On Thu, 11 Jun 2020 at 18:32, David Sinn <dsinn@dsinn.com> wrote:

However if you move away from large multi-chip systems, which hide internal links which can only be debugged and monitored if you know the the obscure, often different ways in which they are partially exposed to the operator, and to a system of fixed form-factor, single chip systems, labels fall apart at scale with high ECMP. Needing to enumerate every possible path within the network or having to have a super-deep label stack removes all of the perceived benefits of cheap and simple. The arguments about IP lookups being slow is one best left to the 1990's when it was true. Fixed pipeline systems have proven this to be false.

It continues to be very much true. IP lookups require external memory, which takes SERDES, which could be used for revenue otherwise. IP lookups are slow, expensive and complex, fundamentally, no amount of advancement will change this fundamental nature. Sure we can come up with all kind of implementations which bridge the gap, but the gap is there. If we take say JNPR MX, your lookup speed isn't limited by the instruction count on the PPE, the PPE spends most of its time sleeping, when the platform is fully PPS congested, the PPE is waiting for the memory to return! -- ++ytti