I want to create mobile apps using webRTC APIs. My basic need is one-to-one video calling capability. Should I just use an open source webRTC server like openwebrtc? I want it to handle at least 5k clients. Is there any other option to fulfill my needs?
This question is very broad (and this isn't a proper answer), and is likely to attract very opinionated answers, and is also likely to be deemed as off-topic for Stack Overflow.
Having said that, if you can provide more information, you might get some reasonable opinions.
Please provide more information about what is important to you.
As WebRTC is a peer-to-peer system, scaling isn't a major issue. You need a signalling server of some kind to do call establishment. That work is over quite quickly, and then the two parties can continue the call without needing the server any more.
I don't have experience with openwebrtc, but I have used PeerJS, and found it to be quite good. It hasn't been updated in 2 years, but it seems to do the job pretty well, and is quite lightweight.
There are some commercial offerings around, but I question the value, as they leverage heavily from the open source components, and rely on the browsers for support. They are probably worth using if you want to do many-to-many video calling, as that is when you need a video server.
WebRTC is supposed to be easy, and it has been in the browsers for several years now (notably excluding Safari and IOS). It is a difficult area, and will take some time to master.
OpenWebRTC project is a reasonable option for a basic video calling native mobile app; its signalling server is only a basic demo, all written in JavaScript. As such, it should not crash on 5K simultaneous peer video connections.
But a real-world solution might require much more than this: TURN and STUN services, backup for the moments of hardware failure, load balancing, statistics and administration interfaces. Take security seriously: you should be able to cut out a spammer or other offender, in addition to protection against hackers.
Server software is that can help you will not necessarily cost much. See also https://stackoverflow.com/a/38810518/192373.
Related
I need a way for my web application to send push-notifications to the client side. Realtime is not a strong requirement, near-realtime is okay. I don't need anything fancy, just sending a string to the client every now and then, nothing more. What's really important is that the solution must be very simple and low-profile (performance-wise mainly). Could you give me advice on which framework to use?
Many people would say SignalR hands down, but I'm not sure about the performance part. It is not disqualified, I'll tell about my doubts below, and I'm also interested about any insights you may have about this, but the main question stays what I wrote above.
I read this article recently. What it provides is a long-running request pattern with only a few classes, a little IIS & async magic and nothing more. Even if you have an IIS connection limit of 200, it will barely use up any of those connections. Compared to this, SignalR is as complex and heavy-weight as a nuclear power plant. It comes with half a dozen different DLL's (like OWIN, which I haven't heard about before, and even after a bit of Googling, I can't figure out what it is). The performance wiki page of SignalR starts by suggesting to increase your concurrent request limit to a ridiculous amount. So I'm guessing it's not using the aforementioned "trick". I'm not exactly sure how bad that is, but in the light of that article, it doesn't sound good.
If you really want to push messages to the client, SignalR approach is very good. As far as I know it works with web-sockets. Try to digg this way. Here is some article for the beginning:
http://blogs.msdn.com/b/youssefm/archive/2012/07/17/building-real-time-web-apps-with-asp-net-webapi-and-websockets.aspx.
For mobile apps I would use great library PushSharp. https://github.com/Redth/PushSharp
With help of PushSharp you can send notifications to any mobile app: WindowsPhone, IOS, Android, Blackberry etc.
Please note: sending push notification differs from platform to platform.
Keep in mind approach with pinging server all the time and checking for new messages. It is probably the easiest way.
I use SignalR and toastr.js. SignalR can scale to thousands of connections. There are also native SignalR clients for iOS and Android (check out Signalr-ObjC).
Since noone answered about the resource requirements and my doubts about SignalR, which was the key question here, I'm accepting this as an answer: http://www.codeproject.com/Articles/27107/Scalable-COMET-Combined-with-ASP-NET .
Closed. This question does not meet Stack Overflow guidelines. It is not currently accepting answers.
Questions asking us to recommend or find a tool, library or favorite off-site resource are off-topic for Stack Overflow as they tend to attract opinionated answers and spam. Instead, describe the problem and what has been done so far to solve it.
Closed 9 years ago.
Improve this question
Can any one help me out to clear my doubts i am trying to implement an SIP application, I already have sip server setup and i have the username and password of my sip account.
Now I tried using PJSIP & SIPHON but somehow failed with lots of errors.
Then I tried with LinPhone and it worked fine.
Then copied the files from LinPhone project into my project and still working on it. (What else should I copy in my project to get going - i have copied the apple-darwin include & lib folder in my application)
I want to use G711(Both A and u) codec in the application and I can't find any header file's for that, please can any one suggest me how should I use G711 codec with the LinPhone Library in my Application?
