Hi all,
       I have some doubts regarding differnt types of SDH errors,
there are basically 3 types of errors namely  section errors, line
errors and path errors could anyone help me out in what are the basic
differences of these errors and what are the significance of these
errors on on a typical layered communication N/W.

rgds,
prav

prav wrote:
> Hi all,
>        I have some doubts regarding differnt types of SDH errors,
> there are basically 3 types of errors namely  section errors, line
> errors and path errors could anyone help me out in what are the basic
> differences of these errors and what are the significance of these
> errors on on a typical layered communication N/W.
> 
> rgds,
> prav

Path errors are errors seen from anywhere throughout the circuit, 
remains in the path header all the way until termination at final 
destination.  Section  errors would be errors between two directly 
connected nodes.  Line errors are errors seen one "hop" away from the 
errored section.

So, for the sake of simplicity, let's say you have an unprotected linear 
STM16 system with a regenerator in the middle, and you are dropping STM1 
to customers at nodes 0 and 4:

0 - 1 - 2 - 3 - 4

If the westbound Rx begins to fail on node 2, you would see section and 
line errors at node 2's high-speed Rx, and line errors only at node 3's 
high-speed Rx.  Your customer at node 4 would see path errors on the 
STM1 path.  If there were any other nodes past node 4, they would see 
path errors on the STM1 as well.

Hello Prav,

You asked:

> I have some doubts regarding differnt types of SDH errors,
> there are basically 3 types of errors namely  section errors, line
> errors and path errors could anyone help me out in what are the basic
> differences of these errors and what are the significance of these
> errors on on a typical layered communication N/W.

First a correction, in SDH there are regenerator sections RS,
i.e. the actual fiber connection between two nodes. There
are multiplex sections MS, i.e. the link between two multiplexors
(that may pass a regenrator). A multiplex section consists
of one or more regenerator sections.
A path is the connection from the transmitting VC termination
point to the receiving termination point. A path consists of
one or more multiplex sections.

Regen. errors counted in B1 are used to locate the faulty
regen/multipl. (in practice hardly used)
Multiplex errors counted in B2 are used for PM on the MS.
they are used for MS protection switching, MSP, MS-SPRing.
VC errors counted in B3 are used for PM on the VC and for
path protection switching SNMP.

Cheers, Huub.

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                reply to hhelvooort with 2 'o's
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