Kaushik, thank you for your detailed answer. I was not aware that it is possible to oversubscribe the communication channel. Let my try to describe this behavior in my own words:
The nodes have a shared bandwidth of 57k. The communication pattern I use is
request-response. If the channel is over-subscribed and node A uses all the
available bandwidth, data sent by node B would get dropped because there is no
more bandwidth available.
How can I introduce oversubscription? Here are my configuration files:
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE nem SYSTEM "file:///usr/share/emane/dtd/nem.dtd">
<nem>
<transport definition="transvirtual.xml"/>
<mac definition="rfpipemac.xml"/>
<phy>
<param name="fixedantennagain" value="3.0"/>
<param name="fixedantennagainenable" value="on"/>
<param name="bandwidth" value="25000"/>
<param name="noisemode" value="outofband"/>
<param name="propagationmodel" value="2ray"/>
<param name="systemnoisefigure" value="4.0"/>
<param name="subid" value="2"/>
<param name="txpower" value="46.99"/>
</phy>
</nem>
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE mac SYSTEM "file:///usr/share/emane/dtd/mac.dtd">
<mac library="rfpipemaclayer">
<param name="enablepromiscuousmode" value="off"/>
<param name="datarate" value="57600"/>
<param name="jitter" value="0.10"/>
<param name="delay" value="0.7"/>
<param name="flowcontrolenable" value="off"/>
<param name="flowcontroltokens" value="10"/>
<param name="pcrcurveuri"
value="file:///usr/share/emane/xml/models/mac/rfpipe/rfpipepcr.xml"/>
</mac>
Thank you and best regards
Thomas
> Am 11.04.2017 um 17:31 schrieb Kaushik B. Patel <[email protected]>:
>
> Thomas, either the RF-Pipe or TDMA model will support what you are tying
> to do.
>
> 1. For the RF-Pipe, a few items that are useful to understand:
> A. You can configure and dynamically control the transmit data rate
> allocated to each node via the "datarate" parameter. So if you have a
> total of 57kbps available between the two nodes, you can split the total
> available rate equally between the two nodes by setting datarate="27k".
> Since the "datarate" parameter is run time modifiable, you can also
> change the allocation during you experiment as required. Note: You can
> also oversubscribe by allocating more than 100% of total bandwidth which
> would introduce loss since in theory both nodes would be transmitting at
> the same time. The amount of loss experienced can be based on
> percentage of over subscription and manged via the PCR curves.
>
> B. Managing delay on the link is also configurable and run time
> modifiable via the "delay" and "jitter" parameters.
>
> C. Introducing loss on the link is controlled via the Packet Completion
> Rate curve. You can define your own curve or use the default curve file
> that comes with the model.
>
> 2. The TDMA model gives you similar ability as above but via the use of
> a TDMA schedule. The one thing the TDMA model supports that RF-Pipe
> does not is the concept of packet fragmentation which may be important
> to you given the size of the pipe you are emulating.
>
>
> Kaushik B. Patel
> Adjacent Link LLC
>
>
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