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In the first group of switches, no configurations can be made. This is also not necessary for the general operation of a switch.

The second group of switches can be configured via a web server, for example. Such an approach is of interest for the diagnosis of the network.

The above Figure shows the industrial switch FL SWITCH SFN 8GT Gigabit Switch from Phoenix Contact. Some typical technical features of such switches are:

SMCS stands for Smart Managed Compact Switch. This switch corresponds to the IEEE802.3 standard and used for building automation networks based on Ethernet. He has eight RJ45 ports for connecting twisted pair cables. All ports support 10/100/1000 Mbit / s as well as auto-negotiation and auto crossing.

The switch is suitable not only for use as a standard Ethernet switch, especially for applications in the field Profinet RT and Ethernet / IP and supports necessary for this management function. Furthermore, the switch IGMP Snooping for Ethernet / IP.

Redundant network structures can the (Rapid) Spanning Tree Protocol or the Media Redundancy Protocol be constructed in accordance with. This ensures optimum operation of the network is guaranteed regardless of the comparable used topology.

Within complete network systems, information may be retrieved from the switch via SNMP. Configuration and diagnostics are possible via web server, SNMP, Telnet, or a V.24 interface (RS232).

The FL SWITCH SMCS 8GT is a store-and-forward switch. All data messages that reach the switch on a port are initially stored in a buffer and checked for validity. Corrupt data packets, i.e., those having a size of more than 1,522, or less than 64 bytes or packets with a checksum error occurs, must be discarded. Valid data packets are then forwarded via the correct port immediately. The transmission speed is set for each port through the connected network segment.

The switch dynamically learns all the addresses of the various network devices by extracting each incoming message, the source address. It can store up to 8000 addresses save in the address table. The aging time is 40 seconds (default) and is comparable changed. This time can be set via SNMP or Web-based management to a value between 10 and 825th . All addresses that were no longer needed after this time will be automatically deleted from the MAC address table.

The switch has a signaling contact. This signaling contact is closed floating and when properly function of the switch. With its help, the function of the switches is monitored. It is opened under the limited circumstances described below. At the restart, the switch performs a hardware self-test. If an error is detected, the alarm contact is opened. During normal operation, a watchdog device monitors the cyclical execution of the software program. If this watchdog body fails triggered cyclically by the software, the signaling contact is opened.

The user is optimized with the help of various status LEDs on the status of the switch informed. In this way, a local diagnosis without the use of additional tools is possible.

The SMCS switch supports autocrossing. Thus, it is not necessary more to distinguish between crossed and uncrossed twisted-pair Ethernet cables.

The SMCS switch supports auto-negotiation. In this case, the switch detects the parameters from a certain subnet on each port and configures the respective RJ45 port accordingly. The detected parameters are transmission speed (10, 100, or 1000 Mbit / s) and transmission mode (half or full-duplex). This automatic detection makes manual intervention by the user superfluous. The auto-negotiation function can be activated via the web-based management on or off.

(Are so if RD + and RD- reversed) with the use of twisted-pair cables with the wrong polarity, the switch reverses the polarity to automatically internally. This property is known as Auto Polarity Exchange.

The switch checks at predetermined times networks that are connected to each port sub. He uses link test signals as described in IEEE 802.3, to the connected TP / TX cable to check for short circuit and interruption.

The switch can receive in two different ways an IP address either via the BootP protocol or the serial V.24 interface. The factory, the assignment of the IP address on BootP, is set. There is a configuration software available to one to assign the IP address, if necessary, the switch easily. The mechanisms mechanism for assigning an IP address can be set interface via the Web-based management or V.24.

The switch in Smart Mode can be set using the MODE button on the front of the module. In Smart mode, the switch may be in a different mode shifted advertising to without using the management interfaces. In addition, the Smart mode, the factory settings can be restored.

