8

Caveat: This question might raise primarily opinion-based answers, and might be put on hold or considered off-topic, for exactly that reason. Still, I dare to attempt an answer: Following https://en.wikipedia.org/wiki/Ad_hoc#Networking The term “ad hoc networking” typically refers to a system of network elements that combine to form a network ...


8

First, Wi-Fi (IEEE 802.11) is not ethernet (IEEE 802.3) any more than token ring (IEEE 802.5) or any of the other IEEE LAN standards other than 802.3 are ethernet. The frame headers are different for Wi-Fi and ethernet. Wi-Fi, ethernet, token ring, FDDI, etc. are all LAN standards for OSI layer-1 and layer2 which encapsulate datagrams for upper layer ...


7

Based on your questions and comments, I think you are missing the point of the two articles you are referencing. When they are talking about "Raw Ethernet," they are talking about data frames that do not contain any IP (L3) or TCP/UDP (L4) headers. They are not talking about using L2 frames without L2 headers. Without the L2 headers, a frame would be ...


6

Mike's suggestion to read RFC 3561 - Ad hoc On-Demand Distance Vector (AODV) Routing should do the trick; in the meantime, I will go ahead and summarize it for you. Wireless (routing) protocols, such as AODV protocols, use sequence numbers in a different way than wireline protocols do. AODV maintains a table of destination IP addresses, along with the last ...


5

Just so we're clear on terminology, in the 802.11 spec, Ad-Hoc is a mode of operation of the wireless client interface - this allows direct connectivity between two (or more) wireless stations that have the same SSID configured. This is as opposed to Infrastructure mode in which the wireless interface or station must be able to associate to an Access Point ...


4

No, we can't. What we can do, with better modulation, is approach the shannon limit more closely. Otherwise, if you need more bandwidth (in megabits), either increase the bandwidth (in (mega)Hertz), or increase the signal/lower the nose to get better SNR.


4

Do wireless devices such as smartphones transmit beacon equivalent frames such as APs do? A wireless client does not transmit beacon frames. However if a device is configured to provide service (i.e. tethering, etc), then it is acting as an access point and would transmit beacons. Can they be made to announce their presence somehow using layer 2 frames ...


3

As the already present answer point out, ad hoc is a matter of perspective. From a user's POV an ad-hoc network should be effortless and require no planning. If this precludes bringing along a cable, then yes, it needs to be wireless. If you admit a cable you can connect two machines with Ethernet. Using obsolete 10BASE2 coax cabling you could even connect ...


3

Wireless Sensor Network (WSN) and Ad hoc Network differ in one important factor: Infrastructure-based vs Infrastructure-less. In WSN, network is managed by a base station such as these antenna around us that receive our data and phone calls. The previous is based on definitions that may be a bit lacking. Simply stated, a WSN is neither infrastructure based ...


3

At least in the context of network devices clock synchronization tends to refer to synchronous circuits where a constant time signal has to be maintained so that two devices can know the precise rate at which data is being transmitted and received. If the respective clocks of two devices are skewed then the integrity of the circuit will suffer. As such it'...


3

This is one of those "it depends" questions. It depends on How much of a risk rogue APs are to the organization. How well you can detect unknown devices being connected to the network. Only you can answer this question for your organization.


3

Routing convergence means that all the routers have received all routing updates and have updated their routing tables to reflect the changes. Different routing protocols propagate routing changes in different ways, with different timing. For example, some routing protocols send all the routes to neighbors periodically, so changes can take a long time to ...


3

Routing is considered a layer-3 function, using layer-3 (IPv4, IPv6, IPX, AppleTalk, etc.) addresses. Routing involves a path selection based on the layer-3 destination address. A router uses a routing table to determine the path used to forward the layer-3 packets, and it drops any packets for which it has no path. Bridging/switching is considered a layer-...


3

802.11 specifies clients listen for AP beacons. They don't broadcast anything. However, real world implementations (Windows, iOS, etc.) actively hunt for known SSIDs when they aren't associated. These probes will broadcast a MAC, but in the case of recent-ish iOS, Apple randomizes the MAC for these probes. (to thwart attempts at passive tracking)


3

Case of RREP: When nodes receive RREQ (Route request) for a destination node, then two types of nodes can respond to it. One is the destination node itself -- in this case, it can increase the seqeunce ID. The second types of nodes are those that have an existing route to the destination node. Now, they have already saved the seq number that was generated by ...


