[c-nsp] T3 or Ethernet delivery?

[Ryan Hughes]

Generally my experience with Ethernet handoffs has been hit or miss
depending on what the carrier is delivering for the hand off - I've dealt
with some gear as you alluded to that doesn't down the CE hand off when the
circuit goes which turns into an interesting game of routing protocol timers
and EEM/IP SLA for neighbor tracking.

I've also run into situations where its best to traffic shape the port to
the CIR you're getting the provider on sub-rate Ethernet hand offs (you're
only paying for 45mb and you negotiating the physical to a gig with their
gear).

But yeah - the price and cost saving of not needing certain interface line
card for hand off is undeniable and has to be taken serious.

Ryan

On Wed, Apr 8, 2009 at 8:54 AM, Gert Doering <gert at greenie.muc.de> wrote:

> Hi,
>
> On Wed, Apr 08, 2009 at 12:14:52AM -0700, Seth Mattinen wrote:
> > How do you detect a "down" condition on Ethernet? My experience is that
> > the interface could be up/up because Ethernet doesn't know about
> > anything further down the line and ends up throwing packets into a
> > magical black hole. Or worse, secret packet loss.
>
> Run a routing protocol over it.
>
> [..]
> > With a T3 I can be fairly certain that if there aren't any alarms that
> > my end is happily talking to the other end. How does one accomplish the
> > same with Ethernet? A periodic "ping" seems rather ambiguous as a health
> > check.
>
> Not necessarily so - even on a T3, you can have bad cables going just
> one way, so you might have packet loss in your transmit direction.  The
> provider would see (CRC) errors, but you might not see anything.
>
> So you'll need to run ping...
>
> (And yes, I know how you feel.  But the price difference between the
> gear for SDH 2.4 Gbit equipment vs. 2 x 1Gbit ethernet links was so
> overwhelming that we decided to go for ethernet... and for the same
> price, we even got *two* links, so "no single point of failure")
>
> gert
> --
> USENET is *not* the non-clickable part of WWW!
>                                                           //
> www.muc.de/~gert/ <http://www.muc.de/%7Egert/>
> Gert Doering - Munich, Germany
> gert at greenie.muc.de
> fax: +49-89-35655025
> gert at net.informatik.tu-muenchen.de
>
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