[Bro] Checking symmetric traffic using bro

[Azoff, Justin S]

> On Apr 21, 2017, at 7:32 PM, Zhi-Wei Lu <zwlu at ucdavis.edu> wrote:
> 
> Hi Bro experts,
>  
> We are newbie of bro and  are in the process of testing a bro setup using Arista 7150 to split traffic using symmetric hashing, sending them to bro cluster. Could bro tell how well the symmetric hashing mechanism is working? What log files/stats shall we look at to discern this information?
>  
> Justin at bro IRC channel suggested this script
> https://gist.github.com/JustinAzoff/446d0abba2c6dd8ff242#file-conn-peer-bro
>  
> This adds peer (worker-x-y) information at the end of conn.log lines, in our case, we have a single bro server with 10 bro workers running on it, this would tell how well bro divide the traffic it received and send to individual workers, is that right?
>  
> What I am interested in is whether the Arista 7150 split traffic properly so that bro downstream could tell how well or bad traffic was split on Arista?  Is that possible?
>  
> Thank you very much and have a nice weekend.

I'm a bit confused.. if you only have a single server the switch isn't splitting the traffic at all.  Symmetric hashing is only relevant if you have more than one server.

For what it's worth, Arista switches in tapagg mode handle symmetric hashing perfectly.


-- 
- Justin Azoff