Subject: Re: SONET MIB using for the SDH

From: [email-masked]
Date: Thu, 25 Feb 1999 12:19:57 +0200

On Sun, 21 Feb 1999 19:09:07 C. M. Heard/VVNET,Inc wrote:

>In the SONET-MIB the AU4 (STS-3c) and the VC4 (STS-3c SPE) are represented
>by the *same* ifTable conceptual row.  That is done because these elements
>stand in one-to-one correspondence (there is one and only one VC-4
>associated with a given AU4 and vice-versa), and there is little to be
>gained by having a separate conceptual row for each.  Faults for both
>are recorded by the sonetPathCurrentStatus object, which has bits to
>represent LOP and AIS defects (which are associated with the AU4) as well
>as Unequipped and Path Signal Label Mismatch defects (which are associated
>with the VC4).

>Likewise, the TU12 (VT-2) and the VC12 (VT-2 SPE) stand in one-to-one
>correspondence;  thus, both elements are represented by a common ifTable
>conceptual row, and defects for both elements are represented by bits in
>the sonetVTCurrentStatus object.

SDH has cross-connection function between VC12 and TU12. VC and TU one-to
one correspondence is correct if we don't need to use it.
For example, if we need protection then two TU12 correspond to single VC12.
First TU12 is working and connected to VC12. Second TU12 is allocated for
the same VC12 and not in use. But anyway the second TU12 should be ready to
work, so we need to monitor it by manager.

How can we use SONET-MIB to manage situation like this? It can be done more
simple if TU12 and VC12 are different objects.

All this correct for other VCs.

Thanks,

Radion Mirchevsky,

Network Management Group,
Network Systems Department
ECI Telecom Ltd.
e-mail : [email-masked]

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From: "C. M. Heard/VVNET, Inc." <[email-masked]>
Date: Fri, 26 Feb 1999 08:47:10 -0800 (PST)

> simple if TU12 and VC12 are different objects.

One suggestion that comes to mind is to model the "spare" TU12s via separate
ifTable entries of ifType = 51(sonetVT), and instantiate the corresponding
SONET-MIB sonetVT managed objects, but do NOT indicate (via the ifStackTable)
that these "spares" are connected to any lower layer while they are not in
use.  You will then need to add objects to your enterprise MIB to indicate
which of the active ifTable entried of ifType = 51(sonetVT) that the "spare"
object is backing up, and to manage the switchover.

Mike
-- 
C. M. Heard/VVNET, Inc.
[email-masked]