HO VC3 and "LO VC3" VCAT

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Hi,
 is it possible to have a single VCG with multiple SDH VC3 members,
where some of those members are HO VC3 and some of those members are
LO VC3 (i.e., carried in a VC4-TUG3)? It seems that VCAT should only
be concerend with the fact that all members are VC3s and use the H4
multiframe.

I assume it is true that I can put multiple SDH VC11 or VC12 into a
single VCG, and that some of those VC1x can be carried in HO VC3s and
others in HO VC4s. So by analogy I think the above should be possible
for VC3s.

Thanks,
Kevin
0
Reply kfowler 11/3/2004 6:59:40 PM

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Kevin wrote:

>  is it possible to have a single VCG with multiple SDH VC3 members,
> where some of those members are HO VC3 and some of those members are
> LO VC3 (i.e., carried in a VC4-TUG3)? It seems that VCAT should only
> be concerend with the fact that all members are VC3s and use the H4
> multiframe.

Theoretically it should be doable, but what type of system should support
this? In SONET you only have STS1-SPE (HO VC3), and in SDH only VC4-TU3-VC3
(LO VC3). I could imagine starting out with LO VC3, and have part of your
data routed through a SONET network after having been converted to HO VC3,
but usually you'd convert back to one standard before handling LCAS. Of
course there's the unlikely situation that your LCAS drop point is exactly
at the border between two types of networks (one SONET, and one SDH), but
even then I'd expect the data to be converted to one standard before
dropping it.

Regards,

Pieter Hulshoff

0
Reply Pieter 11/3/2004 10:20:53 PM

Hello Kevin,

You wondered:

>  is it possible to have a single VCG with multiple SDH VC3 members,
> where some of those members are HO VC3 and some of those members are
> LO VC3 (i.e., carried in a VC4-TUG3)? It seems that VCAT should only
> be concerend with the fact that all members are VC3s and use the H4
> multiframe.

Indeed VCAT is only concerned with the fact that all members have the
same structure, in this case either (LO) VC3 or (HO) STS-1 SPE.

It is very hard to imagine a network that supports the transport of a
mix of VC3 and STS-1. If it happens that due to the diverse routing
a number of VC3 have to travel through SONET land, they will have to
be converted to STS-1 SPE and back at the border. (STS-1 SPE travelling
through SDH world have to be converted to VC3).
The VCG is not aware of this, even if the VCG and the conversion
circuits are co-located in the same network element.

> I assume it is true that I can put multiple SDH VC11 or VC12 into a
> single VCG, and that some of those VC1x can be carried in HO VC3s and
> others in HO VC4s. So by analogy I think the above should be possible
> for VC3s.

Again as I stated above, a VCG is only concerned with members
that have the same structure (i.e. VC11, VC12, VC3 etc.) and
is NOT concerened with the way the members are transported in
the network.

Cheers, Huub.

-- 
                reply to hhelvooort with 2 'o's
================================================================
              http://members.chello.nl/hhelvoort/
================================================================
Always remember that you are unique...just like everyone else...

0
Reply Huub 11/4/2004 10:26:38 AM

Pieter Hulshoff <phulshof@xs4all.nl> wrote in message news:<418959c5$0$32076$e4fe514c@dreader18.news.xs4all.nl>...
> Kevin wrote:
> 
> >  is it possible to have a single VCG with multiple SDH VC3 members,
> > where some of those members are HO VC3 and some of those members are
> > LO VC3 (i.e., carried in a VC4-TUG3)? It seems that VCAT should only
> > be concerend with the fact that all members are VC3s and use the H4
> > multiframe.
> 
> Theoretically it should be doable, but what type of system should support
> this? In SONET you only have STS1-SPE (HO VC3), and in SDH only VC4-TU3-VC3
> (LO VC3). I could imagine starting out with LO VC3, and have part of your
> data routed through a SONET network after having been converted to HO VC3,
> but usually you'd convert back to one standard before handling LCAS. Of
> course there's the unlikely situation that your LCAS drop point is exactly
> at the border between two types of networks (one SONET, and one SDH), but
> even then I'd expect the data to be converted to one standard before
> dropping it.
> 
> Regards,
> 
> Pieter Hulshoff

Hi Pieter,
 by HO VC3 I meant AUG1-AU3-VC3 and by LO VC3 I meant
AUG1-AU4-VC4-TU3-VC3,
both in SDH, although the HO VC3 has a clear analog to SONET STS1. I
recognize that most (but not quite all) networks only support what I
defined as LO VC3. Maybe the answer here is that no network would ever
be doing both at the same time?

Thanks,
Kevin
0
Reply kfowler 11/4/2004 4:19:31 PM

Hi Kevin,

You wrote:

>  by HO VC3 I meant AUG1-AU3-VC3 and by LO VC3 I meant
> AUG1-AU4-VC4-TU3-VC3,
> both in SDH, although the HO VC3 has a clear analog to SONET STS1. I
> recognize that most (but not quite all) networks only support what I
> defined as LO VC3. Maybe the answer here is that no network would ever
> be doing both at the same time?

Both AU3 and TU3 mappings of VC3 are indeed mentioned in G.707,
however in the SDH world mostly the TU3 mapping is supported.
The SDH operators I have met do use this TU3 mapping (but I
may not have met them all  ;-)
The AU3 mapping is included only to show the SONET land mapping
for completeness.

Indeed there will not be a mix of TU3 and AU3 mappings, as this
would make the equipment expensive due to the required conversion
circuits. (One would find these only at the borders, as I mentioned
in my previous answer).

Cheers, Huub.

-- 
                reply to hhelvooort with 2 'o's
================================================================
              http://members.chello.nl/hhelvoort/
================================================================
Always remember that you are unique...just like everyone else...

0
Reply Huub 11/4/2004 5:02:50 PM

Kevin wrote:
>  by HO VC3 I meant AUG1-AU3-VC3 and by LO VC3 I meant
> AUG1-AU4-VC4-TU3-VC3,
> both in SDH, although the HO VC3 has a clear analog to SONET STS1. I
> recognize that most (but not quite all) networks only support what I
> defined as LO VC3. Maybe the answer here is that no network would ever
> be doing both at the same time?

AUG1 - AU3 - VC3 is a nice looking thing in the SDH standard, but it's just
a renaming of the STS1 - STS1-SPE SONET mapping. It's not really used in
SDH networks. As such your last statement is correct: one network would not
be doing both at the same time.

As said though: it _is_ possible that some VCs get routed through a SONET
network while others get routed through an SDH network. While being in the
SONET network, they'll be mapped as STS1 - STS1-SPE, and while being in the
SDH network, they'll be mapped as AU4 - VC4 - TU3 - VC3. This causes no
problems for VCAT. At the end of the network though, they're likely to be
in either SONET or SDH format.

Regards,

Pieter Hulshoff

0
Reply Pieter 11/4/2004 5:04:35 PM
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HO VC3 and "LO VC3" VCAT
Hi, is it possible to have a single VCG with multiple SDH VC3 members, where some of those members are HO VC3 and some of those members are LO VC3 (i.e., carried in a VC4-TUG3)? It seems that VCAT should only be concerend with the fact that all members are VC3s and use the H4 multiframe. I assume it is true that I can put multiple SDH VC11 or VC12 into a single VCG, and that some of those VC1x can be carried in HO VC3s and others in HO VC4s. So by analogy I think the above should be possible for VC3s. Thanks, Kevin Kevin wrote: > is it possible to have a single VCG with multiple SDH V...