I'm working on a project that require a working similar to connecting 2 or multiple USB Internet Modems to just one PC and make them work all together at the same time, and i want to know if i can use 2 USB Internet Modems in just one PC and make them work simultaneously.
Thank you.
Combing multiple internet or WAN connection is definitely possible, although there are lots of caveats. Google '3G Multihoming' to see some more background.
There are actually relatively cheap ($50 approx) routers which will support load balancing over multiple WAN ports - look for Dual WAN or Multi-homming in the tech specs.
You can also 'trick' windows into using more than one internet connection - see some links below.
However, unless you use a service on the server side also to help split the loads, you need to be aware of some limitations:
If your use case has lots of requests that can run in parallel, as many web page downloads do, then this technique should work well.
If you are downloading a single large file in one request then it will likely not make much difference, although if it is smart enough to move all other request to another connection it may help a little.
Some links for Windows dual connection use (note I have not tested these personally):
http://www.wikihow.com/Combine-Two-Internet-Connections (be wary of the 'double speed' comment)
http://www.techkhoji.com/how-to-combine-multiple-internet-connections/ (see 'Method 2')
Related
I am trying to update a legacy system's sql solution to use the cloud.
The solution today involves a customer Windows SQL server installed onsite, then various machines are configured to connect to that IP Address / Port / Server Name. When they do connect the machines will set up any tables that are missing and regularly send their data. Data rates are low for an individual machine. Roughly one write request ever 10 seconds (it varies a lot), no more than 2-3k of information on each write request.
Moving this to the cloud is tricky mostly because each of the machines do not have a unique identifier. The good news is that we have the legacy machines connected to a IOT Gateway (Just think RPI) that knows a unique machineId. Furthermore the IOTG is a full fledge computer but not too powerful of one, and its Disk is an SD card.
New and Old Network Layout
So far I have had a few things fall on their face.
1) Setting the Machine to think the DB's IP/Port is that of the IOT Gateway. Setting up an Express server on the IOTG, listening, then injecting the unique id into the queries that I'd proxy up to the cloud. I may have had a bug, but for some reason I couldn't even see the requests coming in on the port. Even if I could I'd still have to figure out how to decode them. Shouldn't I at least be able to see these requests coming in?
2) Started looking into SQLite. The idea being to have SQLite listen on the port as an actual DB then have a process in the IOTG query data out of SQLite, append a unique ID, and then send it to the cloud. Unfortunately SQLite does not listen on a port.
I am starting to looking at just installing a whole SQL server on the device, but I'd really like to avoid that. I'm pretty sure its fairly large and writing to disk is not advisable for a small embedded system like I'm running.
Generally my questions boil down to:
1) Should I be able to see SQL Queries in an express server?
2) Should I be using a different tech? I failed to find a different more sql specific proxy.
3) Am I correct to think that the SQLite path is dead? Even if I could find a way to attach it to a port there is still not going to be any sort of response from SQLite when the clients try to make a connection.
4) Am I wrong to fear the local server? Diving into some documentation for making express work with DBs gets me to here: https://www.microsoft.com/en-us/sql-server/developer-get-started/node/ubuntu/ which suggests 4GB of memory, we're working on 0.5GB.
Any other thoughts on how to approach this would be great.
I'm in the process of creating a WebRTC 1-on-1 video chat.
I was told by one of my users that a competitor of mine (who also offers a WebRTC video chat) that if the connections gets bad (=pixelated video and choppy sound), the competitor asks the user if they allow the connection go through their own server instead of p2p.
What might be the reason why they offer users to do it via their own server? Do they use a different system (=not WebRTC?) then?
I thought that nothing could be better than p2p, so I don't understand what my competitors do in such a case where they offer such a workaround.
Thank you for any insights.
Using a server could give you a better experience for a few reasons.
If you are sending to multiple viewers you have to share your bandwidth between every receiver. When you switch to a server you only have to upload once (and then the server distributes the video to the receivers).
