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34 votes
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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 ...
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23 votes
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What is real difference between host and node in network

I actually like the way the IPv6 RFC defines it: 2. Terminology node - a device that implements IPv6. router - a node that forwards IPv6 packets not explicitly ...
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20 votes
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How LAN works in video games if only one station is permitted to transmit?

Only one device is allowed to transmit at any given time. At any other given time, another device is allowed to transmit. How can you have a conversation at a dinner table if only person can speak at ...
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18 votes

How LAN works in video games if only one station is permitted to transmit?

Some LAN protocols, on some media, are half duplex. That means that only one host on a LAN can send a frame at any given time. The classic example of this is the original ethernet, but the modern ...
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17 votes

IP addresses from public IP block in my LAN

EDITED I'm assuming you're considering using an IP block that is not registered to you. Otherwise, skip to the last paragraph. Besides being a very poor practice, if you use public addresses on your ...
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15 votes

Why do we need MAC Address if we can uniquely identify each machine with an IP Address

There is a historical reason for this, as @ronmaupin alludes to. In small networks, you don't need a layer 3 protocol. All the devices are directly addressable, so layer 2 addresses work fine. As ...
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14 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 ...
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12 votes
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NEWBIE: How can two computers communicate if they are behind firewalls?

First: What you describe is NAT, not firewalling. A firewall just filters what can go through, a NAT device changes addresses in packets. You almost answer the first question yourself. Yes, a NAT ...
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12 votes

How is data sent from multiple different sources (computers) to the same destination host (computer) on a local network is handled by switch?

Switches forward all packets it receives to the best of its ability. If is unable to send a packet immediately, the packet is queued in a buffer and if the queue is full, the packet is dropped. ...
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11 votes
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Why we need IP address on LAN if switches can't read IP addresses

An IP address on a true layer 2 only switch is used for management (accessing the CLI remotely, sending SNMP traps, logging, TACACS/RADIUS, etc.). The IP address on the switch is in no way required ...
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9 votes
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MikroTik - problem with port bridge over LAN using 2 switches

I'd suggest to remove ports from bridge if it is possible to add them to switch group. When your ports are bridged - all packets going through these interface are processed using CPU while, if they ...
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9 votes

Can Ethernet frames only be transmitted in a LAN?

No, that's not correct. You don't need a router for two hosts to communicate using IP as long as they're in the same network.
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9 votes
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What precisely is a link?

There is no single precise definition for a "link". A link can be a physical layer connection, two ports connected by a cable. A link can also be understood as general connectivity by data link ...
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8 votes
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Why do LANs use MAC addressing instead of IP addressing?

You need to understand the network layers. They are independent of each other. Ethernet and IPv4 are currently the dominant protocols, but that was not always the case, and IPv4 is being replaced with ...
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8 votes
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Why do we need MAC Address if we can uniquely identify each machine with an IP Address

Don't confuse the network layers. Each layer has a specific purpose. Also, don't assume that there is only one protocol for each layer. Layer-2 has many protocols, some of which use MAC addresses, and ...
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8 votes

Speed benefits when switching from 1Gb copper LAN to Fiber Optic

You are conflating many things here, so let's try to detangle the issues in your question. Data rate is data rate, regardless of the physical medium. A 1Gb connection has the same data rate whether ...
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8 votes

Can Ethernet frames only be transmitted in a LAN?

NO. IP packets are encapsulated inside Ethernet frames. It's not one or the other.
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8 votes

How do two computers with different speeds communicate

I would imagine that with TCP A will resend the packages until it's gotten an acknowledgement for them all which would degrade A's performance because of having to resend packages all day long (...
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8 votes
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Why isn't 10.0.0.0/8 used instead of 192.168.0.0/16 for private addresses?

It is merely a necessity constraint and personal preference. If a Network is being built that would only have 10, or 20, or 50, or even 100 hosts, there is no reason not to use a /24 from 192.168.0....
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7 votes

Why do we use VLAN?

Besides the unknown unicast flooding that you allude to, broadcasts are necessary to the operation of ethernet. Some protocols require broadcasts. For instance, hosts use ARP requests (broadcasts) to ...
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7 votes

How do two computers with different speeds communicate

With directly connected computers, both need to use the same speed when sending to each other. Transmitting and receiving with different speeds requires splitting up the data into packets and some ...
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6 votes

Is Ethernet a protocol?

Well, it (obviously) depends on how you define a protocol. If we take Wikipedia's definition: In telecommunications, a communication protocol is a system of rules that allow two or more entities ...
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6 votes

Why do we use VLAN?

There can be many reasons to split a network into VLANs. Security seggregation. You may want to filter or forbid communication between some systems on your networks. Limiting of broadcast (and ...
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6 votes

How do two computers with different speeds communicate

In addition to the completely correct answers about speed matching directly connected systems ... One of the fundamentals of the internet (including all the private routing portions) is that the ...
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6 votes
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Error Detection across OSI layers confusion

I know that in the data link layer that is responsible ensuring that frames has been transmitted successfully by sending acknowledgement That is incorrect. There are very few data-link protocols ...
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6 votes
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How is data sent from multiple different sources (computers) to the same destination host (computer) on a local network is handled by switch?

A switch buffers frames - this is in contrast to a repeater hub that can't buffer anything. As @jcbermu has pointed out, both frames from A and B are first stored in their respective ports' receive ...
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6 votes
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What is the difference between DHCP and NAT?

Missing from the current answers is DHCP is a protocol for configuring hosts, and runs periodically to keep their addresses and other configuration up to date. The traffic is between the host and a ...
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5 votes
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What are the minimum requirements to be on the internet?

An internet (lower-case "i") is a network of networks. The Internet (upper-case "I") is what you mean. The Internet is the largest internet (network of networks). The networks comprising the ...
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5 votes

What devices are used to boost a UTP copper ethernet signal?

If the problem is on a long UTP copper cable pinned for ethernet, there are some solutions. Change the copper UTP cable to Single-Mode Fiber. It solves not only the distance problem, but it also ...
5 votes
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Is datacenter a lan?

The term LAN is rather amorphous. It can mean a single broadcast domain, a network on a single cable plant, a network in a building or small group of close buildings, etc. As far as the broadcast ...
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