NFD

Sure. I agree with creating a new policy and making it a new default.

Sounds good to me, too. I will create a new cache replacement policy (probably named Fifo or PureFifo) where only has one queue with no priority for any Data packet.

What about the "lru" policy? Does it distinguish between fresh and non-fresh Data? (and shouldn't it be the default rather than a pure FIFO policy?)

What about the "lru" policy? Does it distinguish between fresh and non-fresh Data? (and shouldn't it be the default rather than a pure FIFO policy?)

LRU does not use Freshness. So, it meets our requirements and can be the default replacement policy.
However, I think we need to have a pure version of Fifo, anyways, and between FIFO and LRU, I think FIFO replacement policy is considered the one with the basic functions, with no fancy mechanisms.

LRU has nothing "fancy" while FIFO caching policy doesn't make much sense for any reasonable cache. So, I would strongly agree with Davide that LRU policy has to become a default, not FIFO (this was a copy of design from an ancient code).

FIFO caching policy doesn't make much sense for any reasonable cache

I am not sure what you exactly mean. FIFO and LRU are two different policies with their own pros and cons. It highly depends on the application that which one is better for it. FIFO (probably) is the simplest replacement policy (which is easier to analyze). This is the main reason I think FIFO is a better candidate to be the default one.

BTW, regardless of default policy, do we need the pure FIFO? Because I've already pushed the code to Gerrit.

Beichuan, thinks we do not need to implement FIFO replacement policy. I'll just make LRU the default replacement policy.