Can one expect that all bus channels have unique NetworkHandleType identifier, that is that CAN channel and LIN channel can not have the same id? And can one expect that ids will be ordered and continuous, that is all CAN channel ids lie in the interval [CAN_STRT,CAN_STOP)? I hope my question does make sence, since I'm new to AUTOSAR. Sorry for my english, and thank you in advance!
The function BswM_CanSM_CurrentState will take as a parameter of network the ComM Channel Id.
A LIN channel and CAN channel will have different ComM channel ID's.
There is no requirement that ComM channel ID's start from zero and be continuous. But generally, one would configure the values starting from zero.
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Good day!
Please, help me understand how the Delay block works in AnyLogic. Suppose we deal with a multichannel transmission network.
The model has 2 sources. Suppose these sources generate packets every 1 sec. Packets from different sources have different priorities and need different quantities of resources to be served (it is set up with Priority and Resource_quantity parameters respectively). The Priority_queue in the model is priority-based. The proposed model put the packets into the channels in accordance with Resource availability in the channel. Firstly, it tries to put the packet to the first channel. If there are no available resources it puts the packet into the second channel. If there are no resources in both channels it waits (it is realized with Hold block).
I noticed that if I set delays in blocks delay1 and delay2 with static parameters (for ex. 2 sec) the model works ok. But then I try to calculate it before these blocks the model doesn't take into consideration it at all. And in this case, the model works without any delays.
What did I do wrong here?
I will appreciate any help.
The delay is calculated in Exit block and is written into the variable delay of the agent. I tried to add traceln(agent.delay) as #Jaco-Ben suggested right after calculation of the delay and it showed zero. In this case it doesn't also seize resources :(
Thank #Jaco-Ben for the useful comments.
The delay is zero because
the result of division in Java depends on the types of the operands.
If both operands are integer, the result will be integer as well. To
let Java perform real division (and get a real number as a result) at
least one of the operands must be of real type.
So it was my problem.
To solve it I assigned double to one of the operands :
agent.delay = (double)agent.Resource_quantity/ChannelResources1.idle();
However, it is strange why it shows correct values in the database.
As far as I unterstand BLE uses two 1-bit fields for applying sequence numbers to packets (SN, NESN). From my (admittedly basic) knowledge about (wireless) communication a 1-bit sequence number is perfectly fine as long as a sender does not continue sending data until the last message is acknowledged by the receiver.
Because of that it is trivial to understand how BLE works with a one-packet-per-interval scheme. However BLE allows multiple packets in a single connection interval. So far I couldn't find any information on how this scenario is handled without allocating more bits for larger sequence numbers.
Any pointers in the right direction on where I'm going wrong or where I can read up on this would be appreciated.
I am going to write a network device driver, which supports multiple channels.
Now, I am going to write the some counters (such as bytes/packets transferred) of this channel to sysfs.
For example, this device opens 8 channels, then, I would like to have sysfs like this:
/sys/devices/mynetdev/channel_0/
______________________________/bytes_egress
/sys/devices/mynetdev/channel_1/
______________________________/bytes_egress
/sys/devices/mynetdev/channel_2/
______________________________/bytes_egress
...
Questions:
How to create the attribute group so that I have one folder per channel?
Looks like I need to associate the attribute group before device registering. Then when do I update those attributes? Updating the attribute may impact the network performance?
How does the "attribute" work? For example, when user query the sysfs from cat command, does it issue command to driver to get attribute updated? Or my driver will keep updating the attribute and cat command just query the value?
Thanks!
set .modified field of iio_chan_spec to 1. Modifiers are specified using .channel2 field of the same iio_chan_spec structure and are used to indicate a physically unique characteristic of the channel such as its direction or spectral response. For example, a light sensor can have two channels, one for infrared light and one for both infrared and visible light.
I have read from an article that bit torrent uses uTorrent Transport Protocol.Also as far as I understood, if I am downloading a file using bit torrent, the different pieces can come from different peers. All these packets have the same connection-id. But how can I understand the order in which these packets arrived?
For an e.g., Let P1,P2 and P3 be the peers from which I can get my file. D1 be my system. Then first portion of the file came from P2, second from P1 and third from P3. Is there any way to find which part came from from which system so that I can reconstruct the file from the captured packets?
Thank You.
The order of the individual uTP packets doesn't matter. The uTP protocol takes care of reconstructing the order of the transported stream.
It's not necessary to know from which system torrent 'piece' messages originate to reconstruct a file. By utilizing the data in the metainfo for a torrent, and 'piece' messages per the bittorrent peer protocol it's possible to create the intended files within a torrent.
To avoid confusion, I think you will benefit from knowing that uTP is a level of abstraction below the peer protocol in use with each peer.
I want to scan the WiFi on b/g interface, and I want to sniff packets on each channel, by spending 100 ms on each channel. One of the biggest requirements I have is not to store the packets I get (because of less disk space), my application will parse the packets, retrieve Tx MAC and RSSI, and would construct the list (MAC, Avg RSSI, #Records) at the end of every minute, and then clear this list and start over again.
I've figured out two ways to do channel hop on linux:
Option 1: Use wi_set_channel(struct wif *, channel number) system call in C, and write the code in C to sniff all the packets
Option 2: Use linux command iw dev wlan0 set channel 4, and use any language like python+scapy OR C to sniff the packets
I'd like to know which is more efficient of the two, if at all, so that the delay/wait for WiFi interface to switch to a different channel is minimal. I suspect that this delay would mean loss of packet while the switch to a different channel happens, is that the case?
I would also like to know some of the other ways to solve this problem in linux.
Answer to your first question us straight forward, use Option1 and have two threads doing the work - one thread populating an in-memory circular buffer with packets collected from channels and second thread processing them in sequence. You can determine best packet discarding algo depending on the measured performance of processing thread and other factors if any.
As for the second question, I would go with the above for being in complete control on exactly how you can tune the algorithm rather than depending on canned processing tools.