Also can any one tell me that how many days it takes to cover up the SIP application without video functionality in it? (Audio Calls with GSM,Speex,G711 Codec's - only)
How many days will and Expert & Medium Level Developer will take to make app like this without any prior knowledge of any SIP app? (Any Rough idea according to you.)
Is there any other good open source library available to use easily to make an app like this?
Or any kind of a tutorial available? (Documentation of LinPhone is not upto the mark).
Am i going in the right direction?
Word of warning
This may sound like I'm trying to disuade you from persuing this endevor. Far from it, SIP is a fun protocol to work with (eventually) and it's very rewarding to see it all come together. You will enjoy a great deal of satisfaction at having gotten such a beast to work, and I wish you the best of luck in shaping it to your will! However, be prepared: SIP is a frustrating beast to work with.
The following timeline is based on my own experience, though I've shortened timelines somewhat due to there being two of you. Our dev cycle lasted nearly a year, but I was both the lead, and only programmer on the project, and that time includes all the work done on the UI, requirements coordination, planning, documentation, etc.
Week 1 & 2
SIP is a complex specification, with many extensions and peculiarities, especially relating to firewalls, forwarding, branching and joining. I would recommend you start looking up RFCs, and simply devote a good amount of time to reading the signalling specs, and any extensions you will need for your application, including at a minimum, the base specification, the SDP specification, and the ICE protocol specification.
That should occupy about a week if you're doing it right, and full time. For week 2, consider which extension specifications you'll need (presence indications, preconditions, conferencing, GRUU, etc) and spend the time to read those as well. Drill each other on them, it's a lot of information, and it's relatively complex in terms of how they all inter-relate to each other.
Break out the protocol analysers (Wireshark, etc) and see what the apps you have are doing on the wire. Having read the specs, you'll now be in a good position to understand why various SIP products have difficulty playing nice with each other, and, an idea of how to start working on your own app.
Week 3-6
Even with a decent toolkit, you will spend the better part of a month getting SIP to reliably do what you want it to in communicating signalling information, and writing the required infrastructure to respond to SIP signals. There are a crazy number of edge cases, and every pitfall you can imagine in concurrent processing is now magnified by the fact that you have three independent agents, some of whom will have very high latency, unreliable network connections, all trying to co-ordinate regarding the same transaction.
Don't take shortcuts, code, test, code more, look for faults and edge cases, and keep going. The RFCs help A LOT in understanding the problems you will run into, but some of it just has to be trudged through.
Week 7 & 8
Depending on the requirements for your application, just establishing the underlying connection between end-user agents will rightly occupy most of your effort to create a reliable product. You will, between the two of you, likely spend the next couple of weeks getting this part to work for the first time, and likely uncountable hours diagnosing edge conditions throughout the rest of the dev cycle of the app. Remember that there are edge cases here which require a media proxy, and a no-win edge case where the user is so badly firewalled that nothing can be done. Don't forget to handle them.
Week 9-11
At this point, your phones should (fairly) reliably connect to each other, depending on your experience and network knowledge, over fairly strict firewalls as well. The preconditions spec is very useful for decreasing perceived delay here, as you can hold off on ringing until the network layer has already connected. My experience will not inform the next layer (protocol) very well, as with Java, the media encoding and decoding was handed to me on a silver platter, aside from quicktime, which I had to do myself. I would chalk up a week or two for getting the protocols working nicely, and communicating protocol information reliably via SDP, but this may be a very optimistic estimate on my part.
Add another week if you've never worked with RTP/RTCP before, as while they're not complex per-say, properly responding to the feedback you get from RTCP can be challenging, and is somewhat of a dark art, though quite critical to ensuring optimal network utilisation and media quality.
Week 12+
Likely, at this point, you'll realise that one or another SIP product you want to be able to connect with, doesn't like your implementation, sometimes for reasons utterly inexplicable. If you need to support finicky products, you will spend the next few weeks to a month diagnosing why. If your product is proprietary, you probably don't care about this step, but it's also a way of double checking how badly you're mangling the spec. (We all do, so don't assume the test product you're using is correct either! Always double check!)
Additional
Bear in mind, the above is mainly intended as an estimate of how long it will take to get a well-written SIP/SDP/ICE based solution functioning, not the app using such infrastructure. UX is king in the iOS world, so make sure your app is compelling, and spend a LOT of time getting it right.
Even if
you use a library to make the coding easier, learn the underlying protocol! It will benefit you tremendously to understand why things work the way they do, and why the SIP universe is full of so many broken products.
The particular situation I am looking at is a Lighttp webserver embedded in a hardware device, similar to your home network router. So you can imagine, the footprint is small in both memory availability and processing power.
