Cell Relay Archive

[zsquad@my-deja.com]

In article <8j714h$rv1$1@nnrp1.deja.com>,
  Thomas Frieling <thomas.frieling@experteach.de> wrote:
> In article <8j6l7e$jcg$1@nnrp1.deja.com>,
>   zsquad@my-deja.com wrote:
> > HI.
> >
> > Can someone explain the usage of AIS and RDI in an ATM environment.
> >
> > On a oc3 port there is an RDI light, does that indicate a problem is
> > being reported from the router all the way at the other end of  the
atm
> > line?  or is it from an intermediate switch, and what does this
mean.
> >
> > (...)
>
> Hi,
>
> the RDI-light normally says that there is a SDH/SONET failure - layer
1.
> It occurs when only the receiver fiber is connected properly. An ATM-
> switch can be configured to generate special "OAM"-cells that carry
the
> information of an occurred AIS or RDI along the ATM-connection.
> Assume an ATM-connection going across six ATM-switches between two
> Routers. If now somewhere between the 3rd and the 4th switch a SONET-
> error occurs (due to a defective interface, a broken line or whatever)
> the ATM-switches adjacent to the damage receive nothing or a SONET
AIS/
> RDI and generate OAM-cells of type AIS (upstream SONET-error
information
> is carried downstream the ATM-connection) or RDI (reverse). Upon the
> reception of an AIS-cell the end station (here your routers) will
> transmit an OAM-cell of type RDI on the same connection. The OAM-cells
> appear in the statics menus of the end stations.
> There are some specific configuration options about the OAM fault
> management but I hope this helps.
>
> Thomas Frieling
>
> (These are all my opinions and they do not necessarily math those of
my
> employer.)




Thanks for the informative response.  I do have an additional
question.  You mention that the downstream router tx an OAM with RDI
back upstream, does SONET send any RDI back upstream as well?  using
the G1 byte of the POH?  (or is it just strictly using the F5 error
indication.

Thanks.







>
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>


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