I am trying to build a ryu application with starts and tries to get the owl topology. Therefor I’m using the get_link and get_switch function from the ryu.topology.api. Getting the switches is no problem but the list of links is always empty.
I tried using the get_all_link as well but the result is the same.
So far I found a lot of examples were they use those functions but none of these work with my set up.
Here are some examples i tried:
https://github.com/Ehsan70/RyuApps/blob/master/BasicTopoLearner.py
get_all_link(self) outputting all possible LINKs for a topo
My Ryu version is 4.32 and Im using the tree topology from mininet
Cheers and thanks for your help
You have to enable the processing of lldp packets by the controller using the --observe-links option when starting ryu.
Do
ryu-manager --observe-links your_ryu_app.py
Also if you try to get the links at the time mininet is building the topology you may get nothing. So try to put a timer to delay the get_all_links method, or try polling the switches using a monitor thread (see traffic monitor in Ryubook)
Related
I am trying to set up a potentiostat Xtralien by Ossila with LabView.
The way the instrument works in a string-in, string-out, so far so good.
The built-in code examples that are provided by the manufacturer contain firstly a string-in, string-out LabView program and secondly a preliminary console to record an I-V sweep (https://www.ossila.com/pages/basic-xtralien-commands-in-labview, https://www.ossila.com/pages/xtralien-x100-command-list). In the string interface, I can enter 'CLOI hello' and the device responds 'hello world', so far so good. If I proceed any further and send i.e. a 'smu1 measurev' command connecting to some photodiode, I just receive a near-zero value back, setting 'smu1 set voltage 0.5' or similar does not lead to an output voltage either. Running the sweep program over said photodiode gives noise in the µA range.
EDIT: All involved hardware components were double-checked.
Where am I doing something wrong? Is the error arising from communication errors or...? Has someone experienced this so far?
Received the answer from the Ossila support. The Xtralien X200 drivers were recently updated (http://files.ossila.com/source-measure-unit/Ossila-X200-SMU-Instr.zip), and you need to switch on each SMU channel sperately. This was implemented in a subVI in the Instrumentation -> X200.
Hope I helped all who get a similar problem in the future!
I'm trying to get the Watson Visual Recognition to run client side by using express-browserify with reference to the node-sdk for watson-developer-cloud. The VisualRecognitionV3 makes use of the fs package hence I get the fs.existsSync error when I'm trying to call it from the client-side as the browser doesn't know which filesystem to use. My question is how do I go about creating a so called 'abstraction layer' as I am restricted to using the express-browserify package for cross origin calls.
This thread is pretty helpful in shedding some light but I'm not sure where to start regarding the 'abstraction layer' or if there are any other solutions. Also, would something like socket.io work for this? I've linked a clone of the directory here as it seems less clunky than pasting the multiple portions below.
The repository can be cloned and just requires a personal iam_apikey with relevant launch configuration. Appreciate any pointers. Thanks!
I didn't manage to sort this out with express-browserify due to the require(fs) from browser issue but I was able to get it running using the express-ws package
I have chipKit uC32 (PIC32MX340F512H) ,chipkit BasicIOShield and PICkit3
programmer all from the Microchip.
I'm using MPLABX IDE.
Since I'm very new to this so I didn't know where to start I have searched and look at the web and find only tutorial which using MPIDE which I'm not allowed to use in my project.
I have read the Reference manual and Data sheet for and make test project but any way the uC32 Board refuse to recognize the BasicIOShield and I was unable to connect this two together.
Any tips and link would be great. Thanks in advance.
In the Basic IO shield Reference manual stated that you should follow some step in order to make the ChipKit to talk to the basic IO shield.
Power on sequence
Apply power to VDD.
Send Display Off command.
Initialize display to desired operating mode.
Clear screen.
Apply power to VBAT.
Delay 100ms.
Send Display On command.
Power off sequence
Send Display Off command.
Power off VBAT.
Delay 100ms.
Power off VDD.
The shield is using SPI2. The following registers are used
RF4, RF5, RF6 and RG9
Also you must change the jumper in the uC32 from LED4 to JP4 and JP8.
in the Appendix B of the reference manual of the basic IO shield is an example code which is useful.
Currently i'm working on a security monitoring app that continuously monitor new processes created.
For that im using wim and event watcher, witch works fine in VB.NET.
But there are 2 features that im missing.
I need to monitor process API calls, and I've been searching the web like mad, and come up empty.
Basically i need to monitor process WaitForSingleObject, LoadLibraryA, CreateProcessW and WriteProcessMemory. And registry access/changes as well.
Im hoping this can be done without a system wide hook, but form what i can find, it cannot be done via WMI.
So the question is, how to, and what can i do with managed code.
I'm gonna focus on the second point as i don't have experience on your first.
For checking if a process is signed i am using the sigcheck.exe from Mark Russinovich, because of the various methods it uses to verify files. Some are catalogsigned, some have the key embedded, there is iirc another weird method. There is no easy way to do it yourself. Had weird false detections with trying self-built methods to cover all possibilities. Hope that info helps
I am trying to write a small application usingwebrtc that can be used as a messaging/Chat application between 2 computers.
I see this:
http://simpl.info/rtcdatachannel/
and it is not working. any suggestions?
I wrote the simpl.info/rtcdatachannel example. It's only designed to show off data channels working within one page.
For a complete peer-to-peer messaging application, I suggest adding RTCDataChannel functionality to something like apprtc.appspot.com. You could also consider a readymade abstraction library like PeerJS or EasyRTC.
You might also want to take a look at the RTCPeerConnection/RTCDataChannel/signaling codelab I built.
In above example, from the trace log, the ice-candidates are generated, but they are either not exchanged between each other because of there may be problem in sending 'offer' or responding the 'answer'. Also above example works only in chrome( because of only webkitRTCPeerConnection is used, with mozRTCPeerConnection this can work on firefox also.
If you want to develope chat application for only text and not for the video chat, then you can use node-js & socket.io or websockets for this.
You may like :) following two libraries:
DataChannel.js / for webrtc data/text/file sharing (among multi-users)
RTCMultiConnection.js / for data as well as media (screen/audio/video/etc) sharing
Firebase.com is a "suggested" starting point for newcomers; that can be used for signaling. You just need to override "openSignalingChannel" and done!
You should use peer.js (https://github.com/peers/peerjs) or use peer chat (https://github.com/Hironate/PeerChat) if you want to do with node js.