The two choices offered to me for developing the web application used to configure this device is either Django or Ruby on Rails. This is a telecommuncations device and the web application will configure settings on it as well as manage contact directories and the ability make outbound and accept inbound calls to and from the device. The application will also be used to upgrade the device.
The current interface uses a Flash front-end and php backend. But they want to get rid of both Flash and PHP.
So what is the prevailing opinion out here for this situation?
So you can imagine, the footprint is small in both memory availability
and processing power.
No chance you will see that with Python or Ruby. I think you need to provide more details for us to help you out.
Your question as asked ("prevailing opinion") is off-topic for stackoverflow (no definitive answer). However, I think what you're really asking is "are there any technical obstacles or benefits to using RoR vs. Django on a device with only XYZ resources?"
We can't answer that without knowing exactly what the limitations of your device are. It could be that neither framework is suitable, or either one would be fine (the latter is more likely, if someone has 'offered' you these as choices).
You may find answers to this question helpful:
Are there benchmarks comparing the respective memory usage of django, rails and PHP frameworks?
Closed. This question is opinion-based. It is not currently accepting answers.
Want to improve this question? Update the question so it can be answered with facts and citations by editing this post.
Closed 7 years ago.
Improve this question
I was recently approached by a network-engineer, co-worker who would like to offload his minor network admin duties to a junior-level helpdesk tech. The specific location in need of management acts as an ISP for tenants on its single-site property, so there's a lot of small adjustments being made on a daily basis.
I am thinking it would be helpful to write him a winform app to manage the 32 Cisco devices, on-site. I'd like to initially provide functionality which could modify access control lists, port VLAN assignments, and bandwidth limitations per VLAN... adding more to the list as its deemed valuable.
My initial thought was to emulate a telnet session with the network device; utilizing my network-engineer's familiarity with the command-line / IOS interaction. Minimal time would be required to learn Cisco IOS conventions, myself.
Though while searching for solutions, it appears that most people favor SNMP. That, or, their specific circumstances pushed them in the direction of SNMP.
I wanted to know if I've overlooked an obvious benefit of SNMP. Should I be using SNMP? Why or why not?
SNMP is great for getting information out of a Cisco device, but is not very useful controlling the device. (although technically, you can push a new config to a Cisco IOS device using a combination of SNMP and TFTP. But sending a whole new config is a pretty blunt instrument for controlling your router or switch).
One of the other commenters mentioned the Cisco IOS XR XML API. It's important to note that the IOS XR XML API is only available on devices that run IOS XR. IOS XR is only used on a few of Cisco's high end carrier class devices, so for 99% of all Cisco routers and switches the IOS XR XML API is not an option.
Other possibilities are SSH or HTTP (many Cisco routers, switches, AP, etc. have an optional web interface). But I'd recommend against either of those. To my knowledge, the web interface isn't very consistent across devices, and a rather surprising number of Cisco devices don't support SSH, or at least don't support it in the base license.
Telnet is really the only way to go, unless you're only targeting a small range of device models. To give you something to compare against, Cisco's own CiscoWorks network management software uses Telnet to connect to managed devices.
I wouldn't use SNMP, instead look at a little language called 'expect'. it makes for a very nice expect/response processor for these routers.
I have done a reasonable amount of real world SNMP programming with Cisco switches and find Python on top of Net-SNMP to be quite reasonable. Here is an example, via Google books, of uploading a new Cisco configuration via Net-SNMP and Python: Cisco Switch Upload via Net-SNMP and Python. I should disclose I was the co-author of the book referenced in the link.
Everyone's milage may vary, but I personally do not like using expect, and prefer to use SNMP because it was actually designed to be a "Simple Network Management Protocol". In a pinch, expect is ok, but it would not be my first choice. One of the reasons some companies use expect is that a developer just gets used to using expect. I wouldn't necessarily chock up bypassing SNMP just because there is an example of someone automating telnet or ssh. Try it out for self first.
There can be some truly horrible things that happen with expect, that may not be obvious as well. Because expect waits for input, under the right conditions there be very subtle problems that are difficult to debug. This doesn't mean a very experienced developer can't develop reliable code with expect, but it something to be aware of as well.
One of the other things you may want to look at is an example of using the multiprocessing module to write non-blocking SNMP code. Because this is my first post to stackoverflow I cannot post more then one link, but if you google for it you can find it, or another one on using IPython and Net-SNMP.
One thing to keep in mind when writing SNMP code is that it involves reading a lot of documentation and doing trial and error. In the case of Cisco, the documentation is quite good though.
SNMP isn't bad but it may not be able to do everything you need it to do. Depending on the library you use and how it hides the details of interacting with SNMP you may have a hard time finding the correct parts of the MIB to change and even knowing what or how to change them to do what you want.
