ReDop Networks

 Redundancy-optimized networks with savings potential

System stability with ReDop networks

System stability is one of the most important prerequisites for high-performance data center architectures. In order to guarantee uptimes of more than 99,99 % it is paramount to implement redundancy for important system areas also in spine-leaf architectures. Currently, this is realized in the Main Distribution Area (MDA) by doubling transceivers and signal paths. This doubling, however, puts additional load on the heavily used mesh layer. 

CrossCon Redundanz

Example: 2x2 Spine-Leaf-Architecture

The figure on the right shows a classical redundant architecture. There are two signal paths from each switch to the correlating switches. In case line 1 between L1 and S1 fails, the data transmission is ensured via line 2. Currently, this type of redundant signal paths is considered the standard in data center architecture. However, it implies avoidable inefficiency in signal paths and transceivers. 

ReDop ohne CrossCon

Redundancy-optimized networks (ReDop) developed by FiberCon constitute a considerable MDA optimization in 40/100G networks. Savings potential of at least 25% can, thus, be realized.
Lines 1 to 6 symbolize 8-channel trunk cables. Using the transceiver split mode, 4 channels of every cable are assigned to S1 and 4 channels to S2. In the case of a QSFP28 that means 50G data transmission to each of the two spines. Hence, lines 1 and 2 are required in order to realize 100G. 

ReDop mit CrossCon

In case of failure of one of these signal paths, it is replaced by line 3. This guarantees lossless signal transmission. The same signal distribution is applied for L2.

The CrossCon® as central component of the ReDop network assigns the signals of both leafs to the according switches, so that lines 4, 5 and 6 contain 4 channels of L1 and 4 channels of L2, respectively.

This reduction in signal paths also means a reduction in transceivers as shown in this example with 2 transceivers per signal path. It must be noted that ReDop networks are scalable in accordance with growing switch numbers as can be seen in the table below. The channel number of the QSFP transceivers used causes the current limitation in savings potential of 37,5 %. Transceivers with higher channel numbers may increase the savings potential up to 50%.  

n (Spines) M (Leafs) QSFP (old) QSFP (new) Reduction
2432248 (25 %)
26483612 (25 %)
36724824 (33,3 %)
46966036 (37,5 %)
810320200120 (37,5 %)
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