Case

1.1     General Description

eWAVE4107DiR supports 2 types of Ring application: Active Ring and Passive Ring. Active Ring means every pass through channel in one node have an O-E-O conversion. This type of Ring application is often used in CWDM system, because O-E-O conversion is relative cheaper in CWDM system. Another reason is that EDFA can not be used in CWDM system, so when in long haul application (totally more than 100km in ring), customer have to use Active Ring. Passive Ring doesn’t have O-E-O conversion of pass through channel. By customer specified OAD module, some pre-defined channels can be add to and drop from ring. Compare to Active Ring, this is a cost effective solution. But there is a limitation that total length can not beyond 100km in the ring for CWDM. In the case of DWDM, because customer can use EDFA and DCF to expand transmission distance, so there is no 100km limitation. EDFA and DCF should be carefully designed according to different applications.

The usage of Active Ring is very simple. For each node, two eWAVE4107DiR are configured back to back. One is for east port; the other is for west port. Client ports can be connect directly between two eWAVE4107DiR for pass through channels. Client ports of Add and Drop channels are connected to customer equipment, such as router, switch. Figure 2 shows the configuration of one node of Active Ring. Figure 3 shows the application of Active Ring. At each node, low speed traffic from FE, OC3/OC12, FC, ESCOM/FICON, DTV, 1 GE, OC2.5, and high speed 10 GE and OC192 can be add/drop are any nodes .

1.1    Passive Ring

To eliminate the O-E-O conversion, eWAVE4107DiR can support Passive Ring application by using OAD module. OAD module is customer specified according to different application. Block diagram of Passive Ring node is shown in figure 4.

Figure 4: block diagram of Passive Ring Node

 Pass through wavelengths, add and drop wavelength are pre-defined in the design of OAD module. There are many kinds of OAD module with different structure. Specifications, such as insertion loss, are also different..

Passive Ring can be used in both CWDM and DWDM system. For no EDFA application, as CWDM system, total length of the ring can not beyond 100 km. Figure 5 and figure 6 show typical applications of Passive Ring.

*For CWDM application, total length should not beyond 100km

Figure 5: Typical application 1 of Passive Ring

Application 1 is often used for metro aggregation transport networking; traffic from Node A, Node B and Node C are aggregated to HUB node.

*For CWDM application, total length should not beyond 100km

Figure 6: Typical application 2 of Passive Ring

Application 2 is often used in metro core transport network, which traffic of every node is always balanced. Both of these two applications are support optical layer protection.