Understanding KLM nomenclature in SDH & SONET

The format of the label for SDH and/or SONET TDM-LSR link is:
https://docs.google.com/file/d/0BwE3NGerAe3tbXZ0NHhfUHpQbkk/edit?usp=sharing
0                    1                    2                    3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
|               S            |   U    |   K    |   L      |   M      |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
For SDH, this is an extension of the numbering scheme defined in
G.707 section 7.3, i.e. the (K, L, M) numbering. For SONET, the same
signaling scheme is used in order to provide easy interworking between
SDH and SONET signaling. For the S field a STS-3 group, which
corresponds with the SDH AUG-1 level is introduce. The U field indicates
the position of the STS-3c-SPE or STS-1-SPE within the STS-3 group

1. S is the index of a particular AUG-1/STS-3 group. S=1->N
indicates a specific AUG-1/STS-3 group inside an STM-N/STS-3xN
multiplex. For example, S=1 indicates the first AUG-1/STS-3 group,
and S=N indicates the last AUG-1/STS-3 group of this multiplex.
S is not significant for STM-0/STS-1.

2. U indicates a specific VC/STS-SPE inside a given AUG-1/STS-3
group or STM-0/STS-1. U=1 indicates a single VC-4/STS-3c-SPE in a
AUG-1/STS-3 group or the single VC-3/STS-1-SPE in a STM-0/STS-1, while U=2->4
indicates a specific VC-3/STS-1-SPE inside the given AUG-1/STS-3
group.

3. K is only significant for VC-4/STS-3c and must be ignored for
higher order VC-3/STS-1-SPE. For SDH it indicates a specific branch of a VC-4.
K=1 indicates that the VC-4 is not further subdivided and
contains a C-4. K=2->4 indicates a specific TUG-3 inside the VC-4.
For a SONET STS-3c-SPE it is fixed to K=1 as SONET doesn’t support
substructured STS-3c-SPE.

4. L indicates a specific branch of a TUG-3, VC-3 or STS-1 SPE.
It is not significant for an unstructured VC-4/STS-3c-SPE. L=1
indicates that the TUG-3/VC-3/STS-1 SPE is not further
subdivided and contains a VC-3/C-3 in SDH or the equivalent in
SONET. L=2->8 indicates a specific TUG-2/VT Group inside the
corresponding higher order signal.

5. M indicates a specific branch of a TUG-2/VT Group. It is not
significant for an unstructured VC-4, STS-3c-SPE, TUG-3, VC-3 or STS-1 SPE.
M=1 indicates that the TUG-2/VT Group is not further subdivided
and contains a VC-2/VT-6 SPE. M=2->3 indicates a specific VT-3
inside the corresponding VT Group, these values MUST NOT be used
for SDH since there is no equivalent of VT-3 with SDH. M=4->6
indicates a specific VC-12/VT-2 SPE inside the corresponding
TUG-2/VT Group. M=7->10 indicates a specific VC-11/VT-1.5 SPE
inside the corresponding TUG-2/VT Group. Note that M=0 denotes
an unstructured VC-4, VC-3 or STS-1 SPE (easy for debugging).