set the MAC Address Table configuration. A MAC address table, sometimes called a Content Addressable Memory (CAM) table, is used on Ethernet switches to determine where to forward traffic on a LAN. All Catalyst switch models use a Content Addressable Memory (CAM) table for Layer 2 switching. Ya that should be the case ideally. In the case of Layer 2 switching tables, the switch must find an exact match to a destination MAC address or the switch floods the packet out all ports in the VLAN. تفاوت جدول MAC و جدول CAM در سویچ چیست؟. It has to do this for every port. . 4. . When a frame is received, the switch compares the SOURCE MAC address to the MAC address table. Switch(config. - After ARP for DGW, it will learn the MAC of DGW and will forward that PING packet to router(I have skipped the point that switch is also in MAC learning phase & is updating his CAM table). As soon as the user tries to ping host. Hello experts, When looking about mac address table on a 3750E I'm getting a different output between the following commands. MAC C. . Unicast media access control (MAC) addresses are learned to avoid flooding the packets to all the ports in a VLAN. The MAC Address is a unique identifier that identifies every network interface on a network. A switch can learn MAC address in two ways; statically or dynamically. 1/ sh platform tcam utilization : The unicast mac addresses row shows me more than 3K unicast mac addresses used on the 6K available with the default sdm. Hope this helps. That is normal behavior for the CAM table. CAM address C. It will flood it out all ports except the receiving port of the frame. All endpoints are stored as objects of the class fvCEp. json (you'll need to filter out the corresponding leaf). CAM Table Stores:Ethernet addresses, also known as MAC (Media Access Control) addresses, are 6 bytes or 48 bits in length, typically written in hexadecimal form. Nowadays CAM is more and more replaced by faster. در سوییچ جدولی تحت عنوان MAC/CAM table وجود دارد که اطلاعات Mac address پورت های متصل به سوییچ در آن وجود دارد و ارسال packet ها درون شبکه را با استفاده از این table انجام میدهدMLS. TCAM memory does not require the ASIC to execute loops through an algorithm to search the table. prefer more space for routes or MAC addresses or ACLs). 2. z router. 5 - A receives the ARP response and now knows all the. 2 Answers Sorted by: 14 MAC Table (Layer 2) The MAC table is used by the switch to map MAC Addresses to a specific interface on the switch. So there is no need for a MAC Table I guess. MAC addresses are used by network switches to keep track of what devices are connected to each switch interface and they store these mappings in a table called a CAM table or MAC address table. The MAC address table resides in content addressable memory (CAM). Bravo. When there is no matching entry in the MAC table, switches flood the frame out all interface/ports except the incoming interface or the one on which the frame was received. The reason why it also floods it out port 1-12 even though it has a mac-port mapping on all these ports are because a new client may have appeared behind one of. CAM Table Overflows occur when an influx of MAC addresses are flooded into the table and the CAM table threshold is reached. It is composed of the IP address and its MAC ADDRESS. Second, the ASIC needs to perform table lookup in the MAC address table, so for fast table lookup, the switch uses a specialized type of memory to store the equivalent of the MAC address table: ternary content-addressable memory (TCAM). The Adjacency table records IP address and Layer 2 header for the IP and then references the TCAM table and at this point the switch will have enough information to rewrite the packets headers and send them out the egress port. Content addressable memory) maintained by the switch, and if there is. When you enable CAM table usage monitoring, the number of valid entries in the CAM table are counted and if the percentage of the CAM utilization is higher or equal to the specified threshold, a message is displayed. Edited by Admin February 16, 2020 at 5:05 AM. This fills in the switch’s CAM table, thus new MAC addresses can not be saved, and the switch starts to send all packets to all ports, so it starts to act as a hub, and thus we can monitor all traffic passing through it. Reply to A's IP address will get wrapped in the wrong. The switching table entries are normally dynamically. ARP is used by a layer-3 device (host, router, etc. Links:NX-OS: Default mac-address