[j-nsp] Hyper Mode on MX

[Saku Ytti]

Hey Michael,

> I have used successfully used hyper mode on MPC4E in M2K for a few years with little regrets.   I chose to do this as I didn't have the equipment to do line rate testing and I do a significant amount of counters on untrusted ports.  As others have suggested, you need to know feature limitations.  We certainly do .1q as well as double tagging so the vlan padding feature is not what you think it is.

What do you and Franz think it is? What I think it is

a) IP packet comes in to a router, and the packet is 41B or smaller
b) router sends the IP packet out via VLAN encapped interface, adding
VLAN to the 41B, for packet of 45B
c) 45B is invalid ethernetII payload size, frame may get dropped in L2 transport

I read hypermode as victim of Trio's success. Juniper has been able to
use same microcode for over decade now. Obviously after 10 years of
development any code base is in dire need of spring cleaning. But you
can't fix code without breaking code. So I think hypermode is just
Juniper's strategy to rewrite Trio microcode and pay up some technical
debt they have, but in a way that they release it to the market
staggered, without single flag day.
You could say Cisco is doing the same right now, because in ASR9k
history first time are introducing non-microcode compatible lookup
engine, forcing them to rewrite all forwarding plane code. Just JNPR
isn't forced to do it, they just choose to do it.

-- 
  ++ytti