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Why is the CAM table in a switch called CAM table and not MAC table even though it holds MAC addresses?

CAM (Content Addressable Memory) is memory that can be addressed by content, rather than a numeric memory address. You can look up the interface by presenting the memory with the MAC address. This is ...
Ron Maupin's user avatar
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19 votes
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Why can't devices in different subnets talk with each other?

Devices in different subnets can communicate. That is the purpose of a router. Routers route packets between different networks. Even if devices in different networks are on the same layer-2 ...
Ron Maupin's user avatar
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18 votes
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Can a switch that does NOT support VLAN capability be considered a managed switch if it has other features?

Yes. A managed switch is a switch you can configure in some way or other. Whether it supports VLANs or not is not the question. Even a switch (or a hub for that matter) that only provides status ...
Zac67's user avatar
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15 votes

Why is the CAM table in a switch called CAM table and not MAC table even though it holds MAC addresses?

CAM - Content Addressable Memory, referring to the memory used for the MAC address table. It works kind of reverse from RAM, you address it by giving it content and it returns you the address where ...
manish ma's user avatar
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14 votes
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RIB vs FIB differences?

The forwarding information base (FIB) is the actual information that a routing/switching device uses to choose the interface that a given packet will use for egress. For example, the FIB might be ...
rnxrx's user avatar
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14 votes
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Does a switch understand packets? If yes, what is the frame terminology for?

You need to understand the concept of layers. An application will send data to the Transport Layer. The Transport Layer protocol will encapsulate the data inside headers for the Transport Layer ...
Ron Maupin's user avatar
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14 votes
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Is there a performance difference between a managed an unmanaged network switch?

Good question. The short answer: No, there's no inherent difference in the speed or latency available to hosts talking to one another on a managed vs. unmanaged switch. In reality though, you'll ...
Ted Quanstrom's user avatar
14 votes
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Difference between Giant Frame and Jumbo Frame

Generally, a giant frame is a frame that is too large for the receiving interface. As a malformed frame it is dropped. A jumbo frame is a frame that is larger than the standard allows (1518 bytes for ...
Zac67's user avatar
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13 votes
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Is there any reason to use a hub over a switch?

For the most part, no. Hubs are also known as repeaters - meaning that they basically echo whatever is coming in to a given port out all other ports in the domain. The idea is (or, more properly, ...
rnxrx's user avatar
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12 votes
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Should I disable STP on my access ports?

You really, really do not want to disable STP where you connect switches to other switches. That is the entire purpose of STP. If you disable STP, and there is a problem, it will really be too late ...
Ron Maupin's user avatar
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12 votes
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Does a switch always get a MAC address from a PC?

A switch learns the source MAC from the sender. If the destination is not in the CAM table, the switch floods the frame out all ports. So if the receiver never responds, the switch will never learn ...
Ron Trunk's user avatar
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12 votes
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Does an unmanaged switch deal with IP addresses at all

An unmanaged switch doesn't use/care for/understand IP addresses at all. A managed L2 switch uses IP addresses for management only. Some L2 switches also support limited L3/IP functionality like ACLs. ...
Zac67's user avatar
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11 votes
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Difference between routing, forwarding, and switching

In general, forwarding refers to a device sending a datagram to the next device in the path to the destination, switching refers to moving a datagram from one interface to another within a device, and ...
Ron Maupin's user avatar
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10 votes
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What's use of Port Isolation vs traditional VLANs?

Port isolation -also called private VLAN (thanks @Stuggi)- is a very useful feature for switches that connect end users. In a typical network you will have many end-users computers grouped together ...
JFL's user avatar
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10 votes
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MAC Address learning process

It depends on the manufacturer. For Cisco switches: Switch port configured as access and frames received tagged on different VLAN Frame is dropped Switch port configured as trunk and frames ...
Ron Trunk's user avatar
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9 votes

Why non-blocking switch needed?

However, as the term suggests, "theoretical" maximum speed is just a theory and it rarely happens in real-life conditions. That depends on your life, I guess. In my day job, we try to ...
Jörg W Mittag's user avatar
8 votes
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How IP helper address works?

Using the ip helper-address command sets up a DHCP relay. DHCP only works on the LAN to which it is connected because it uses broadcast, which cannot cross a router. To remedy that situation, DHCP ...
Ron Maupin's user avatar
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8 votes
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Router benefits in 2018 compared to a L3 Switch

It usually comes down to options and resources, where routers have more of each. Routers often have the ability to have different types of interfaces that are not available on switches. They also ...
Ron Maupin's user avatar
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8 votes

Posible to connect VLAN switch through dumb switch?

An unmanaged switch will only have one VLAN. Some unmanaged switches will drop tagged frames as damaged, others will strip the tag, and some will simply pass the frames unchanged. Unless you try it, ...
Ron Maupin's user avatar
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8 votes
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Why would a switch ever send an ARP request for a MAC address when it can just wait for the first packet to be received from a device?

You are confusing switching, where a switch creates and updates a MAC address table as frames pass through it, with the switch management. Switching is a layer-2 function, and a dumb switch will ...
Ron Maupin's user avatar
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8 votes
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Two switches, double connection, no LACP: how does it work?

Most likely, the rapid or the multiple spanning tree protocol RSTP/MSTP has been activated on the 1910 switch. With the unmanaged 1410 switch forwarding STP BPDUs (most do), the 1910 notices a loop to ...
Zac67's user avatar
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7 votes
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Is there a way to detect how many switches are between a host and the router?

No, there isn't. Switches are transparent devices. The frames which the host sends will be the same frames as the host (a router is just a host to a switch) on the other end of the switches receives. ...
Ron Maupin's user avatar
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7 votes

Can a switch that does NOT support VLAN capability be considered a managed switch if it has other features?

Yes, "manageable" obviously refers to the fact that you can manage the switch, rather than to one specific feature such as VLAN. Among other things, some useful features such a switch could have: ...
JFL's user avatar
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7 votes
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Does it make sense to map a VLAN to each LAN?

Using VLANs is like breaking a switch into multiple unconnected switches. On a single switch, no hosts on a VLAN will ever see any traffic for a different VLAN. Traffic must pass through a router, ...
Ron Maupin's user avatar
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7 votes

LACPDU packets to pass through unmanaged switch

As Ron Trunk pointed out, LACP uses a special multicast OUI on its frames. Your unmanaged switch does not recognize the OUI, only that it is multicast, and it sends the multicast frames to every other ...
Ron Maupin's user avatar
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7 votes

Can a single subnet work across several switches?

Without VLANs, connected switches form a single broadcast domain - that is exactly what you need for a single IP subnet. Just connect away. VLANs require managed switches and allow you to split (...
Zac67's user avatar
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7 votes
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Can a single subnet work across several switches?

Yes. You don’t even need a trunk. If all ports on both switches are access ports on Vlan 3, then the port connecting the two switches are on Vlan 3 and both switches form one broadcast domain on that ...
Darrell Root's user avatar
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