[c-nsp] FBF vs default route

[Adam Vitkovsky]

Hi Saku, all,

In order to route traffic to internet VRF one can use either default route pointing at Internet VRF or FBF to dictate which table will be used to perform the lookup.
Each of these comes with a certain performance tax and I’d like to figure out which method would be faster two lookups or FBF and one lookup?

Reading the TRIO papers the lookup “workflow” consists of all the features enabled and the complexity of the workflow dictates how many lookups into RLDRAM are necessary. And I believe that the overall lookup performance basically boils down to how many memory lookups are needed per workflow.

It could be that the queries to RLDRAM are bundled while the workflow is in progress and at the end the RLDRAM is queried only once
maybe even in a parallel fashion(remember there are 4 phy mem blocks), to retrieve all the info needed to modify the packet header or yield the egress LC.

However this can't be done if the workflow requires some information from RLDRAM in order to complete,
in that case RLDRAM would have to be accessed multiple times during the workflow waiting for data to be retrieved from RLDRAM and that would increase the lookup time significantly.

I'd like to understand the lookup performance vs. functionality trade-off on TRIO chipset and I wasn't able to find any info unfortunately.




adam


        Adam Vitkovsky
        IP Engineer

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