R&M Data Center Handbook

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Method R
Method R (a designation defined by R&M) has been available since 2011. It requires just one type of patch cord
(A-to-B). The crossover of the fibers for duplex signal transmission (10 GBase-SR) takes place in the preassembled
cassette. The connectivity diagram for the trunk cable and patch cord or the light guidance remains the
same all the time, even for parallel transmission (Method B) for setting up 40/100 GbE installations. That means
capacity can be expanded directly in an uncomplicated and inexpensive manner. In addition, the only thing that
has to be done is replace the cassettes with panels.
The table below summarizes the described methods once again:
Polarity
method
MPO/MTP
Cable
MPO module
Duplex patch
cable
TIA-568.C
Standard
(duplex signals)
A
B
C
Type A
Type B
Type C
Type A
(Type A Adapter)
Type B1, Type B2
(Type B Adapter)
Type A
(Type A Adapter)
1 x A-to-B
1 x A-to A
2 x A-to-B
2 x A-to-B
R
Type B
Type R
(Type B Adapter)
2 x A-to-B
TIA-568.C
Standard
(parallel signals)
Polarity
method
MPO/MTP
Cable
A Type A Type A
Adapter plate
MPO/MTP
Cable
1 x Type A
1 x Type B
B Type B Type B 2 x Type B
Polarity, methods and component types
Type A: MPO/MTP Cable
Key-up to key-down
Type B: MPO/MTP Cable
key-up to key-up
Type C: MPO/MTP Cable
Key-up to key-down, flipped pair-wise
Fibers
1
2
3
4
5
6
7
8
9
10
11
12
Key-Up
Key-down
Pos. 1
Pos. 1
Pos. 12 Pos. 12
Fibers
1
2
3
4
5
6
7
8
9
10
11
12
Fibers
1
2
3
4
5
6
7
8
9
10
11
12
Key-Up
Key-down
Pos. 1
Key-up
Key-down
Pos. 12
Pos. 12 Pos. 1
Fibers
1
2
3
4
5
6
7
8
9
10
11
12
Fibers
1
2
3
4
5
6
7
8
9
10
11
12
Key-Up
Key-down
Pos. 1
Pos. 1
Pos. 12 Pos. 12
Fibers
2
1
4
3
6
5
8
7
10
9
12
11
Duplex patch cable A-to-B
Type A Adapter
Key-up to key-down
Type B Adapter
Key-up to key-up
Duplex patch cable A-to-A
The complete rebuilding of a data center is certainly not an everyday event. When it is done, the operator has the
option of relying immediately on the newest technologies and to lay the groundwork for higher bandwidths.
Gradually converting or expanding existing infrastructure to accommodate 100 Gb/s will be a common occurrence
in the years ahead, indeed it will have to be. A useful approach involves successively replacing first existing
passive components, then active components as they become available and reasonably affordable. The capacity
expansion is usually done in three steps:
Page 132 of 156 © 08/2011 Reichle & De-Massari AG R&M Data Center Handbook V2.0