Link. The MAC address table is stored in fast volatile memory, allowing lookups to be performed very quickly. What is an ARP Tab. z router, send packets to Mac Address aa:bb:cc:dd:ee:ff. The MAC address table, sometimes called a MAC Forwarding Table or Forwarding Database (FDB), holds information on the physical switch port a specific device is connected to. 01c then it looks that MAC address up in the CAM table. Failopen mode: the switch starts behaving as a hub and broadcasts the incoming traffic through all the ports in the network. Then, repeat the CAM table process. The MAC Address is a unique identifier that identifies every network interface on a network. 1D standards on a per-instance which follows the same rules. I'm using "show mac-address-table" and "show ARP. The "show arp" command shows the IP, corresponding MAC and the corresponding Router Interface also. This allowsARP cache table. Static and sticky secure addresses will also be put into the running-config. For this type of entry, the MAC address. As soon as the user tries to ping host. The MAC address table resides in content addressable memory (CAM). What happens next? A new entry is added to the CAM table, mapping the source device's MAC address to the port on which the frame was received. STEP2-. تفاوت جدول MAC و جدول CAM در سویچ چیست؟. MAC flooding topics are discussed to illustrate why network switches will act like a hub. Only ports which have the device connected and active will show the. All Catalyst switch models use a Content Addressable Memory (CAM) table for Layer 2 switching. You can start a new thread to share your ideas or ask questions. VIDEO 14 in the GNS3 Labs for CCNA 200-301. It's easy to get them mixed up, as they have similar names. Bravo. Sorted by: 4. If the flag is unset, delete the MAC address from the table. MAC addresses (layer 2) and routing tables (layer 3) are not related at all. The command to look it up in almost all switches/devices is show mac-address table (or some form of this). 2. The maximum default time an entry will be kept on the table is 300. In computer networking, a media access control attack or MAC flooding is a technique employed to compromise the security of network switches. 6. A hub forwards all packets to all ports. 1D will set the MAC aging timer to the FWD_DELAY timer and 802. Usually there should not be any interruption. . B. In a switched network, each device (e. CAM specifies a special type of memory (you can address it by using the "thing" you're looking for as an address), so a FIB could be implemented in CAM (but doesn't have to). We would like to show you a description here but the site won’t allow us. NB: Switches populate the cam table by looking at the source mac-address only. MAC address table, also known as Content Addressable Memory (CAM) table is a table that switches use to forward packets at layer 2. If you use this command just after turning on the switch, it displays a blank CAM table. Packets that are sent on the Ethernet are always. It is composed of the IP address and its MAC ADDRESS. you are asking about ARP tables, and you're using OID . After you finish, optionally do a clear mac address-table to accelerate healing from potentially full CAM table. 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. But when I issue the "show mac address-table" command, the switch only shows the usual "STATIC CPU" addresses, and not the DYNAMIC ones, which are those of the SW7's interfaces. Macof can flood a switch with random MAC addresses. Because the destination is not known, the switch forwards the frame out to all ports except the port through which the frame arrived. In the case of Layer 2. A MAC Address Table (MAT), also known as a Content Addressable Memory (CAM) table, is a database stored in a network switch that lists the MAC addresses of all the devices connected to the switch. Click the card to flip 👆. TCAM is used to make L2 forwarding decisions. 9. Hope this helps. Well, the sticky option will put the learned MAC into CAM table as 'static', then the port security config will keep track of other mac addresses on configured port and take configured action with 'violation error' if wrong MAC address is detected. PC A wants to communicate with PC B, such as sending a message. For IPv6 hosts, see NDP Table. 4. If you have two networks, each with 100 devices on them, then the router has to learn, or remember, up to 200 MAC addresses. The "show arp" command shows the IP, corresponding MAC and the corresponding Router Interface also. CAM Table. This could lead to a man-in-the-middle-attack. PC A : MAC Address a. NB: Switches populate the cam table by looking at the source mac-address only. Cisco IOS uses multiple techniques for L3 routing a packet in software: (1) process switching (2) fast switching and (3) CEF switching. Also, many switch platforms support either syntax. 1. Here to help. 1. This is a part from that book. The CAM can store MAC table and many other kinds of data - it is not limited to pure MAC addresses. However, if the CAM Key Topic 10/24/14 entry has timed out, the. Vendor explains this based on some configuration MAC/ARP table settings on the network devices the firewall attach to. Hence it would be wrong to think that if Switches flush out the cam entry even routers do. What do routers reference in order to make packet forwarding decisions? A. MAC Address Table . This switch is responsible for keeping track of which device is connected to each port by maintaining a table called the “MAC Address Table”, which. what it contains, 2. Next steps. 