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srcvirus / micro-nf-datapath

DPDK-based datapath for stitching microservices to create network services
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Switch in Tembo clusters always broadcast frames #2

Open anthonyaje opened 6 years ago

anthonyaje commented 6 years ago

Seems like the switch we use in Tembo cluster always broadcast every frame generated by dpdk pktgen to other machines connected to the switch. We suspect that the switch can't learn a new mapping from a port to mac, due to the destination node not replying a correct respone frame for the switch to create a forwarding entry and stop broadcasting.

We are thinking of 2 work-arounds:

  1. Ask Lori to manually configure the switch to bind the ports to MACs.
  2. let the destination node craft a response frame so that switch can learn thje mapping.
srcvirus commented 6 years ago

Let's go with option 2. Essentially we have to write something like an ARP responder. When NIC classifier receives a broadcast frame it will send it to another muNF that will take care of crafting a response (only the destination node will send a response, the other nodes will silently drop it).

baizhenyu commented 6 years ago

After I searched a bit on Google, It seems you were correct. No magic response packet required to update MAC table in the switch. As long as the receiver node send back a packet with valid src and dst MAC, the switch will learn the mapping and update MAC table. However, this should be manually verified by experiments.

anthonyaje commented 6 years ago

@baizhenyu in that case, what I was speculating earlier tonight was actually works! We can try sending a tiny rate of Tx on the port that is receiving so that the switch receive correct MAC infos and thus learn the mapping. You wanna try?