Network Connections and Topologies 5

5.2.2 Star or Hub-and-Spoke networks

An alternative approach is to implement a network with Star topology, also referred to as ‘hub-and- spoke’ or ‘radial’ topology, using a number of Ethernet switches. (See figure 5.2.2.) In such a network, a group of PLMs (typically those inside the same rack) are connected directly to a switch also housed in the rack. These local switches are then connected to a “central” switch.

If dual redundancy mode is used, then a completely parallel secondary network can be created. The primary network would connect the primary port of each Dante equipped device (PLM or DLP) and the secondary network would connect all the secondary ports.

The dual redundancy mode has the benefit that any single switch can fail without causing an audible interruption in the network. However, the control and monitor PC will have to be manually switched between the primary and the secondary network if a failure on one network layer should occur.

A dual redundancy configuration doubles the number of switches and cables needed.

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.

802.11g/n

1000

1000

Rack

1000

100

100

100

1000

1000

Rack

1000

100

100

100

Rack

1000

100

100

100

Figure 5.2.2: Two level star topology

PLM Series Network Configuration Guide 9

Page 8 Page 10
Page 9
Image 9
3Com NCG-PLM, PLM Series manual Star or Hub-and-Spoke networks, Daisy-chained switches, Daisy-chained switch ring
Page 8 Page 10

NCG-PLM, PLM Series specifications

The 3Com NCG-PLM, PLM Series is a notable product line from 3Com Corporation designed to enhance network management and provide a robust infrastructure for businesses. This series is centered around providing seamless connectivity and efficient network performance while supporting a variety of applications and services.

One of the main features of the PLM Series is its advanced network management capabilities. The series offers a comprehensive suite of management tools that facilitate easy monitoring and configuration of network devices. This enables IT administrators to gain visibility into network performance, troubleshoot issues, and manage bandwidth effectively. The user-friendly interface simplifies these processes, allowing for quick adjustments and ensuring optimal functionality.

The PLM Series integrates cutting-edge technologies to support high-speed connectivity and data transfer. With support for Gigabit Ethernet, the series ensures that data can be transferred rapidly across networks, meeting the growing demands of modern applications and user expectations. Such speed is crucial for businesses that rely on data-intensive applications, video conferencing, and cloud services.

Furthermore, one of the hallmark characteristics of the 3Com NCG-PLM Series is its reliability and scalability. Designed to accommodate increasing network demands, the devices within this series can easily expand to support additional users and devices. This scalability ensures that organizations can grow without the need for extensive overhauls of their existing infrastructure.

Security is another paramount feature of the PLM Series. It employs various security protocols to protect sensitive data and maintain the integrity of the network. This includes measures against unauthorized access, ensuring that only authenticated devices and users can connect to the network. This commitment to security is critical in today’s climate where cyber threats are ever-evolving.

The PLM Series is also designed with energy efficiency in mind. The devices consume less power without compromising performance, thereby supporting sustainability initiatives within organizations. This energy-efficient design can result in significant cost savings on power consumption over time.

In summary, the 3Com NCG-PLM, PLM Series stands out for its advanced network management tools, high-speed connectivity, reliability, scalability, strong security measures, and energy efficiency. These attributes make it an ideal choice for businesses seeking to optimize their network infrastructure and cope with the increasing demands of modern digital operations.
Top Page Image Contents