2

These two sequence numbers help avoid looping and stale routes in the route discovery process. They act as a time-reference (using it for a lack of b identifier for the originator of RREQ and the intended receiver (destination) of the RREQ. Since they act as a time-reference for different nodes, there is no duplication! The RREQ ID (let us seqA) identifies ...


2

I think SSID isolation is not the same as Client Isolation. Some controllers will have both and I believe they perform two different tasks. With SSID isolation, it simply means that if you have multiple SSID's and clients connected to them, the clients from different SSID's will not be able to communicate. With client isolation ( which is what you want ), ...


2

1.) The Microchip wifi Beacon announces the network, I assume the BSSID is randomly assigned in IBSS / Ad Hoc mode. To some degree, this is true. For clarity, from IEEE-802.11-2012 section 10.1.4.1: When a STA starts a BSS, that STA shall determine the BSSID of the BSS. If the BSSType indicates an infrastructure BSS, then the STA shall start an ...


2

According to my understanding, they are two different entities. They are completely independent of each other. A node's sequence number gets incremented either when it broadcasts a RREQ packet or when it is the destination node, before sending the RREP packet.


2

There are a couple of issues here. 1) I'm not sure of all IP network stacks, but often the driver will drop packets it perceived to be sent by itself. This can often be got round with listening for raw packets, but this will require a privileged state 2) What address does this get sent back to. Generally applications (and possibly the IP stack), expects to ...


1

Yes your assumption is correct when traditional routing is used(proactive routing). If you used traditional routing, it create routing table before packet is sent. Maintenance of routing tables requires much bandwidth Dynamic topology much of the routing information is never used Waste of capacity Flat topology- No aggregation But when you used reactive ...


1

About the term The term "Ad Hoc" seems to have completely different meanings in different contexts. In wireless LAN context "Ad Hoc" means that all devices in the network have the same role. The opposite is an "Infrastructure network" where one device has a special role. The data format (OSI layer 2) is slightly different in both types of networks. (Note ...


1

(Edited) Sorry. I meant the following: If you set the RTS value to 0 then the behavior is implementation based. Some vendors might have a "disable RTS" concept, and other might have "always enable RTS" concept. If you want to surely disable RTS, then set a very high value like 2500 or 3000. But I would recommend you do the following to set the right RTS ...


1

Routing protocols, including AODV, do not assign IP addresses. That is handled by other means (DHCP for example). Two hosts with the same IP address is an error condition, so that should not happen under normal circumstances.


1

If your home wap has vlan capability you can create two SSID's. Assign each SSID to a vlan. Then, assign ACLS (access control lists) to allow them to get to the Internet but block them from your addresses. Some home WAPs also have guest mode and features that don't let computers talk to other computers on the same network. To add... you can get a robust ...


1

The wikipedia description is wrong. In an ad-hoc network, nodes communicate directly. What they are describing is a wireless mesh network (aka: 802.11s). Also, your understanding of ad-hoc is flawed. "A" doesn't "create the network". In an ad-hoc network, there are no controllers. Nodes communicate with each other directly, and independently. "A" may have ...


1

I would like to do a similar test but in a wireless environment. Look at Wifibroadcast (Linux, some Android support) which does exactly that. Short summary: it uses a pair of wifi adapters, one in injection mode, the other in monitor mode, and transmits data using raw wifi frames. This is an unidirectional connection. While originally conceived as a method ...


1

From The Dynamic Source Routing Protocol for Mobile Ad Hoc Networks: As a node overhears routes being used by others, either by promiscuously snooping on them or when forwarding packets, the node MAY insert those routes into its Route Cache, leveraging the Route Discovery operations of the other nodes.


1

It's impossible to answer your question because there are some assumptions wrong in it. First, in OLSR not all nodes generate TC messages. Only nodes that have been selected as a MPR generate and relay TCs. Second, the node generating the TC message includes in it the list of all its symmetric neighbors, not just those that have selected it as a MPR (i.e. ...


1

A TC (Topology Control) message sent by a node x contains a list of all symmetric neighbors of the node x, not just the nodes that have selected x as a MPR. So your question contains a wrong assumption. Including only MPRs or MSs in a TC message wouldn't allow all nodes in the network to get full topology information about the whole network.


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