Increase Ring RX/TX buffers - Linksys WRT 1900ACS, TP-Link 1043ND

Hello, Greetings.

I need to create an experimental testbed using SDN OpenFlow enabled switches. Since large number of ports in the switches are not needed, OpenWRT/LEDE enabled TP-Link 1043ND, Linksys WRT 1900ACS meets the basic requirements of SDN enabled network that I wish to create.

My application generates a burst of packets (14 packets) every 1ms. When these bursty data is sent across a network or switches (TP-Link 1043ND - v3 devices) it works well if I have 2 devices in between. However, there are packet drops/failures when the number of switches is made to 3. The TP-Link 1043ND v3 devices support OpenWRT Chaos Chalmer 15.0.5.1.

Question 1: Ethtool -g produces RX/TX count as 512. - Does it mean the buffer is 512 bytes, or there are 512 buffers of a specific size?

Question 2: If this is size i.e., 512 bytes, how can I make it to 4096/8192? i.e., where should I shart and what changes to be made and compilation done?

Question 3: If I need to change for TP-Link 1043ND v4, (supporting atheros chipset) and Linksys- WRT 1900ACS v2 (supporting marvell chipset), Where do I start? I understand I have to change the NIC driver code.

Question 4: OVS version support in LEDE 17.xx is 2.5.0, whereas the latest OVS release is 2.9.0. If new OVS is to be enabled, what steps should I start with? I am leveraging the kernal data path of the OVS and would like to have a path with the least latency.

Your pointers will be much appreciated.

Thank you
manikantan
@abinmathew2