I want to know what's the difference between CDR and XDR.When I read articles i found CDR(Call Detail Record )and xDR(x Data Record),but i don't understand the difference between them.Can someone tell me what's the difference between them and thank you an advance
CDR or Call Detail Record is the voice channel. XDR is the data channel. For example, one difference is that CDRs encode 2 phone numbers and two antennas (in and out) for a call, while XDRs only contain one antenna (the one you're connected to and downloading information)... no "out" antenna or "out" phone number is nedded. Another difference is perhaps that you're not measured in how many minutes you burn, but how many KBs you down/upload. There are more details, but that's the gist of it.
My two cents:
CDR is for old school voice calls (ISUP protocol for example). And is used on active switching equipment.
XDR is for any generic signaling (SMS, Mobility Management, Data session etc. incl. calls)
And for data there is UDR (User Data Record) which represents info about "internet" usage.
xDR contains all thing that mentioned (CDRS, EDR, ...).
they are relating to telecommunication industry
Related
I am new to this tech but I am close to the concept of Channel. I understand that the channel are ledgers within a bigger ledger( i.e. small chain specific to some users only within the entire blockchain). Based on this I have few questions.
Lets say there are retail markets where there is scope for negotiations in rate and hence each vendor can sale same thing to different people with different prices. So assuming that there are 1000 people and 1000 vendors possibly there could be many channels. How these are managed?
I understand that the blockchains are linear data structure (unless two blocks are created simultaneously, there is a word for this but I forgot it), If I have to access previous data for certain user. How efficient it is going to be for such operations? i.e. take an example of bank credit card transactions. If I want to see all my transactions for last 5 months. How efficient it is going to be?
I am not claiming that I am completely correct in my understanding but these things are bugging me.It would be very nice if someone help me clear these?
Thanks :)
Update
I have gone through this link it also talks about something related to my questions in below comments. i.e. related to businesses (questions private blockchain).
I like more the definition of channels as different blockchains using a common network or common parts of a network. It allows privacy and different organisation structures.
Yes, it could have possibly so many channels as vendor-people pair. Of course, it depends on which privacy you want to achieve.
If you want to access previous datas for previous operations, you have the possibility to have a state database running alongside the peers, which are a state representation of the linear structure. You can use LevelDB or CouchDB. CouchDB allows you to use complex rich queries to access your data.
ledger can only exists in channel. And the channel is composed of peers. the peers out of the channel cannot get access to the ledger data.
I am not sure what you mean by "Operation". You can create it and close it(this will be supported in later version) When you need it ,create it and you can close after use.
If the business is independent, you have to create so many channels. you just say vendor can sale same thing to different people with different prices. . each of them will be used for different scenario.
if you want to get access to the previous data, of course you can. But not maybe as efficient as you the bank card now. But this is doable. Now we use sdk to access. maybe later with more development of the sdk, more graphic tool will be developed, enabling it used as easy as possible.
for my Operating Systems Networking class, we must come up with a common paradign that is faced when developing operating systems and propose a solution to the paradigm. Some possible topics suggested in class were: Producer/Consumer problem, reader/writer problem and there was a third one, idk the name for it. It was something like this:
Protection of Private Data – When a user has personal or private data he must share with a network in order to get information, but doesn’t want his information to be released.
-If a user must request a server for information and must provide some private data, the user tells his OS to request the information by sending a series or an array of data to the server. Some are actual data and some are fake. The server responds, handling each set of data as a separate request, it then returns the results and the OS picks the right one.
Example:
1) Person A uses his phone which uses his GPS coordinates to locate the closest bank. The OS on the phone knows that if the GPS coordinates were to get out, this could be bad. The phone instead, sends a request to AT&T asking for the closest bank for the following locations: the actual location person A is at, as well as 3 other fake locations. AT&T has no way of telling which location is the true location and which are the fake ones and is therefore forced to treat each one as a separate request. The results are sent back to the phone and the phone uses only the result for the location that is correct.
Another problem one of my friends did last semester was DDoS. I was wondering if you guys new of any other problems,issues or paradigms that are still lurking about.
Thank you for your suggestions.
my graduate project is about Smart Attendance System for University using RFID.
What if one student have multiple cards (cheating) and he want to attend his friend as well? The situation here my system will not understand the human adulteration and it will attend the detected RFID Tags by the reader and the result is it will attend both students and it will store them in the database.
I am facing this problem from begging and it is a huge glitch in my system.
I need a solution or any idea for this problem and it can be implemented in the code or in the real live to identify the humans.