timeout: 30 min (1800 secs) Default arp timeout: 25 min (1500 secs) with the following note: The ARP timeout should be less than the MAC address table aging timer, so the ARP updates prevent entries from timing out of the MAC address table. So considerable number of incoming frames will be flooded at all ports. Cuando se utiliza TCAM - Ternary Content Addressable Memory dentro de los routers L3, se utiliza para realizar una búsqueda de direcciones más rápida que permita un enrutamiento rápido. a. It is built by the switch as the switch processes. CAM (Content Addressable Memory) is specialised hardware that's used to store the MAC address table. It is used for Layer 2 frame forwarding and ARP tables. It suggests that some switches "do not allow spoofing of ARP packets". then what about TCAM, 1. The layer-2 and layer-3 functions in a layer-3 switch are completely. There’s not much to see here yet, though, since we haven’t hooked anything up to the. CAM Table B. sh mac address-table dyna int g0/1. To form the base for subsequent sections, this section includes a brief understanding of the switch‘s CAM table. The CAM table is the primary table used to make Layer 2 forwarding decisions. ARP table is the table that holds binding between a certain IP address and corresponding MAC address. By default, MAC address learning is enabled on all interfaces and VLANs on the router. Switches will automatically populate the CAM table from framers that pass through the switch. In computer networking, a media access control attack or MAC flooding is a technique employed to compromise the security of network switches. You can configure Layer 2 MAC address and VLAN learning and forwarding properties in support of Layer 2 bridging. The destination MAC address is used as an index to the CAM table. Mark as New;- [Instructor] The CAM or MAC address table on a switch maps the MAC address of a device to tne physical switch port. And then you have to look at the refresh and timeout for each table but generally dynamic ARP entries expire earlier to prevent them from becoming stale, causing conflicts when a device moves and/or wasting space. As of STP steps , it learns from which ports a mac-address arrives and populates its CAM TABLE( mac-address/port). The SW6's MAC table contains the SW7 interfaces' MAC addresses. By implementing router prefix lookup in TCAM, we are. If the DMAC is not known in the CAM table, the switch will flood it. how will be the lookup process in L3 switches. Sorted by: 4. Introduction CAM (Content Addressable Memory) VS TCAM (Ternary Content Addressable Memory) CAM VS TCAM Multilayer switches forward frames and packets at wire speed by using ASIC hardware. Switching doesn't know anything about layer-3, and that allows a switch to carry any layer-3 protocol. MAC Address Tables. It is composed of the IP address and its MAC ADDRESS. D. 2. Larger CAM tables like 32K are more standard for enterprise and some larger distribution switches will allow for 64K or higher. VIDEO 14 in the GNS3 Labs for CCNA 200-301. 1. . The router has a single table (CAM - content addressable memory) where it stores things like MAC address associations. -However you will get arp for the configured IP. CAM - Content Addressable Memory: This table holds all of the MAC address information the switch has. The "Macof" tool is used to fill CAM table of target switch in few seconds. Switch. derek. Yes, this it still is a threat and this is why: MAC flooding is based on the overflow of the CAM Table (Content Access Memory). B. The ARP table is a result of an ARP request after the ARP reply is received. The CAM can store MAC table and many other kinds of data - it is not limited to pure MAC addresses. The FTD 1010 connects to a switch which runs back to our core to our FMC management system. z. The MAC address table consists of two types of entries. As mentioned earlier, MAC addresses are Layer 2 addresses that operate at the Data Link -Layer 2 of the OSI model. Each CAM table lookup is based on a hash key associated with a destination MAC address and VLAN ID. The data frames are sent over the network. A switch can learn MAC addresses in two ways; statically or dynamically. The source MAC address is not in in the switch's Content Addressable Memory (CAM) table. 