The network route to the server could be better then the P2P call. If you run your server in something like AWS the two users may have a better network path to the server.
The server could be doing signal processing on the backend. You have things like SVC and Simulcast, where the sender uploads multiple 'quality levels' to the server, and the server decides which one to distribute.
Unlikely (but possible) I have seen demos where some companies will use machine learning to improve video. I have never done it myself though!
These are all done via WebRTC and common use cases. My guess would be your competitor is using an Open Source SFU/MCU. Many projects exist that cover these use cases.
If I want to stress test a 'classic' client-server (desktop app <-> LAN <-> database server) Windows Forms desktop application to see how it performs when many concurrent PC users are using it, how should I go about it? I want to simulate many PC users concurrently going through a work flow, to see if it all stands up and at what point the system degrades unacceptably. I've looked at many test tools but they all seems to be skewed toward testing functionality or web app performance, which is quite different.
Clearly having many actual people on actual PCs is not practical, and lots of virtual machines on a few PCs is not representative either. 'Cloud' computing (EC2, Azure etc) looks promising but the documentation and pricing information all seems to be skewed towards mobile apps or web servers, again not the same (but that could just be presentation so I remain open to the idea). I need to be able to virtualise a small LAN of many client machines running the application and a database server.
Can anyone suggest how to do this, or recommend something?
TIA
IMHO the real question is - do you really need to do performance testing in your case? Consider this - where is your business and functional logic?
Performance testing of Desktop applications is oxymoron by itself. Desktop application is made to be used by one person at a time. So if getting a response takes 5 seconds, it will take (pretty much) 5 seconds no matter how many users are clicking the button. The only real thing close to your backend is the DB and they by design support serious asynchronous load. In case this is not enough - just make a cluster.
I have inherited an Access database that has linked SQL tables. I need to test the network traffic that is caused by the execution of the Db. I need to ascertain which parts of the system cause the most Network traffic and therefore are the slowest.
I am not an access guru so ive struggled doing what was suggested, which is : have Task Manager open at the Networking tab.
Then Step in into the app and looking at where there is a significant rise in Network traffic. But this seems rather unreliable and time consuming.
Does anyone have any ideas how I can achieve my goal in Access?
If you really need to analyze the network traffic then you should probably get to know WireShark well enough to do a capture that is filtered on the traffic between the client and the SQL server.
Other than the possible lag issues, has anyone tried this? What are the pros or cons associated with this?
A lot of times for me it's the limitations of the remote desktop connection, be it VNC or RDP or whatever. For examples:
My workstation has two monitors. Remotely viewing my workstation reduces it to one.
Lag is tolerable in the IDE, but not with anything image-heavy. Everything from photoshopping to web browsing is done locally, not on the remote machine.
Adding to #2, when splitting up tasks between the local and remote machine, there's that extra layer of getting the two to play nice together that adds just a little bit of overhead per task, which adds up to a lot overall. Something as simple as saving a file from the web browser and opening it in the IDE takes more steps.
(I may think of more and add them later.)
All in all, it's fine if the setup can be adjusted properly. In my experience, the companies I've worked for have defined their remote connection capabilities by the needs of someone other than the software developers, and thus leave us with little pet peeves that make the process just slightly more difficult than it needs to be.
Here is my take on it from my experiences
PROS: Single dev environment, only need to license one set of tools (if applicable)
CONS: The lag got the best of me. Typing to only have it show up 1 - 3 seconds later...sometimes, other times works great. In VS, the popup notifications sometimes take forever to display as well. Other cons would include if you have to share your desktop with another employee and possible moving files to/from the dev machine as RDP does not natively allow you to drag/drop files.
same as other posters - lag when using tools that affect screen painting for vstudio (resharper,coderush) is a real problem - some stuff involving the mouse (dragging grid columns) is very difficult to use
I'd add that about every 10-15 times when I go to log back in on the physical workstation at work, it takes the stupid thing about 2 minutes to finally succeed in refreshing the displays