packet aggregation

[student]

Hi,

I simulate a scenario where a set of nodes send data to a sever through a relay node. At a predefined period, I want to aggregate the received packets in the relay node before sending them to the server. Knowing that I use udp application and I use wifi to enusre the communication between nodes (I performed simulations with 802.11b and others with 802.11n), I want to know how can I perform aggregation of the received packets.

Thank you in advance for your help

[Sampath]

Would this help you? 

https://www.nsnam.org/doxygen/wifi-aggregation_8cc_source.html

Wi-Fi has two levels of aggregation. If your relay node is a Wi-Fi node you can simply use it

[student]

Hi, 

Thank you Sir for your reply. 

Yes, my relay node is a wifi node. If I understand the suggested code, it is suitable for 802.11n (and not for 802.11b), and aggregation is done at the MAC layer.

My relay node is configured as an udp server. I made some modifications to the udp-server.cc file where I scheduled transmission every period T after receiving a set of packets. Is it correct to create an aggregated packet with a payload size= n* (L+28), where n is the number of received packets during the period T, L is the payload size of each received packet and 28 is the udp/ip header size? If this solution is correct, is it correct to add an additional payload as a separation between every two consecutive aggregated packets to enable the final destination to read them? Is it correct to suppose the use of a compression header protocol to reduce the size of the aggregated data? 

If this solution is not correct, is it possible to schedule transmission every T period using the code that you proposed? Is there a separation between the aggregated packets and how to deal with the case of 802.11b?

Sorry for all these questions, but I am not sure about the feasibility of my idea.

[Sampath]

These things really depend on the MAC protocol in use. For instance, the Wi-Fi MAC protocol already has subframe headers to separate IP packets inside an aggregated packet.

https://www.nsnam.org/docs/release/3.18/doxygen/amsdu-subframe-header_8cc_source.html

I am not sure header compression is used in Wi-Fi. You might want to check it carefully.

[student]

Thank you sir for your reply. So, my implementation is false and I should make modifications in the MAC files if I want to schedule packet aggregation periodically. In the case of IEEE 802.11b, how can I treat this problem?