4567. Configure aging time by entering a value in seconds. ARP entry exists: 192. This makes the switch think that these are real mac address connections, with their corresponding ports, and use these to fill up the CAM table. Dynamic entries are automatically erased after being present in the table for a certain period of time (specified by the command mac-address-table age-time). MAC table holds the information of where a device is connected in a switch of a LAN , It answers the question : In what port of a switch is connected device with MAC address ? Cheers ! Ismael Mariano. CAM is most useful for building tables that search on exact matches such as MAC address tables. C. X. This guide will use the term CAM table moving forward. Switches dynamically learn MAC addresses of each connecting CAM table. 6. In switches CAM – Content Addressable Memory is used for building and lookup of mac address table that enables L2 forwarding decisions. ·. Now applying this to networking devices, when looking up an address in the MAC address table, you always require an exact match, so CAM is used. 2. Case 1: Local. MAC, routing, security, and QoS scalability numbers depend on the type template used in the switch. Dispute regarding CAM vs TCAM. g. 361. If, after 300 seconds, no other frame is detected on that port, the MAC is removed from the CAM table. Switch then acts as a hub by broadcasting packets to all machines on the network and attackers can sniff the traffic easily. Click the card to flip 👆. It tells the switch which port to forward frames given a specific MAC address. The mac-address-table is used by the switch for layer 2 forwarding. For Cisco IOS software, issue the mac-address-table aging-time command. شرح حمله CAM-Table overflow. prefer more space for routes or MAC addresses or ACLs). 4900M#show mac address-table count MAC Entries for all vlans: Dynamic Unicast Address Count: 8507 Static Unicast Address (User-defined) Count: 130 Static Unicast Address (System-defined) Count: 18 Total Unicast MAC Addresses In Use: 8655 Total Unicast MAC Addresses Available:. The MAC address table is where the switch stores information about the other Ethernet interfaces to which it is connected on a network. Every switch has a pool of mac-addreses for internal allocation for its processes. 12. The problem that I am suggesting does not have anything to do with ports 1 or 2 talking to ports 3 or 4. Host A and host B are in a different network. 9abc. A MAC address table is used by a layer-2 switch to relate the layer-2 address to the switch interface. Content Addressable Memory (CAM) Table Overflow is a Layer 2 attack on a switch. Network monitoring. Set timeouts for entries in the dynamic MAC Table and configure the static MAC table here. X/Y IP destination, go through z. e. Total Mac Addresses : 3Total Mac Addresses for this criterion: 5. Attackers exploit the MAC flooding technique to make a switch and act as a hub, allowing them to easily sniff traffic. The Adjacency table records IP address and Layer 2 header for the IP and then references the TCAM table and at this point the switch will have enough information to rewrite the packets headers and send them out the egress port. To build the CAM table or make entries in the CAM table, the switch uses the source MAC address field of the incoming frames. Looking at the output of "sh cam dynamic x/x" the listed 'destination port' for the addresses is the switch access port the devices are connected to, thats a given. this video, Keith Barker covers CAM table overflow attacks. TCAM is also a fast cached memory table however it is used primarily for routing table. Routing table is a L3 table which states for X. 4. ·. The CAM table has a limited size and if you manage to exceed that size the switch isn't able anymore to assign new MAC addresses to a physical port. CAM is Content Addressable Memory. The port of arrival and the VLAN are both recorded in the table, along with a timestamp. CAM. Switch(config)# mac address-table static H. 168. The frame is sent out the corresponding switch port. By implementing router prefix lookup in TCAM, we are moving process of. is the broadcast frame sent as a broadcast due to the ARP destenation. Because the destination is not known, the switch forwards the frame out to all ports except the port through which the frame arrived. [All 350-401 Questions] What is the difference between the MAC address table and TCAM? A. You can control MAC address learning on an interface or VLAN to manage the available MAC address table space by controlling which interfaces or VLANs can learn MAC addresses. Reading the Official Certification Guide, and Foundation Learning Guide, I was led to believe that CAM was used for the layer 2 forwarding table (CAM Table, aka Mac Address-table) and that TCAM was used for functions like QoS and Security ACL's. the traffic [4]. Something most people don’t realize is that there is a limited amount of MAC addresses that a network switch can store in its MAC address table, and this can be exploited. z. A sends packet to X with correct IP source address but incorrect source MAC address. But it's added as a static entry in the CAM. Selected as Best Selected as Best Like Liked Unlike Reply. 