[j-nsp] em0/em1 intreface

[Chuck Anderson]

fxp vs. em is just FreeBSD nomenclature for the type of device driver
used by the kernel to drive the hardware device.  There is no other
semantic meaning tied to "fxp" vs. "em" than that.  Some hardware uses
the fxp driver, some uses the em driver.

>From FreeBSD manual pages:

     fxp -- Intel EtherExpress Pro/100B ethernet device driver
     em -- Intel(R) PRO/1000 gigabit Ethernet driver for the FreeBSD operating system

On Fri, Mar 16, 2012 at 10:48:09PM +0200, Saku Ytti wrote:
> On (2012-03-16 22:21 +0200), Saku Ytti wrote:
> 
> Reread the OP and seems the implication of fxp->em was not ever made. Just
> fxp[12] -> em[01].
> So confusion was just mine. And indeed new REs uses 1GE/em[01] for internal
> signalling instead of 100M/fxp[12] (but all still use 100M/fxp0 for
> management)
> 
> > On (2012-03-16 12:05 -0700), Doug Hanks wrote:
> > 
> > > Depends on the platform, hardware, and routing engine.
> > > 
> > > At least on the MX the current RE uses em0 and em1.
> > 
> > This gives the impression in conjunction with OP that there is agreement
> > that fxp has been replaced by em. I'm not sure if that implication was
> > intended or not.
> > However that is not true, fxp are on-band dedicated management ethernet
> > (please JNPR, take page from CSCO and roll proper oob ethernet, like CMP).
> > While em are used for internal signalling.
> > And current RE model uses both, but obviously for different purpose.
> > 
> > > >Hi All, Just wanted to clarify my understanding in emo and em1 interface.
> > > >
> > > >In the latest hardware (REs/CBs), juniper have replaced he fxp1 and fxp2
> > > >interface with em0 and em1. Is this right?