Why do we need Address Resolution Protocol? [closed] - networking

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I understand the mechanism of ARP but I am wondering why do we use it even if we have the recipient's IP address? Isn't it enough to rely on the recipient's IP address to send packets instead of taking extra steps of finding its matching MAC address?
Thank you.

An IP address is a layer-3 address. Layer-3 packets get encapsulated into layer-2 frames, and layer-2 also has addressing (MAC addresses) which needs to be supplied. ARP (Address Resolution Protocol) resolves the layer-3 IP address to a layer-2 MAC address so that the layer-3 packet can be encapsulated into a layer-2 frame which is then sent out the layer-1 interface.

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Are TCP/IP and UDP the only protocols supported by the Internet? [closed]

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Closed 2 years ago.
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Are TCP and UDP the only protocols supported by the Internet? If they are, do other networking protocols that are not meant to be used with common hardware exist?
No, not at all. The Internet is routed at the network layer, which is IP.
The problem is that NAPT that is used for IPv4 because we have run out of those addresses only supports TCP, UDP, and ICMP. IPv6 restores the IP end-to-end paradigm and you can use any transport protocol because the Internet only cares about IP, not any protocols above that.

Address Resolution Protocol (ARP) & RARP in netwrokig [closed]

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ARP and RARP are the main Protocol uses in Link Layer. To do the ARP request, a device requires IP and MAC address pair for broadcasting. So my question is ARP doing the mapping the IP to MAC by referring the data
and operates using the LAN.
So RARP is the reverse algorithm of that like mapping logical address to physical address in caches in Computer Systems.
I hope a good answer from the community.
There are dozens of protocols that use the data-link layer the same way ARP does, including IPv4, IPv6, etc. See IEEE 802 Numbers for a list of protocols that use the data-link layer.
For protocols in the data-link layer, there are/were many. For example, token ring, ARCNET, FDDI, frame relay, HDLC, ATM, PPP, etc. Ethernet used to be the king, but Wi-Fi has dethroned it since there are more devices shipping with Wi-Fi interfaces than devices with ethernet interfaces.

Addressing among private ip-addresses in networking [closed]

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So, i was reading networking in depth. One concept i failed to understand was how different machines in LAN manage to access internet through one public IP address provided to company by ISP.
For eg. let's say the public address provided is 244.13.5.89. And all the machines when get to internet, they all are recognized as 244.13.5.89 despite their private address being 192.168.3.x, which is fine. But now when the router sends the request for each of these machines, how does it maps each response to respective machine?
If the answer is NAT, what entries does NAT has? Is there port no. or something else?
I will give you the idea about the complex case scenario :-
If all datagrams arriving at the NAT router from the WAN have the same
desti- nation IP address (specifically, that of the WAN-side interface
of the NAT router), then how does the router know the internal host to
which it should forward a given datagram?
The trick is to use a NAT translation table at the NAT router, and to
include port numbers as well as IP addresses in the table entries.
See more details about NAT Table here.
SORRY, don't know why it took me minutes to post an answer, it was not allowing me to add the answer...
NAT has following fields:
source computer address and website, so when it receives packet it will replace source computer address with its public address, and send it to the internet once response comes back it sees oh this come from the website and it was requested by the source computer. It will again replace destination address with source computer address and send it in LAN.

Difference between IP address and MAC address? [closed]

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I know they are address schemes used in different layers, and that IPV4 is 32 bits while MAC is 48 bits.
My questions are:
Why do we need two different address schemes?
What is the problem if we decided to use the same address for both purposes?
Is there a reason for the MAC address requiring more memory?
Has the introduction of ipv6 changed anything?
MAC addresses is a Layer 2 Address, while IP is a Layer 3 Address.
Layer 1 is phisical layer
Layer 2 is data link layer ---> MAC ADDRESS
Layer 3 is Network Layer ---> IP Address
http://en.wikipedia.org/wiki/OSI_model

How many address does a computer have to identify? [closed]

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It's well known there is the IP address (ipv4 or ipv6) and the MAC address, but does it exist another addresses?
IP address and MAC are related to Network Interfaces (Wifi interface, Ethernet ,PPP..), and PC could have many interfaces .

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