1. Here's why: MAC address tables (sometimes referred. TCAM stands for Ternary Content Addressable Memory. Routing Table D. z. A switch has one cam table for all vlans. A switch learns unicast MAC addresses into its source address table or CAM table by inspecting each frame's source address. Figure 3-6 displays the typical CAM table population by a Cisco switch. Cuidado: o comando mac-address-table synchronize apaga as entradas MAC roteadas. Routing template is not supported in the LAN Base feature set. Now the switch cannot deliver the incoming data to the destination system. 0 Helpful Reply. The CAM table is also known as MAC forward table, MAC filter table, MAC address table, switching table, or bridging table. 1 / 18. MAC aging time can be configured in either interface configuration mode or in VLAN configuration mode. Managed switches store the MAC addresses of devices in a special location called the CAM table. The CAM table (Content Addressable Memory) records the source MAC address, port & VLAN, and timestamp of each received frame. Use the command to configure how long entries remain in the Ethernet switching table before expiring. This type of attack lets an attacker exploit the hardware and memory limitations of a switch. Given a Cisco 3750, I can do a. Here to help. We will do simple ping from R1 to SW1 and see the MAC table on SW1 as below: R1#ping 9. The very process of finding the root of the spanning tree is enough. They are merely different representations of the same MAC address. - CAM table (or MAC table) was stored in DRAM of routers (or switches) This is not a precise statement. For IPv6 hosts, see NDP Table. That physical machine has two nics teamed and they trunk to this Cisco 3750. The CAM table is divided into "instances" that store the MAC addresses of the different VLANs. . On most network devices, the command is either. the arp timeout is longer than the mac-address-timeout. This specialised data structure makes it possible. It is a dynamic table that maps MAC addresses to. It has ARP table mapping ip address to mac -address. Switches need build a structure called MAC-ADDRESS TABLE ( also CAM TABLE) to be able to forward the frames between its ports. Unless, of course, there was no activity from PC2 for five minutes and the MAC address was flushed from the CAM table but PC1 still has a valid entry in its ARP cache because four hours has not passed yet (default MAC and ARP. It performs the entire search operation in a single clock cycle. . What is a Routing Table? 3. To add entries into the CAM table, set the aging time for the CAM table, and configure traffic filtering from and to a specific host, use the set cam. چند روز پیش یکی از کاربران توسینسو از من در خصوص تفاوت بین MAC Table یا جدول آدرس های سخت افزاری شبکه و همچنین تفاوت آن با CAM Table یا جدول حافظه. The MAC address table is stored in fast volatile memory, allowing lookups to be performed very quickly. Table lookup is fast and always based on an exact key match consisting of two input values: 0 and 1 bits. Apr 27, 2021. 7. This is a part from that book. with default timers this means that that MAC address has been silent for more then 300 seconds (CAM aging time) and less then for 4 hours (ARP timeout), it is not a problem itself it can be an effect and not a cause. 2. 2. Details set cam. Study with Quizlet and memorize flashcards containing terms like 1. Introduction CAM (Content Addressable Memory) VS TCAM (Ternary Content Addressable Memory) CAM VS TCAM Multilayer switches forward frames and packets at wire speed by using ASIC hardware. X. 4 Kudos. The mac-address-table static mac-address vlan vlan-id interface int disable-snooping command disables snooping on the. Use the mac address-table static command to create a static entry. Generally to find the IP address associated to a MAC Address, the easiest way is to look in the ARP tables. The CAM table shows which port the frame must be sent out in order for that frame to reach the specified destination MAC address. If the SOURCE is unknown, the switch adds