璿的筆記. Specific Film 2 and Covering 3 components, such as routing tables otherwise Access Control Lists (ACLs), belong. 4. ARP Table (Layer 3) The ARP table is used to map MAC Addresses. 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. MAC aging time can be configured in either interface configuration mode or in VLAN configuration mode. Look a cut-through switch receives and examines only the first 6 bytes of a frame, which carries the DMAC address. On the switchAs expected I see the end host(PC), plus IP phone MAC in the CAM table as a dynamic entry. R2#show arp. - CAM table (or MAC table) was stored in DRAM of routers (or switches) This is not a precise statement. 4. CAM stands for Content Addressable Memory. An Ethernet switch in a switched network contains a CAM table that holds all of the MAC addresses of devices in the network. -However you will get arp for the configured IP. CAM address C. 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. Hi everyone. However, MAC refers to the contents, and CAM the type of memory. In an Ethernet switch, there is likely only one CAM table--the MAC table, so the terms have become somewhat interchangeable. the CAM table is the table where the associations MAC address, Vlan, port are stored. Command Modes Privileged EXEC (#) Command History Usage Guidelines If the clear mac address-table command is invoked with no options, all dynamic addresses are removed. 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. It requires a minimum number of secure MAC. And the network might go haywire. 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. Session stealing. The source MAC address is not in in the switch's Content Addressable Memory (CAM) table. 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. For Cisco IOS software, issue the mac-address-table aging-time command. 3. ARP spoofing | ARP poisoningFor visibility of mac-address binded on NIC cards. 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. The CAM table is divided into "instances" that store the MAC addresses of the different VLANs. X/Y IP destination, go through z. The switch adds a device MAC address in the CAM table only when it receives a frame from that device on any of its port. Larger CAM tables like 32K are more standard for enterprise and some larger distribution switches will allow for 64K or higher. As of STP steps , it learns from which ports a mac-address arrives and populates its CAM TABLE( mac-address/port). MAC Address Table is full and it is unable to save new MAC addresses. تفاوت Cam Table و Mac Table. Cisco IOS uses multiple techniques for L3 routing a packet in software: (1) process switching (2) fast switching and (3) CEF switching. 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. If the. . Hello experts, When looking about mac address table on a 3750E I'm getting a different output between the following commands. Forwarding table is a Layer 2 table which states for communicating with z. This command displays the real-time entries of the CAM table. Any packets with a source MAC address that is not on the approved list will not be saved to the forwarding table. Known details: PC A -> SW 1 -> Router -> SW 2 -> PC B. For example, if you have 1000 devices. In this case, the CAM table results are used only to decide that the frame should be processed at Layer 3. derek. The MAC Learning Process described below; STEP1-. The ARP timeout deals with the amount of time an ARP (layer-3 to layer-2 address resolution) entry remains in the ARP table before it is aged away. Quick MAC Address Flooding Question. If you do a show mac-address-table, you’ll see the CAM table — a table of MAC addresses that the switch knows; you would think that it would be empty since nothing’s plugge din, but the switch has its own MACs, so it always knows those guys. TCAM memory does not require the ASIC to execute loops through an algorithm to search the table. Memoria CAM y TCAM. g. Routing table is a Layer 3 table which states that for X. You cannot configure separate MAC table aging times for specific VLANs. From the command line, issue the appropriate command: CatOS devices: show cam dynamic. 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. For Cisco IOS software, issue the mac-address-table aging-time command. your assumption is correct, the arp entry is stale. Router prefix lookups happens in CAM. Advanced hardware is required to support IGMP snooping. Add a comment. The switching table entries are normally dynamically. and see all the mac addresses that the switch has seen frames travelling to and from. Hello Dyep, the aging time is the timer that decides how long a non speaking MAC address is stored in the CAM table before purging it. If you specify an address but do not specify an interf ace, the address is deleted from all. MAC Table C. A. My book says that when the MAC address table becomes fully, the switch goes into fail-open mode and broadcasts ALL frames to all ports except the ingress port. I just know that cam contain mac address, port and vlan information. CAM is most useful for building tables that search on exact matches such as MAC address tables. All