One reason not to use SNMP is that you can do all the configuration you need using the IOS XR XML API. It could be a lot easier to bundle up the commands you want to send to the devices using that than to interact with SNMP.
I've found SNMP to be a pain for management. If you just need to grab a little data it's great; if you need to change things or use if heavily it can be very time consuming. In my case I'm comfortable with the CLI so a Telnet approach works well. I've written some Python scripts to perform administrative tasks on various pieces of network gear using Telnetlib
SNMP has quite a significant CPU hit on the devices in question compared to telnet; I'd recommend telnet wherever possible. (As stated in a previous answer, the IOS XR XML API would be nice, but as far as I know IOS XR is only deployed on high-end carrier grade routers).
In terms of existing configuration management systems, two commercial players are HP Opsware, and EMC Voyence. Both will probably do what you need. I'm not aware of many open source solutions that actually support deploying changes. (RANCID, for example, only does configuration monitoring, not pre-staging and deploying config changes).
If you are going to roll your own solution, one thing I would recommend is sitting down with your network admin and coming up with a best-practice deployment model for the service he's providing (e.g. standardised ACL, QoS queue, and VLAN names; similar entries in ACLs that have the same function for different customers, etc.). Ensure that all the existing deployed config complies with this BP before you start your design, it will make the problem much more manageable. Best of luck.
Sidenote: before you reinvent the wheel writing another service provisioning system/network management system, try looking for existing ones. I know quite a lot of commercial solutions of various degrees of flexibility/functionality, but I am sure there are quite a lot opensource ones.
Cisco has included menu options for helpdesk applications. Basically you telnet to the box and it presents a nice clean menu (press 1, 2, 3). For more info check this link:
http://www.cisco.com/en/US/docs/ios/12_2/configfun/command/reference/frf001.html#wp1050026
Another vote for expect.
Also, you don't want to allow configuration of your firewalls via either telnet or SNMP - ssh is the only way to go. The reason is that ssh encrypts its payload, and will not expose the privileged management credentials to potential interception.
If for some reason you cannot use ssh directly, consider connecting up an ssh-enabled serial console server to the firewall's console port and configuring it that way.
I need to deploy a Delphi app in an environment that needs centralized data and file storage system (for document imaging) but has multiple branch offices with relatively poor inter connectivity. I believe a 3 tier database application is the best way to go so I can provide a rich desktop experience with relatively light-weight data transfer needs. So far I have looked briefly at Delphi Datasnap, kbmMW and Remobjects SDK. It seems that kbmMW and Remobjects SDK use the least bandwidth. Does anyone have any experience in deploying any of these technologies in a challenging environments with a significant number of users (I need to support 700+)? Thanks!
Depends if you are tied to remote datasets. If you aren't dataset bound then SOAP would likely be a good choice. Or, what I've done is write my own protocol that is similar to SOAP in nature. This was done before SOAP was standard and I'm glad I did - this gives you the ability to control more of the flow of data. It's given that if you have poor connectivity then you will be spending time supporting it. It's very nice if it's your own code you are supporting versus having to wait on a vendor. (Although KBM and REM are known to be pretty good vendors.)
Personal note: 700 users in a document imaging application over poor connectivity sounds like a mess. Spend the money on upgrading connectivity as it'll be cheaper in the long run.
Both kbmMW and RO SDK offer binary format, which is more compact than SOAP format,specially you are working with documents.
RO sdk seems to offer more GUI tools to help you doing your services.
Also give a RealThinClient SDK a look, it's a lightweight remoting framework.
But what ever framework you go with, your design of work will make it fast or slow, I have some applications working on slow 128kb lines, and it's working perfect without any user complain, but I don't do a large transfer for files.
One thing to remember...its not the number of users, but the number of them using the resources at the same time that will be the issue. Attempt to develop your application "server stateless" if at all possible, this will allow greater flexibility in the long term if you find you have to add more servers to the pool to support your customer base. The hardest thing about n-tier is scaling beyond the first server...plan on that from the start. Each request should not know anything about a prior request...or at the very least the request should have a way of passing the context so the server can look it up in a session table or something.
Personally, I would recommend RemObjects. I have used it with good results.
I don't know if it's the very best / most efficient (glad you asked this question!), but I've had good results w/RemObjects SDK + DataAbstract. The latter made much of the plumbing details less involved, which was helpful. Still implementing, but so far so good.
If you really wanna go "low-bandwidth" use BSD Sockets API - that'll give you full control over what's being sent and there you can send as little information as you want. Of course then you'll have to implement all the tiers yourself, but hey - that's still an option :D