Can anyone explain in detail how an ARP packet is sent over wireless ? Because when I captured ARP packets with Wireshark, I could see Ethernet-II header in it. Ethernet uses 802.3 (with CSMA/CD) whereas Wireless communication uses 802.11 (with CSMA/CA).

I am not 100% sure this is the full answer, but I can tell you that TCP/IP networking and the OSI networking model are layered, in the case of OSI it is 7 layers, in the case of TCP/IP networking it is 4-5 layers depending on the source of the information. References: http://technet.microsoft.com/en-us/l.../cc958821.aspx | http://www.vlsm-calc.net/models.php

The layers are:

Physical | Internet | Transport | Application

The above reference show the mapping between OSI and TCP/IP.... but I digress

The Physical layer consists of the wires and the actual connections (ports and electrons over the wire or radio signals over wireless) These are your 802.3 and 802.1 protocols. MAC address while technically a feature on the physical layer is not tied to the physical protocol, and ARP which uses the MAC address within a broadcast segment is really a feature of the Internet layer. Therefore an ARP broadcast is independent from the physical 802.3 or 802.11 protocol. Why do you see the Ethernet-II header? Because you are capturing Ethernet packets, which means the ARP requests are being transmitted by Ethernet packets which are a function on the Physical layer within the TCP/IP model. If you were capturing packets over the wireless you might see a different header in the packet.

I hope this helps answer the question

Thanks.
But sorry, I forgot to mention that I had captured these packets on wireless interface.
I have removed the LAN cable as well to avoid any ambiguities.

And still I am getting Ethernet-II header.

If you read this it would seem that WiFi still uses the Ethernet frame structure. http://www.wireless-center.net/Wirel...ions/1923.html

Both Protocols are in the 802 protocol family so they share quite a bit, I am not a standards expert but the sub version of the standard very likely only applies to certain aspects of the transmission in this case collision avoidance in 802.11 vs collision detection in 802.3 Both using the same standard frames to transmit data, but the protocol for how the data is transmitted may be different. If you reference the links I have provided the reading I did in them would seem to bear this theory out. http://standards.ieee.org/about/get/802/802.html http://en.wikipedia.org/wiki/IEEE_802

To be completely truthful unless you, I or someone else actually reads through the entire 802 base standard and then the subversions .3 and .11 you are unlikely to get a definitive answer, unless someone fully versed in them happens upon the thread.

My final say on a possible explanation is ... In my education many years ago, and from this little refresher as I went down the rabbit hole from the Wikipedia page it would seem to me the two subversions are only definitions of the transfer method not that frame structure. If you also look at the list of the subversions of the 802 standard that would logically make sense as they are all different type of physical transport methods like Fiber, Token Bus, Blue Tooth, etc...

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Thanks,
I will go through the links.

May be just because the 802.11 header does not provide the upper layer protocol type field, ARP uses Ethernet for passage over medium. At sender side i must be encapsulated inside the 802.11 frame and then transferred over wireless medium. At receiver it must be decapsulated.

Hopefully I am correct.

Take a look at this http://www.studioreti.it/slide/802-11-Frame_E_C.pdf specifically slide 2, it looks like 802.11 is encapsulating the 802.3 or using those frames somehow. This might help too http://www.mhprofessional.com/downlo...524_chap02.pdf

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How exactly this is done is still not clear.
But it seems to be the closest answer to the question.
Thanks for the help.

I believe I have found our definitive answer. The payload of a packet in both the 802.11 and 802.3 standards (pretty much the whole 802 standard) are defined by the ether type. So the header of an ARP request would be the same as in both. Take a look at this http://en.wikipedia.org/wiki/EtherType and then specifically the following is the explanation
"With the advent of the IEEE 802 suite of standards, a SNAP header combined with an IEEE 802.2 LLC header is used to transmit the EtherType of a payload for IEEE 802 networks other than Ethernet, as well as for non-IEEE networks that use the IEEE 802.2 LLC header, such as FDDI. However, for Ethernet, the Ethernet II header is still used."