Which layer of network stack does access point operate?

Question

Which layer of network stack do access points operate? (My question also leads me to wonder https://superuser.com/questions/902820/which-device-can-create-a-new-network).

My question arises when reading Tanebaum's Computer Network:

1. So far in this book, we have looked at a variety of ways to get frames and packets from one computer to another. We have mentioned repeaters, hubs, bridges, switches, routers, and gateways. All of these devices are in common use, but they all differ in subtle and not-so-subtle ways. Since there are so many of them, it is probably worth taking a look at them together to see what the similarities and differences are.

   The key to understanding these devices is to realize that they operate in different layers, as illustrated in Fig. 4-45(a). The layer matters because different devices use different pieces of information to decide how to switch. In a typical scenario, the user generates some data to be sent to a remote machine. Those data are passed to the transport layer, which then adds a header (for example, a TCP header) and passes the resulting unit down to the network layer. The network layer adds its own header to form a network layer packet (e.g., an IP packet). In Fig. 4-45(b), we see the IP packet shaded in gray. Then the packet goes to the data link layer, which adds its own header and checksum (CRC) and gives the re- sulting frame to the physical layer for transmission, for example, over a LAN.

   

2. About access points:

   802.11 networks are made up of clients, such as laptops and mobile phones, and infrastructure called APs (access points) that is installed in buildings. Access points are sometimes called base stations. The access points connect to the wired network, and all communication between clients goes through an access point.

   

   Also from http://en.wikipedia.org/wiki/Wireless_access_point

   In computer networking, a wireless Access Point (AP) is a device that allows wireless devices to connect to a wired network using Wi-Fi, or related standards. The AP usually connects to a router (via a wired network) as a standalone device, but it can also be an integral component of the router itself.

   Another source says

   In a sense, it's very much like a hub in that it pays no attention to the data that crosses it - it simply sends everything that it receives on a wired connection to the wireless transmitter and everything that it receives wirelessly is sent to the wired connection.

Thanks.

Answer 1

Access points belong to the data-link layer (layer 2) devices.

An access point cannot create a new network. It only broadcasts whatever packet it receives...just like switches. A router is a good example of a device that can create a new network.