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<a href="http://www.geocities.com/SiliconValley/Vista/8672/network/arp.html#A2" rel="ugc">http://www.geocities.com/SiliconValley/Vista/8672/network/arp.html#A2</a><br />
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The confusion may come from: <a href="http://en.wikipedia.org/wiki/Address_Resolution_Protocol" rel="ugc">http://en.wikipedia.org/wiki/Address_Resolution_Protocol</a><br />
&quot;ARP can be used to resolve MAC addresses to many different Layer 3 protocols addresses. ARP has also been adapted to resolve other kinds of Layer 2 addresses; for example, ATMARP is used to resolve ATM NSAP addresses in the Classical IP over ATM protocol.&quot;<br />
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So definitly ARP works over Layer 2, but it used to resolve Layer 3 or other Layer 2 addresses.<br />

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http://www.geocities.com/SiliconValley/Vista/8672/network/arp.html#A2 [http://www.geocities.com/SiliconValley/Vista/8672/network/arp.html#A2]

The confusion may come from: http://en.wikipedia.org/wiki/Address_Resolution_Protocol [http://en.wikipedia.org/wiki/Address_Resolution_Protocol]
"ARP can be used to resolve MAC addresses to many different Layer 3 protocols addresses. ARP has also been adapted to resolve other kinds of Layer 2 addresses; for example, ATMARP is used to resolve ATM NSAP addresses in the Classical IP over ATM protocol."

So definitly ARP works over Layer 2, but it used to resolve Layer 3 or other Layer 2 addresses.


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Here;s the best short explanation I have seen.<br />
ARP returns the layer 2 address for a layer 3 address.<br />
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<a href="http://www.answers.com/topic/address-resolution-protocol" rel="ugc">http://www.answers.com/topic/address-resolution-protocol</a><br />

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Here;s the best short explanation I have seen.
ARP returns the layer 2 address for a layer 3 address.

http://www.answers.com/topic/address-resolution-protocol [http://www.answers.com/topic/address-resolution-protocol]


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In some books i read that ARP protocol is at Layer 2 of TCP/IP stack but in some other it is mentioned there that the ARP is at Layer 3 of TCP/IP stack , where it is actually? i am confused about it.<br />
Can you explain with authenticated references please
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In some books i read that ARP protocol is at Layer 2 of TCP/IP stack but in some other it is mentioned there that the ARP is at Layer 3 of TCP/IP stack , where it is actually? i am confused about it.
Can you explain with authenticated references please

ARP is at Layer 2 or Layer 3?

Networking software modules are interfaced with a framework implemented on the machine's operating system that implements the networking functionality of the operating system. The best known frameworks are the TCP/IP model and the OSI model. Systems typically do not use a single protocol to handle a transmission. Instead they use a set of cooperating protocols, sometimes called a protocol family or protocol suite.[9] Some of the best known protocol suites include: IPX/SPX, X.25, AX.25, AppleTalk and TCP/IP. Other protocols indirectly related to networking include the hypertext transfer protocol (HTTP) and its related technologies, Dynamic Host Configuration Protocol (DHCP), Domain Name Server (DNS) and other Internet protocols.