EDS-408A/405A Series User’s Manual

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STP Example

The LAN shown below has three segments, with adjacent segments connected using two possible links. The various STP factors, such as Cost, Root Port, Designated Bridge Port, and Blocked Port are shown in the figure.

LAN Segment 1

Port 1 (Designated Bridge Port)

Bridge A

Port 2

(Root Bridge)

Port 1

(Root Port)

Cost =100

Bridge B

Port 2 (Designated Bridge Port)

Port 1

(Root Port)

Cost =100

Bridge X

Port 2 (Blocked Port)

LAN Segment 2

Port 1

(Root Port)

Cost =100

Bridge C

Port 2 (Designated Bridge Port)

Port 1

(Root Port)

Cost =200

Bridge Y

Port 2 (Blocked Port)

LAN Segment 3

yBridge A has been selected as the Root Bridge, since it was determined to have the lowest Bridge Identifier on the network.

ySince Bridge A is the Root Bridge, it is also the Designated Bridge for LAN segment 1. Port 1 on Bridge A is selected as the Designated Bridge Port for LAN Segment 1.

yPorts 1 of Bridges B, C, X, and Y are all Root Ports since they are nearest to the Root Bridge, and therefore have the most efficient path.

yBridges B and X offer the same Root Path Cost for LAN segment 2. However, Bridge B was selected as the Designated Bridge for that segment since it has a lower Bridge Identifier. Port 2 on Bridge B is selected as the Designated Bridge Port for LAN Segment 2.

yBridge C is the Designated Bridge for LAN segment 3, because it has the lowest Root Path Cost for LAN Segment 3:

¾The route through Bridges C and B costs 200 (C to B=100, B to A=100)

¾The route through Bridges Y and B costs 300 (Y to B=200, B to A=100)

yThe Designated Bridge Port for LAN Segment 3 is Port 2 on Bridge C.

Using STP on a Network with Multiple VLANs

IEEE Std 802.1D, 1998 Edition, does not take into account VLANs when calculating STP information—the calculations depend only on the physical connections. Consequently, some network configurations will result in VLANs being subdivided into a number of isolated sections by the STP system. You must ensure that every VLAN configuration on your network takes into account the expected STP topology and alternative topologies that may result from link failures. The following figure shows an example of a network that contains VLANs 1 and 2. The VLANs are connected using the 802.1Q-tagged link between Switch B and Switch C. By default, this link

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Moxa Technologies EDS-408A, 405A SERIES user manual STP Example, Using STP on a Network with Multiple VLANs
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405A SERIES, EDS-408A specifications

Moxa Technologies has established itself as a leader in networking solutions, particularly for industrial applications. Among their cutting-edge products is the 405A Series, specifically the EDS-408A model, which exemplifies Moxa's commitment to performance, reliability, and versatility in industrial Ethernet switches.

The EDS-408A is an 8-port industrial Ethernet switch that offers an impressive array of features and capabilities designed to meet the demands of harsh environments. One of its main highlights is the ability to support both 10/100 Mbps Fast Ethernet and Gigabit Ethernet connections, providing users with the flexibility to integrate a range of devices within their network. Its robust design ensures that it operates seamlessly in extreme conditions, with a wide operating temperature range from -40 to 75 degrees Celsius.

The EDS-408A is built to support an array of networking topologies. It features advanced Ethernet switching technologies that enable fast and efficient data transfer while minimizing latency. The device is equipped with wire-speed forwarding capabilities, which is vital for maintaining high performance in heavy network traffic scenarios.

Another key feature of the EDS-408A is its redundancy support. The switch incorporates various redundancy protocols, including Rapid Spanning Tree Protocol (RSTP) and MRP (Media Redundancy Protocol), which enhance network reliability by allowing quick recovery in the event of a failure. This ensures continuous network uptime, which is critical for industrial applications.

Furthermore, Moxa Technologies has adopted an user-friendly web-based management interface in the EDS-408A, simplifying the configuration and monitoring process. This allows system administrators to easily manage settings, monitor traffic, and troubleshoot issues in real time. Additionally, the switch supports SNMP (Simple Network Management Protocol) for remote monitoring and management, enabling organizations to keep their networks optimized.

Security is another paramount feature of the EDS-408A. It includes built-in security mechanisms such as port security, VLAN, and access control lists (ACLs), which help safeguard sensitive network segments from unauthorized access.

In conclusion, Moxa Technologies' EDS-408A model from the 405A Series is a robust and feature-rich industrial Ethernet switch designed for demanding environments. With its support for various network protocols, redundancy features, user-friendly management, and enhanced security, the EDS-408A stands out as a reliable solution for organizations looking to enhance their industrial networking capabilities.
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