Catalyst switch models use a Content Addressable Memory (CAM) table for Layer 2 switching. A “MAC table” tells you what data the table holds whereas a “CAM table” tells you in technical nature of the table – a content-addressable memory, or a cache, which. Routing table is a L3 table which states for X. prefer more space for routes or MAC addresses or ACLs). Thank you Daniel. A MAC flooding attack, also known as a MAC table overflow attack, is a type of network security attack that targets network switches. When looking up a prefix in a routing table, you don’t need an exact match, as long as the destination is contained within the prefix in the routing table, and that is where TCAM is used. The port of arrival and the VLAN are both recorded in the table, along with a timestamp. - 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). A switch learns about Ethernet MAC addresses at each of its ports so that it can forward packets only to the port that provides a link to the destination address of the. As frames arrive on switch ports, the source MAC addresses are learned and recorded in the CAM table. When performing a MAC address table lookup, the MAC address itself is the content being queried. The overall goal is to. bbbb. What is a CAM Table Overflow Attack? A CAM table overflow attack is a hostile act performed against a network switch in which a flood of bogus MAC addresses is sent to the switch. Start out at the network's center, or core, and display the CAM table entry for the MAC address. Figure 3-6 displays the typical CAM table population by a Cisco switch. In your local network, you use the forwarding table to get the other hosts mac addresses and send them the packets. Once the decision is made to route if through some network interface, the packet is delivered by. The default ARP table aging time is 4 hours while the CAM holds the entries for only 5 minutes. It is a search engine-based computer memory used for various search applications. So the only way to get the CAM table populated with all of the devices is to get all of the devices to talk. 03-02-2010 02:01 PM. Whenever a frame hits the interface of the switch it first checks the source MAC address and tries to find an entry for it in its CAM table if the entry doesn’t exist an entry is created, if it already exists then the aging timer for. ·. MAC addresses, and switch ports, along with their VLAN information. TCAM stands for Ternary Content Addressable Memory. Go to windows R --->> go to command prompt ---->> type ipconfig. The switch stores the CAM table in the RAM. It will flood it out all ports except the receiving port of the frame. The CAM table is the primary table used to make Layer 2 forwarding decisions. The ARP table is built from the replies to the ARP requests, recorded before a packet is sent on the network. Study with Quizlet and memorize flashcards containing terms like 1. . There seems to be a little confusion. A MAC address table, sometimes called a Content Addressable Memory (CAM) table, is used on Ethernet switches to determine where to. . 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. g. Cisco switches perform MAC address table lookups with CAM memory exact match. The CAM table assigns physical ports to MAC addresses. The switch enters these into the CAM table, and eventually the CAM table fills to capacity. In order to do this, "Macof" command is run in the terminal. MAC address table lookups happen in TCAM. 3. 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. I shut down the secondary link and then CAM table of the primary started filling up and packet loss. The switch adds the source MAC address to the MAC address table. level 2. 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. A point that seems to be misunderstood: some assume that the switch MAC table being empty corresponds with a quiescent state of the network and clients, e. Layer 2 switches have a MAC address table timeout or CAM aging timer which Cisco sets for 300 seconds by default. 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. On switch 1, the MAC address table would. Same as routers don't care about the destination address, because it is a group. CAM is Content Addressable Memory. C. TCAM also matches based on three values, 1=yes, 0=no, x="don't care. 12-18-2008 06:15 AM. C. Reply to A's IP address will get wrapped in the wrong. Your switch should have a MAC/CAM Table as a layer 2 device. 15 3 CAM vs. z. CAM table stores mac address, port and associated vlan parameters. "The CAM table is the primary table used to make Layer 2 forwarding decisions. No it won't work. The Catalyst 4500 and 6500 IOS Software are exceptions, however, and continue to use the mac-address. A switch can learn MAC addresses in two ways; statically or dynamically. a IP Address 1. The subnet on which Host A resides is a directly connected subnet. Click the card to flip 👆. 1 / 18. Copy. The layer-2 and layer-3 functions in a layer-3 switch are completely. If you have two networks, each with 100 devices on them, then the router has to learn, or remember, up to 200 MAC addresses. VIDEO 14 in the GNS3 Labs for CCNA 200-301. The Adjacency table records IP address and Layer 2 header for the IP and. Sorted by: 2. 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. ARP is very simple, so the table is updated with the latest broadcast, which is why arpspoofing tools send out broadcasts frequently. 