The switch can be configured as a Profinet-IO device on the Web-based manage- or smart mode between operating modes Default (standard Ethernet switch) and Profinet IO or Ethernet / IP can be selected. If the switch is configured as a Profinet IO device, he can be recorded as such in the Profinet engineering software. In this way, a byte of diagnostic information that is provided in the engineering software for each input of the switch.

The SMCS switch supports the LLDP protocol, according to IEEE802.1AB. The switch sends and receives management and connection information to/from adjacent (n) devices (s). Thus visually displayed on available tools network architectures and monitors advertising to. The Profinet engineering software uses this information to a network diagnosis visually represent.

The switch, according to different priorities, queues two different (traffic classes according to IEEE802.1D). Received data packets are assigned to one of these queues according to their priority. The priority is given in the VLAN tag of the Ethernet frames. So that the transmission of high-priority data is not hindered by large amounts of data with low priority is avoided. In the event of an overload, data is no longer assumed to be a low priority. This principle is applied, among others, Profinet RT and is their quality of service.

The switch can handle a VLAN tag according to IEEE 802.1Q. This day consists of four bytes and is in the Ethernet frame between the source address and type field. Three bits of the four bytes represent the priority. About the Web-Based Management, different VLANs per port can be set on the switch. In this way, different VLANs can structure within a network with such switches build. Within a physical network, so different logical networks can be created.

The switch supports Spanning Tree Protocol (STP) and Rapid Spanning Tree Protocol (RSTP). STP is described in IEEE802.1d and allows the formation of a ring or mesh structures in the topology of a network made through the mesh structure kön- enables multiple communication paths between two devices. To prevent infinite loops and broadcast flooding, the switch cuts off some of the compounds. In the case of a cable break, the network after a specified time (20 to 50 s), the conjunction of switching on the switched-off ports restores. Powered-off ports can still receive data, but not send more. All active ports send data.

RSTP is a newer version of the STP and enabling switching times of 1 to 10 seconds. Also, the RSTP support ring and mesh structures. In the RSTP configuration, RSTP Fast Ring Detection can be activated.

The SMCS supports the Media Redundancy Protocol (MRP). This will pour into a Ring topology after an error occurs, a recovery time of a maximum of 200 ms allows.

Via SNMP (Simple Network Management Protocol), the device can be monitored via the network. An SNMP management system provides the ability to read the device configuration data to diagnose and change it. It supports SNMP versions 1 and 2c. The following MIBs are supported: RFC1213, RMON MIB, Bridge MIB, If-MIB, Ether like MIB, Iana-Address-Family-MIB, IANA if Type MIB, P-Bridge-MIB, Q-Bridge MIB, SNMPv2 MIB, SNMP-FRAMEWORK-MIB, and its own SNMP objects from Phoenix Contact (FL-SWITCH-M-MIB).

A serial connection to the switch can be provided via a V.24 interface (RS232) manufacturing. The cable is connected to the COM port of the PC and the switch to a mini-DIN connector. In this connection, the serial communication is done via a program such as HyperTerminal. This interface IP address, subnetworks, and default gateway are set. The address for the automatic assignment of an IP used BootP can be turned on or off. The parameters can be through this interface to store, and it can restart the unit carried out by the advertising. Also, resetting the device to factory settings is possible.

Another interface provides management Web-based. This interface provides diagnostic and configuration capabilities at startup and during operation of the device, and if errors occur. And network and device information on the web-based management can be polled. With the web-based management can be (namely on the basis of a web browser) to query a general hand-known, all information from the device.

Technical data, installation data, local diagnostic information can be queried. Furthermore, all configuration parameters (IP configuration, SNMP configuration, software updates, and passwords) can be checked and can be changed under the item Switch station "various diagnostic information about the various ports and the signal contacts are monitored.

Each port can be individually enabled or disabled. For each port, all transmission parameters can be adjusted, and web-based management, static information can be queried about the data itself. Also, the Port Mirroring "can be activated. With this function, it is possible, all the data are sent via a specific port or received to also send to a different port. This is important for error detection using a network sniffer.