we are currently considering whether ns3 satisfying our requirements, we're looking for a convenient tool to run in distributed devices in the real network (every kind of possible connections) and capture the network performance data (like a sniffer). I realize that the primary purpose of ns3 is to simulate network topology in a single machine, but its emu module sounds promising and the flow monitor can save our effort on data capture.
In the following link
http://www.nsnam.org/wiki/HOWTO_make_ns-3_interact_with_the_real_world
it is declared that NS-3 EMU can be applied to inject simulated nodes interacting with real live network, and 3 kinds of testbed are given. However the first solution, virtual machine vmware testbed is still woking within LAN -- in promiscuous mode the virtual machines network card are listening to all LAN broadcasts so that the emu-udp-echo server and client can find each other.
My question is, is it possible that the emu-udp-echo server/client running in different, physical systems from different positions in wide network?
e.g. in different cities or from different network providers, given ip address of the hardware where the other ns-3 node is running? if it is possible, how can i specify the "real" ip address and port for the node, instead of assign a virtual ipv4 address?
Thanks a lot.
Yes, while the documentation describes how to perform this using virtual machines, this can be done in general on real hardware. Since that HOWTO was written, there has been additional work on providing helpers for running this type of experiment, including running on PlanetLab testbed machines. This documentation describes the generalized file descriptor NetDevice, added to the ns-3.17 release: http://www.nsnam.org/docs/release/3.19/models/html/fd-net-device.html. A similar example to the one described in that HOWTO is found in the file fd-emu-udp-echo.cc.
When using emulation mode on real networks, configuration of the MAC addresses and IP addresses must be done carefully. First, the device must be able to be put into promiscuous mode. Second, the MAC address needs to be different than the hardware address of the NIC. If you intend to be riding on top of an active NIC with existing IP address (in use for other Internet traffic), you'll need to have another IP address for ns-3 that is within the right link subnet. If instead you want to dedicate the NIC to ns-3 use, then do not assign the IP address to the host NIC and just assign it to the ns-3 configuration.
The PlanetLab example also shows another configuration that uses Tap devices to send data to/from PlanetLab testbed nodes. Some of this configuration is specific to how PlanetLab works, but the use of Tap device bridged to an ns-3 device may also facilitate emulation.
Related
is it increasing your internet security in terms of privacy/tracking/fingerprinting, if you are surfing with your web browser in a virtual machine enviroinment (virtual box + vpn)? Instead of surfing from your normal windows operating system...
Or is a virtual machine not helping you in fingerprinting cases? I just want to understand if you can use a virtual machine as a additional privacy tool and if yes, on what aspects would it have an impact (ip address, virus infections, fingerprinting, etc.)?
Thanks
When you're hosting a VM on your local machine, it may share the same IP as your host, as far as the outside world is concerned. Most hypervisors allow you to change how it obtains an IP address, but in typical configs it will only change on your local network, which is probably NATed behind a single address provided by your ISP. A VPN is a good way to change that, and you can configure that either inside or outside the VM, though ideally you'd no want to be sharing an IP with your host system.
Using a VM can help against fingerprinting because you can be running a different browser in a different OS in your VM than on your host system - but that instance itself can be tracked/fingerprinted, so it may be a good idea to rotate through a series of different configurations (or use a browser plugin that randomises some settings, such as reported browser version, OS, installed fonts, etc), and to throw away changes in your VM each time you use it, which will eliminate even the hardest of "supercookies" that might try to track you.
Unless your hypervisor is compromised (this has happened in the past, but it's rare), the VM itself will provide good protection from malware - for example Windows malware will have no effect on a Linux VM, and vice versa - and any malware that does infect your VM is contained by the sandbox that the VM provides - and you can simply reset it to return to a known-clean state, or throw it away and start again.
I ran into some trouble when I tried to ping my Ubuntu virtual guest from my Windows 10 host, but this solution did the trick.
I'm wondering what exactly is a "host-only-adapter" and why cant the I ping the virtual machine by default? How exactly does the virtual machine access the internet when I cant ping it?
As the name suggests, host-only is intended to create a new interface that is virtual and visible to the host and not in anyway connected to the physical interface that actually connects to the internet.
Itcan be thought of as a hybrid between the bridged and internal networking modes: as with bridged networking, the virtual machines can talk to each other and the host as if they were connected through a physical Ethernet switch. Similarly, as with internal networking however, a physical networking interface need not be present, and the virtual machines cannot talk to the world outside the host since they are not connected to a physical networking interface.