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. The ARP timeout deals with the amount of time an ARP (layer-3 to layer-2 address resolution) entry remains in the ARP table before it is aged away. 4 Kudos. These usually expire every 5 minutes or so, and are updated by reading the source address of the frame entering the interface. - Router will strip out L2 overheads and based on its routing table will come to that 11. An ARP request's destination address is always the broadcast address. 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. It will configure the Cisco Fast and Easy Security feature. Content Addressable Memory (CAM) Table Overflow is a Layer 2 attack on a switch. An ARP table is composed of devices’ IP and MAC addresses. 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. z. Window pc don't have mac -address table . New addresses will then be learned. CLN member. Short for the Content Addressable Memory table, a table in memory of switches set aside to store the MAC address to a port translation table. 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. The CAM table is the primary table used to make Layer 2 forwarding decisions. With Cisco since CAM is used for other functions you can adjust what the priority is through SDM template configuration based on how the switch will be used (e. Hi, ARP gets the MAC address of a host or node and creates a local db that maps the MAC address to the hosts IP address. This causes the switch to act like a hub, flooding the network with traffic out all ports. As soon as a switch receives a frame, any frame, it extracts the source MAC from the header and enters it into it's CAM table. All CAM tables have a fixed size. When a packet come to the router, it use the FIB to select the route and it use the next-hop. Improve this answer. Suppose Computer A is connected to an Ethernet cable that plugs into the switch's Port 1, Computer B is connected to Port 2, and Computer C to Port 3. Mac address table overflow is a security vulnerability which attackers exploit by overflooding the CAM table to sniff the traffic. Within a very short time, the switch's MAC Address table is full with fake MAC address/port mappings. Adjacency table : The adjacency table is constructed at the same time as the RIB is populate using the ip of the next hop and ARP for L3 to L2 mapping to translate the ip to their corresponding layer 2 address. 4 - The switch adds B's MAC to the CAM table and forwards out of A's port that was previously registered an it lasts 300 seconds. B. And yes each interface needs a different MAC coz if more than one interface will have the same MAC the CAM table will be confusing. . 36d0 vlan 1 interface fastEthernet 0/1. It is a search engine-based computer memory used for various search applications. Storm Control allows you to set a threshold for Broadcast, Multicast, and Unicast Traffic entering a switchport that. By implementing router prefix lookup in TCAM, we are moving process of. It is used for Layer 2 frame forwarding and ARP tables. The CAM table used by a switch deals with the MAC address to interface resolution. Set timeouts for entries in the dynamic MAC Table and configure the static MAC table here. The switch views the Content Addressable Memory (CAM) table for the MAC address 00-bf-ac-10-00-01, and since there is no port registered with the NLB cluster MAC address 00-bf-ac-10-00-01, the. In a large network, discerning at which switch and switch port a MAC address can be found might be difficult. Information like MAC addresses, the routing table, or access lists are stored in these ASICs. This table is called a Content Addressable Memory (CAM) table. ” A. 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 helps data move efficiently on a LAN by sending data only to the. In the dynamic option, the switch automatically learns and adds MAC addresses to the CAM table. 2. An Ethernet switch in a switched network contains a CAM table that holds all of the MAC addresses of devices in the network. does L2 switches dont have this table. CAM table poisoning is one of them. Also to change a MAC manually the full commands are . MAC A. 12-18-2012 04:42 PM. Now let's break this down a little bit to understand how the MAC address table is built and used by an Ethernet switch to help traffic move along the path to its. Configuring the Aging Time for the MAC Table. The CAM table binds and stores MAC addresses and associated VLAN parameters that are connected to the physical switch ports. 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. Given a Cisco 3750, I can do a. mac-address-table was used until Catalyst IOS ver 12. You can lookup in the the table of any device within the same (V)LAN but the device that is the most likely to have the info is the router that act as the gateway for this (V)LAN. What is an ARP Tab. The switch only learns about MAC addresses when a device sends an Ethernet frame to it. 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. We will do simple ping from R1 to SW1 and see the MAC table on SW1 as below: R1#ping 9. D. MAC flooding is a technique of compromising the security of network switches that connect devices. En los Switchs, la memoria CAM (Content Addressable Memory) se utiliza para construir y buscar la tabla de. Router prefix lookups happen in CAM. The mac-address-table has nothing to do with IP addresses. The CAM can store MAC table and many other kinds of data - it is not limited to pure MAC addresses. 