Cell Relay Archive

[Kenny Speer <kenny.speer@att.net>]

Yes, SONET uses the Z7 byte in VT's, the G1 byte in STS POH, and the M0, M1,
and K2 bytes in the LOH.  The AIS is a direct path failure resulting from 10
consecutive UAS or a LOS.  Every NE in the SONET infrastructure will send
back upstream both REI or RDI depending on the Alarm received.  If the
far-end receiver fails then you would see a FERF (far end receiver failure).
By using the path, section, and line indicators with the various alarms and
error indicators it is relatively simple to determine the source of
degradation or a failure.

If you are receiving RDI at your router then I would assume that it is being
generated from the router at the far end.

Hope this helps, I may have re-stated some facts presented by Tom.

Kenny

zsquad@my-deja.com wrote:

> 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.
>
> >
> > Sent via Deja.com http://www.deja.com/
> > Before you buy.
> >
>
> Sent via Deja.com http://www.deja.com/
> Before you buy.