Re: Long distance links
Rohit,
There is a world of difference between 50 ms signal restoration and dispatching
personnel and a truck to do link problem determination. In between the two, you will
find numerous price points and associated service level guarantees. I am simply
pointing out that 10 GbE doesn't require all of SONET OAM&P to be successful and very
cost effective as a WAN transport. Given that the 802.3 committee is educated as to
what the REAL requirements for managing a WAN transport are, it will come up with a
very cost effective solution.
Passing Ethernet traffic to SONET for WAN transport is an existing solution which does
not require 802.3 activity. Transporting Ethernet directly over a WAN DOES require
802.3 activity. Understanding all the ins and outs of SONET/OAM&P and then leveraging
the best features for inclusion into the Ethernet architecture are some of the first
steps.
Best Regards,
Rich
--
Rohit Mittal wrote:
> Rich et al,
>
> One of the things you need to consider is that SONET has extensive error monitoring
> "built-in" the overhead to allow speedy detection of failures before they degrade
> to serious levels. SONET provides rapid fault isolation.
>
> Now, if you use TCP/IP for the same tasks, you are going to add latency etc.
> because the frame/data will have to pass through many layers before any fault is
> detected. That is the problem in moving up the protocol stack.
>
> For instance, SONET allows less than 50ms time for signal restoration (due to cut
> fiber etc.). I do not see anything in Ethernet which can provide equivalent support
> - maybe Far end fault detector but doesn't that takes a long time to detect?
>
> IMO, the best solution is just to encapsulate ethernet frames as data bits in a
> SONET frame. That way SONET can provide the management features for preventing
> expensive mantainence and Ethernet can travel as is. Am I overlooking something?
>
> Rohit Mittal
> Engineering, Microlinear Corp.
>
> > Mark,
> >
> > I believe you're on the right track insofar as digging to the root of the
> > management issue. The fact of the matter is that Ethernet does it one way, and
> > SONET does it another. My sense is the same as yours: "...instead of
> > transporting management info on dedicated
> > circuits, use TCP/IP and packets. It's the histroric trend, moving up the
> > protocol stack."
> >
> > I have asked numerous questions over this reflector trying to get at the core of
> > requirements for WAN management. I've seen no responses to those questions. BTW,
> > I'm sill very much interested in hearing the responses to these questions.
> >
> > Without knowing the requirements for SONET WAN management, I have to believe
> > that Ethernet Management, ULP (e.g. Ping, SNMP, Browser) management mechanisms,
> > Etherenet PHY capabilities for determining things like the BER of each link,
> > represent sufficient architecture to implement WAN management equivalent or
> > superior to that of SONET.
> >
> > Best Regards,
> > Rich
> >
> > --
> >
> > "Gerhold, Mark" wrote:
> >
> > > All,
> > >
> > > It sounds as if one of the biggest issues here is with the optical
> > > repeaters. If I understand correctly, Sonet repeaters are instrumented so
> > > that the administrator can isolate problems without sending out a truck.
> > >
> > > Consider using a 2-port "LAN" switch instead of a repeater. Switches today
> > > provide lots of remote maintenance features, including
> > >
> > > o Ping (for I'm alive)
> > > o SNMP (for tons of performance statistics, and alarms)
> > > o Browser management (for ease of use)
> > >
> > > With a switch, instead of transporting management info on dedicated
> > > circuits, use TCP/IP and packets. It's the histroric trend, moving up the
> > > protocol stack.
> > >
> > > Here's a question on a similar vein. Are WDM amplifiers instrumented to
> > > isolate BER problems? I thought they did optical amplification. Capturing
> > > BER info sounds tough.
> > >
> > > Thanks,(signing off)
> > >
> > > Mark Gerhold
> > > Unisys
-------------------------------------------------------------
Richard Taborek Sr. Tel: 650 210 8800 x101 or 408 370 9233
Principal Architect Fax: 650 940 1898 or 408 374 3645
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