You might be wondering what the use-case for this would be.Think for example: one virtual machine may contain a web server and a second one a database, and since they are intended to talk to each other, the appliance can instruct VirtualBox to set up a host-only network for the two. A second (bridged) network would then connect the web server to the outside world to serve data to, but the outside world cannot connect to the database.
How it works
when host-only networking is used, VirtualBox creates a new software interface on the host which then appears next to your existing network interfaces. In other words, whereas with bridged networking an existing physical interface is used to attach virtual machines to, with host-only networking a new "loopback" interface is created on the host. And whereas with internal networking, the traffic between the virtual machines cannot be seen, the traffic on the "loopback" interface on the host can be intercepted.
The great thing about host-only networks is that the host itself sits on this network and so, upon proper config as in you link above, you can reach all the VMs.
Hope my explanation helps!
Well..I have found some third party application regarding sending data from com port to IP. but I have not found any basic tutorial regarding them. so can anyone help me with this? I have a GPS device which I will connect to my laptop through usb to serial adapter.Now I need to send that data from a laptop to another laptop on same network. Can I use putty to view that data in another laptop(receiver)? Is virtual serial port driver meant for this kind of application?
If you do not want to write your own tool for it, you can simply use ncat and set up a daemon that reads piped data from one process and broadcasts it to all connected clients.
If you want something that reads the data from the serial port and then transmits it to clients, you'll need to write a server application that accepts connections and sends data around, but there's entire books on this. It should be easy to do for your purposes as written here, but it depends on the amount of control you need.
Alternatively you can use a virtual serial port application as you had mentioned, which might be the easiest route. The two devices will need to be on the same network unless the application supports TCP based virtualization instead of the common Ethernet based implementation.
This Python script works very well as a free "device server". Just enter the serial port configuration and the IP address and port information.
https://github.com/jaredly/pydbgp/blob/master/symbian/serial_tcp_redirect.py
This can work on both Windows and Linux.
You need pyserial.
You can always try using stand alone hardware such as the SENA LS100 device server.
I want to detect all devices in a LAN which have IP: 10.x.x.x Mask: 255.0.0.0.
I first wrote a synchronous ping program to ping IPs one by one, but it's tooooo slow.
Therefore I improved it by using asynchronous ping, then it's much faster.
Now I can use it to detect 10.x.0~255.0~255 in an acceptable time.
But it still use tooooooooooooo long time to detect all the IPs 10.0~255.0~255.0~255.
Is there any method/protocol that can just broadcast one message and let all devices in a LAN to respond, so I can detect all the devices?
(either Ethernet broadcast or UDP/IP broadcast or any other broadcast.)
(I've researched ARP & ICMP but haven't find suitable methods.)
Or any other method even don't need broadcast?
I just need to detect all the devices, any method is OK.
Not sure if it's what you are looking for but you can go in command prompt and run the command:
arp -a
I recommend "Angry IP Scanner" http://angryip.org/
It is fast, detects all devices in a given ip/netmask.
Angry IP scanner is a very fast IP address and port scanner.
From site:
It can scan IP addresses in any range as well as any their ports. It
is cross-platform and lightweight. Not requiring any installations, it
can be freely copied and used anywhere.
Angry IP scanner simply pings each IP address to check if it’s alive,
then optionally it is resolving its hostname, determines the MAC
address, scans ports, etc. The amount of gathered data about each host
can be extended with plugins.
It also has additional features, like NetBIOS information (computer
name, workgroup name, and currently logged in Windows user), favorite
IP address ranges, web server detection, customizable openers, etc.
I want to communication between two different android phone via USB. I look at Google SDK guide I don't know how can i do.Somebody can give me some suggests ? Thank you very much !
The USB-Standard requires to work as host-client-mechanism. This means in particular, that you usually have a host-controller (for example inside your PC) which a client (USB-drive, MP3-player, mobile phone) can connect to.
The host is responsible for negotiating and establishing a connection. If you want to connect two clients with each other, one of them must Support USB-On-The-Go to serve as a host with limited capabilities.
From Wikipedia
The design architecture of USB is asymmetrical in its topology, consisting of a host, a multitude of downstream USB ports, and multiple peripheral devices connected in a tiered-star topology. Additional USB hubs may be included in the tiers, allowing branching into a tree structure with up to five tier levels. A USB host may implement multiple host controllers and each host controller may provide one or more USB ports. Up to 127 devices, including hub devices if present, may be connected to a single host controller.[20][21] USB devices are linked in series through hubs. One hub—built into the host controller—is the root hub.