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. Yes the switch does know that ports 1 and 2 can not talk to ports 3 and 4 without something supplying routing. Switches connect multiple devices on a local area network (LAN). When MAC address-table entry for bbbb. 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 . 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 information. In this case, the CAM table results are used only to decide that the frame should. Cuidado: o comando mac-address-table synchronize apaga as entradas MAC roteadas. On most network devices, the command is either. Accordingly, a. 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. Only frames with a broadcast destination address are forwarded out all active switch ports. What does MAC flooding do? When an attacker tries to send a large number of invalid MAC addresses to the MAC table, this is known as MAC flooding. 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. H vlan 1 interface fastEthernet x/y. or does it get flooded to all connected ports due to the empty MAC Address table. MAC table = layer 2. This happens when a switch receives a frame with a destination mac address it does not have in the CAM table. Layer 2 network switches maintain a table in memory that matches MAC addresses to the switch's Ethernet ports. show ethernet-switching table The results show only interfaces for the Virtual Chassis master, although there are some ports connected on the VC slave. LAN switches determine how to handle incoming data frames by maintaining the MAC address table. Sorted by: 4. When queried, it will always return a binary answer; 0 for true or 1 for false. 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. MAC Address Table | CAM table Working | MAC Flooding | Defend against MAC Attacks #cybersecurity #cybercommunity #macspoofing #macflooding #macattack #CAM #c. This parameter must be increased to 14410 seconds so the L2 switch MAC address table timer purges the MAC address entry ten seconds after the directly attached routers purge their corresponding IP ARP entries. 123. به زبان خیلی ساده. how will be the lookup process in L3 switches. CAM Table. prefer more space for routes or MAC addresses or ACLs). Switch then acts as a hub by broadcasting packets to all machines on the network and attackers can sniff the traffic easily. Secure MAC addresses, either dynamic, static or sticky, are placed into the MAC address table. The mac-address-table static mac-address vlan vlan-id interface int disable-snooping command disables snooping on the. Op · 7 yr. The switch examines the destination MAC address of the frame. Attackers exploit the MAC flooding technique to make a switch and act as a hub, allowing them to easily sniff traffic. It is a specialized version of CAM depicted for quick table lookups. A router can operate as a switch. This is a safe assumption because. A switch learns unicast MAC addresses into its source address table or CAM table by inspecting each frame's source address. Switches uses an extension of a CAM, known as the TCAM or Ternary Content Addressable Memory. When a switch is in this state, no more new MAC. You can see this table with the. MAC address table, also known as Content Addressable Memory (CAM) table is a table that switches use to forward packets at layer 2. . Generally, the entries are for devices that are directly attached to the routing switch. Use the command to configure how long entries remain in the Ethernet switching table before expiring. O It will make the Ethernet interface on 0/1 faster. The MAC address table is contained in CAM, and ACL and QoS information is stored in TCAM. MAC address filtering involves configuring a MAC address switch to only accept packets from known MAC addresses. S1# show mac address-table. An ARP Request is used to find locate the MAC address and then map it to the port where the ARP reply is received. ·. Overall, the general answer is correct. The MAC address table is contained in CAM ACL and QoS information is stored in TCAM. 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. The interfaces that were added are for H1, R1 and the internal interface. A. 2. . 3b9. Information like MAC addresses, the routing table, or access lists are stored in these ASICs. 3. Example1: If a PC launches a packet, it will use the MAC address if the IP address is local (from the ARP table). Contributor In response to Elliot Dierksen. how will it help in L3 switching, 3. show (mac-address-table) Displays addresses in the MAC address table for a switched port or module. MAC address tables relate a MAC address to a switch interface, and that is completely different than what ARP does, which is to relate a layer-3 address to a layer-2 address. Switches will automatically populate the CAM table from framers that pass through the switch. . 0/8 NW is connected on xx i/f. All Catalyst switch models use a Content Addressable Memory (CAM) table for Layer 2 switching. In switches, CAM tables store the MAC addresses for different devices on its ports. A "CAM table" tells you what is the technical nature of this table - a content-addressable memory, or a cache, that performs parallel and fast lookups.