Lets start with a brief but jam packed rundown of the OSI model, basically a Coles notes format. Lets start at the foundation and work our way up. Then I'll go into why I had to write this. I am not a fan m=of misinformation, even if it is innocent. I figure share the knowledge so others can SEE what is going on, and not just take others word for it. Like a mechanic firing the parts cannon at a car, sometimes he will get lucky. Buy a technician that uses his brain, and followed the logical order of things, will almost always come to a conclusion faster then someone shooting in the dark and hoping it sticks. Please don't take offense, just trying to shed light...
Layer 1: 'Physical' layer. This encompasses the physical structure of network elements, and include anything used to physically interconnect signaling paths. Be they optical, electromagnetic or wireless, Things like CAT5/6, Fiber, Copper, Wireless, and ethernet Hubs are all part of this fundamental layer. Hubs differ from switches, in that they are dumb. All traffic received on the uplink will be replicated to ALL ports. It doesn't care and doesn't track what is there. This can lead to collisions etc, which is why switches are preferred, however they exist at the next OSI layer. Like the old saying goes " Silly user, Hubs are for workgroups"
Layer 1 also dictates how the physical topology is setup. Star, Ring, Wifi, Mesh, etc.. as well as link speed and duplex based on physically available connectivity devices (ie: 10/100/1000 copper port, or 10G SFP fiber) Bit rates and synchronization are also handled here. The fundamental function of the OSI layer 1, is the Modulation and demodulation of signaling from digital 1's and 0's, to analog or 'physical' medium in On / Off patterns. So, Without Layer 1, NOTHING works. Like having a cake with no flour....
OSI layer 2: the 'Data Link' Layer; This encompasses the LLC (Logical Link Control) , error controls, data frames such as Ethernet, PPP, that encapsulate the 0's and 1's into a more manageable format then a string of on and off. Bridging (via MAC bridge tables) is handled by Layer 2 packet switching. A note on Switches; Switches are involved in the data link layer ( Layer 2) handling traffic based on the physical MAC address, irrespective of protocol being used. The Media Access Control addressing is the actual physical address of the device on the network, and it functions at this second layer. In contrast to a Hub, as previously mentioned, a Layer 2 switch does NOT spam everything to every port. It instead maintained a table of what MAC's are coming from what ports on the switch. Those would be the MAC bridge table.
Protip: I keep a 100meg dumb hub in my bag, in the event I am working on a switch that does not offer port mirroring, or is just a simple unmanaged L2 switch, a hub can be used to sniff and capture traffic on the wire to see what's going on and do protocol analysis, so long as the host you are trying to troubleshoot is connected somewhere downstream to that hub. This only works because of the aforementioned differences in a switch and a hub and how they address the packets. Hubs don't care, so it's inherent insecurity is one of the major reason we do not use them anymore.)
Layer 3 in the OSI model is the 'Network layer', and it's prevue is the transmission and organization of data packets between networks. Your routers routing functions work here, at layer 3. Services provided by the device are software based application etc, that are all present further up the OSI model.
This layer handles the encapsulation of data packets, fragmentation of those packets into a manageable and transmittable format. It takes care of logical addressing to differentiate between source and destination networks, Outgoing data is fragmented into packets at this layer, and subsequently reassembled at this layer on the far end, and passed further up the OSI model to applications who can make use of the format provided by the layer 3 functions. Your IP protocol stack sits here, so this is where your "ipconfig / release /renew " is happening, as well as your "netsh int ip reset"
The next layer is Layer4, the 'Transport' layer; Now that we have physical 1's and 0' converted into manageable hex data, and that data has been encapsulated in a packet, given source and destination addresses, source being bound to the devices MAC so we can get return packets back to their originating host, the data fragmented and ready to be transmitted over whatever medium is being used at L1, we need to transport it. So here we provide mechanisms such as error control, flow control, and congestion control to keep track of the data packets, check for errors and duplication, and resend the information that fails delivery. Packet Segmentation and reassembly ensure that the data is divided and sequentially sent to the destination where it is rechecked for integrity and accuracy based on the receiving sequence.
Service-point addressing functions to ensure that the packet is sent in response to a specific process (via a port address). The TCP in TCP/IP V4 and TCP/IPV6 functions here. TCP is Transmission Control Protocol. UDP also functions here (User datagram protocol). TCP has more overhead due to the constant confirmation that the packets are received at the far end. UDP just sends the data and deosn't care if it gets there. TCP is Transactional in nature, and this is how it's error correction and delivery confirmation works.
The next layer, Layer 5 is the 'Session' layer. This is where software starts to play a role in managing sessions between clients and servers. Authentication, establishing and tearing down sessions, setting up media session, including replaying specific IP and port numbers for media would be specified here in the Session layer with something like an SDP ( Session Description Protocol), or SCP and Point to point tunneling. API's Sockets and yes, WinSock (netsh int Winsock reset happens here)
Layer 6 is the 'Presentation' or 'Syntax' layer and is where things like SSL, SSH, IMAP, FTP, MPEG, JEPG etc happen. So Encryption, Decryption, Data conversion, character coding, data compression. Layer 6 maps the semantics and syntax of the data so the received information is consumable for each distinct network operation. IE: we transfer data from our encryption-based communication app, so it is formatted and encrypted at this layer before it is sent across the network.
On the other end, the data is decrypted and formatted into text or media information as originally intended. The presentation layer also serializes complex information into transportable formats. The data streams are then de-serialized and reassembled into original object format at the destination.
And, Lastly, we have the 'Application' layer at Layer 7. This is the User level layer, and interfaces software elements with the data. Things like HTTP, FTP, IRC, SSH, DNS are all applications ( tho the encryption portions of ssh happens at L6) So, your Flush DNS, happens here.
So, NOW. All that said, answer me the following: How would you expect to connect to a mobile hotspot exactly with no WiFi adapter showing present( Layer 1 is missing)? And as noted above, the flush dns, Winsock reset, ipconfig / release / renew are all happening AFTER the physical, Layer 1.
To me this seems like a buggy software / driver issue. It is happening to way to many for it to be a coincidence. Mine shows the BT adapter still available, but the wifi not even present. They are physically housed on the same chip, using the same radios.(L1) It's either that or the Bluetooth stack(L2) doesn't care if the hardware is present and will just flake out if I try to connect it. I suppose using a USB ethernet adapter would work to get online and download drivers, but being as their is the second time that this user had had their Wifi card 'disappear', Maybe a USBc Wifi Dongle is the best option?
I've seen lots of posts also stating to do netsh int ip reset, a Winsock reset followed by a flush dns, release and renew. The problem with that, is those are further up the OSI stack, and therefore CAN'T work if the hardware isn't there, or isn't being identified by the OS. Layer 1 is hardware folks. Learning the OSI layer stack is fundamental in understanding how any network functions.