There are a few ways you could do this depending upon your dedication, the exact tech available to you, and the consistency of the environment you are working with. Here are the first two that come to mind:
1) Create a grid of reader antennae on the ceiling of your room and use signal response times to the three nearest readers to get a decent level of confidence as to where the student tag is. If two tags register as being too close, display the associated names for the professor to call out and confirm presence. This solution will be highly dependent upon the precision of your equipment and stability of temperature/humidity in the room (and possibly other things like liquid and metal presence).
2) Similar to the first solution, but a little different. Some readers and tags (Impinj R2000 and Indy Readers, Impinj Monza 5+ for sure, maybe others aswell) have the ability to report a response time and a phase angle associated with the signal received from an interrogated tag. Using a set up similar to the first, you can get a much higher level of reliability and precision if you use this method.
Your software could randomly pick a few names of attending people, so that the professor can ask them to identify themselves. This will not eliminate the possibility of cheating, but increase the risk of beeing caught.
Other idea: count the number of attendiees (either by the prof or by camera + SW) and compare that to the number of RfID tags visible.
There is no solution for this RFID limitation.
But if you could then you can use Biometric(fingerprint) recognition facility with RFID card. With this in your system you have to:
Integrate biometric scanner with your RFID reader
Store biometric data in your card
and while making attendance :
Read UID
Scan biometric by student
Match scanned biometric with your stored biometric(in the card :
step 2)
Make attendance (present if biometric matched, absent if no match)
Well, We all have that glitch, and you can do nothing about it, but with the help of a camera system, i think it would minimise this glitch.
why use a camera system and not a biometric fingerprint system? lets re-phrase the question, why use RFID if there is biometric fingerprint system ? ;)
what is ideal to use, is an RFID middleware that handle the tag reading.
once the reader detects a tag, the middleware simply call the security camera system and request for a snapshot, and store it in the db. I'm using an RFID middleware called Envoy.
I am writing my own MIDI parser and everything seems to be going nicely.
I am testing against some of the files I see in the wild. I noticed that a MIDI track never appears to have more then one note on at once (produces more then one tone). Is this by design, can a midi track require more then one note to play at once?
(I am not referring to the number of simultaneous tracks, I am referring to the number of tones in a single track.)
The midi files I have tested look like this:
ON_NOTE71:ON_NOTE75:ON_NOTE79
ON_NOTE71:OFF_NOTE71:ON_NOTE75:OFF_NOTE75:ON_NOTE79:OFF_NOTE79
Can it look like this?
ON_NOTE71:ON_NOTE73:OFF_NOTE73:OFF_NOTE71
How do I detect this alternative structure?
Yes. Playing more than one note at once is known as polyphony. Different MIDI specifications define support for different levels of polyphony.
See http://www.midi.org/techspecs/gm.php
The number of notes that can play at once is a hardware implementation detail. Your software should allow for any number of simultaneous notes to be playing at the same time. I suggest keeping a table of which notes are currently on so that you can send a note off for each one when playback is stopped. Ideally the table should have a count for each note that is increased when a note on happens and decreased when a note off happens. That way if a certain pitch has two note on events pending you can send two note off events. You can't know how the device you're communicating with will handle successive note on events for the same pitch so it's safest to send an equal number of note off events.
Yes. Both controllers and software can produce such events.
I'm new to networking in general and I read about this protocol called Aloha, and I would like to make a simple simulator for the Pure version of it.
Although I understand the concepts, I find it difficult to start.
Basically we have a N senders in the network. Each sender wants to send a packet. Now each sender doesn't care if the network is busy or under occupation by some other sender. If it wants to send data, it just sends it.
The problem is that if 2 senders send some data at the same time, then they will both collide and thus both packets will be destroyed.
Since they are destroyed the two senders will need to send again the same packets.
I understand this simple concept, the difficulty is, how to modulate this using probabilities.
Now, I need to find out the throughput which is the rate of (successful) transmission of frames.
Before going any further, we have to make some assumptions:
All frames have the same length.
Stations cannot generate a frame while transmitting or trying to transmit. (That is, if a station keeps trying to send a frame, it cannot be allowed to generate more frames to send.)
The population of stations attempts to transmit (both new frames and old frames that collided) according to a Poisson distribution.
I can't really understand the third assumption, how will I apply this probability in aloha?
I can't find a single code online in order to get an idea how this would be done...
here is some further information on this protocol:
http://en.wikipedia.org/wiki/ALOHAnet#Pure_ALOHA
I think you have to split the time into intervals; in each interval a certain number of stations attempts to transmit. This number is the number of events occurring in a fixed interval or time according to http://en.wikipedia.org/wiki/Poisson_distribution.
You have to model it according to the Poisson distribution.
My 2 cents, hope this helps