it to the table along with the physical port number the frame was received on. z router. forwarded frame, it updates the CAM table with the port on which the communication was received. Most Voted. TCAM memory does not require the ASIC to execute loops through an algorithm to search the table. But I have a physical machine hosting some vms. For any matching results, CAM will return the destination port (the associated content). MAC Table C. The CAM table, or content addressable memory table, is present in all Cisco Catalysts for layer 2 switching. This is surprising to me, and it really threw me off when I was playing with port-security (the maximum number of MAC addresses was reached, which triggered a violation, and I could not figure. I checked by logging into the Router. What is Switch MAC Table (CAM Table)? 2. In switches, CAM tables store the MAC addresses for different devices on its ports. What is difference between cam table and mac table?Finally the command you would use to verify the maximum MAC addresses a switch would allocate in its CAM table is sh mac address-table count or sh mac-address-table count. The entry recorded into the CAM table includes the port number, the frame arrived on, and the source MAC address associated with the frame, and also the timestamp for the frame's arrival. When the table is full then it is full for every vlan. For example, if you have 1000 devices connected. Layer-2 switches don't care about layer-3 or layer-3 addresses, so they don't use ARP, but they do care about which. In no case does a properly working switch associate multiple ports with the same MAC. This guide will use the term CAM table moving forward. What is an ARP Tab. Here the VLAN is. The MAC Learning Process described below; STEP1-. 2. . A MAC flooding attack is noisy and can be easily detected by checking the switch's CAM table and discovering a large number of MAC addresses associated with an access port (Figure 1). The ARP table is built from the replies to the ARP requests, recorded before a packet is sent on the network. When using TCAM – Ternary Content Addressable Memory inside routers it’s used for faster address lookup that enables fast routing. z router, send packets to Mac Address aa:bb:cc:dd:ee:ff. When downstream switches from the Root start receiving the BPDUs with the Topology Change (TC) bit set to 1, it will reduce the CAM tables aging timer from the default 300s to the current FWD_DELAY time (15s default). New addresses will then be learned. It is a Layer 3 to Layer 2 mapping. Flapping MAC address is more often an indication of a layer 2 loop, rather than an attack. If no entry exists, it will add the MAC of Host A plus the port to which Host A is connected to its CAM table. 04-28-2015 12:44 AM. Otherwise, the CAM table entry for the end station will time out before the ARP entry times out, meaning that the FHRP device knows (from its ARP cache) the MAC address corresponding to the destination IP address, and therefore does not need to ARP for the MAC address. show arp. ARP table = layer 3. The CAM table is also known as MAC forward table, MAC filter table, MAC address table, switching table, or bridging table. Here’s what the MAC address table looks like now: SW1#show mac address-table static | include Fa0. In the case of Layer 2 switching tables, the switch must find an exact match to a destination MAC address or the switch floods the packet out all ports in the VLAN. The CAM table provides a binary result for any query of 0 for true or 1 for false. Content Addressable Memory (CAM) table is a system memory construct used by Ethernet switch logic which stores information such as MAC addresses available on physical ports with their associated VLAN Parameters. But if we're sending packets with bogus MAC addresses (even with a specified IP address), the packets are still spoofed. PC A wants to communicate with PC B, such as sending a message. The switch takes care of the incoming frame source MAC address and enters it into the CAM table and stays there at 300 seconds before aging out. I need to find out what port a MAC address is connected to. 255 (IP for layer 3 broadcasts). This is possible as the tool sends huge amount of MAC entries per minute. Switches uses an extension of a CAM, known as the TCAM or Ternary Content Addressable Memory. This flood of data causes the switch to dump the valid addresses it has in its CAM database tables in an attempt to make room for the bogus. Disabling MAC Address Learning on an Interface or VLAN.