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Also note that the Dolby Lake Processor (DLP) does not support this redundancy scheme via dual rear panel Ethernet connectors, so one DLP per network layer would be required. 5.2.3 Daisy-chained switches In such a topology, each group of PLM Series units (typically those inside the same rack) have a switch inside the rack to which each has a direct connection. These “local” switches are connected in a daisy chain (figure 5.2.3). Systems of this type can be made quite large if the switches are using 1000BASE-T (Gigabit Ethernet), and although this is a very convenient system when it comes to wiring, a topology of this type can potentially develop SPF issues. 5.2.4 Daisy-chained switch ring This is an enhanced variant of the above that can be created if the switches support RSTP, or Rapid Spanning Tree Protocol. (See section 7, References and Definitions, for more information.) The benefit of this configuration is that, if there is a cable failure, the network will recover; all devices on the network (PLMs, switches, routers, etc.) will still be able to communicate. If a switch fails, all devices will remain connected to the network, with the exception of those devices that are directly connected to the failed switch. If Dante is being used, there will be a brief audible interruption in the sound (5 ms – 2 s), the length of which will depend on the size of the system and the vendor of the switch. The PLM’s own internal switches do not support RSTP. Care must be taken to not create a ring (closed loop) with the PLM’s rear panel connectors. 10001000Rack100010001000802.11g/n100100100Rack1000100100100Rack1000100100100Figure 5.2.2: Two level star topology PLM Series Network Configuration Guide 9 5 NeTwORk CONNeCTIONS aND TOPOLOgIeS 5 NeTwORk CONNeCTIONS aND TOPOLOgIeS 1000Rack1000100010001001001001000Rack10001001001001000Rack10001001001001000 Figure 5.2.3: Daisy chained switches Rack100010001000100100010010001001000100100100100010010010001000Rack10001000100100100100010010010001000Rack10001001001001000100 1001000 Figure 5.2.5: Dual daisy chain switch topology 5.2.5 Dual daisy-chained switches This is a hybrid that combines the ease of wiring of the daisy chain topology with the 100% avoidance of SPF issues in the dual redundant star/spoke configuration (figure 5.2.5). It is simply two “daisy chained switch” networks in parallel: the primary and secondary networks are connected independently using the dual redundant mode in the PLMs. If the control computer only has one network card, it can be connected to only one of the network layers. The solution to this situation can be as follows: • Manually disconnect from the “blue“ network layer and connect to the “red” network layer instead if one or more PLMs are inaccessible via the blue network (see figure 5.2.5). This can be done easily by using a simple hardware switch box. • A more advanced solution would be to equip the PC with two identical network cards and appropriate drivers so that it can be connected to both networks simultaneously. may be to place a group of local switches in each “zone”, which are first interconnected to form a “local area network” (e.g. Stage Left). These area networks are then interconnected with a main backbone. A different topology for the main backbone than that of the local area network may be chosen, depending on your specific application and resources. Figure 5.2.6 shows an example of a combined network utilizing both Star and Daisy Chained switch ring topologies. 5.3 Ethernet Cabling Limitations The maximum cable length allowed between any two devices on a network is defined by the Ethernet protocol and is limited to 100 meters (330 feet) for copper connections. The term “devices” includes: • The host PC running the Dolby Lake Controller PLM Edition software • Any switch on the network • Any access point • Any PLM Optical fiber can be used if longer distances are 5.2.6 Other combination networks needed. Multi-mode fiber supports up to 550 meters In larger system network topologies, a good solution (1800 feet) and single mode supports even longer 10 PLM Series Network Configuration Guide NeTwORk CONNeCTIONS aND TOPOLOgIeS 5 NeTwORk CONNeCTIONS aND TOPOLOgIeS 5 Rack 1000 1000 100 100 100 1000 Rack 1000 100 100 100 1000 1000 Stage Right 1000 Rack 1000 100 100 100 1000 Rack 1000 100 100 100 1000 1000 Stage Left FoH 1000 1000 1000 1000 Figure 5.2.6: Combined network topology distances. The recommended LinkSys switch can be upgraded with SFP modules to support fiber connections (See section 7, References and Definitions, for more information on SFP.) System type Source Backbone Sink Link speed [Mbps] 1* 2** 100 100 100 1000 100 100 Network diameter [# of “hops”] Latency setting 1 Latency setting 1 Latency setting 2 ms ms ms 14 62 1 4 1 1 2 9 4 19 14 >20 56 256 9 45 7 34 0.8 1.3 4.0 * PLM/DLP without external switches or with 100 Mbps switches (not a recommended setup!) ** Recommended PLM only example with Gigabit switch backbone Table 5.4...

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