User manual D-LINK DES-3208

[. . . ] DES-3208 10/100 Fast Ethernet Switch User's Guide Rev. 02 (January, 1998) 6DES3208. . 02 Printed In Taiwan RECYCLABLE Wichtige Sicherheitshinweise 1. Bitte lesen Sie sich diese Hinweise sorgfältig durch. Heben Sie diese Anleitung für den spätern Gebrauch auf. [. . . ] A very long Aging Time can result with the out-of-date Dynamic Entries that may cause incorrect packet filtering/forwarding decisions. In the opposite case, if the Aging Time is too short, many entries may be aged out soon, resulting in a high percentage of received packets whose source addresses cannot be found in the address table. Switch Management 27 10/100 Fast Ethernet Switch User's Guide Spanning Tree Algorithm The Spanning Tree Algorithm (STA) in the Switch allows you to create alternative paths (with multiple switches or other types of bridges) in your network. These backup paths are idle until the Switch determines that a problem has developed in the primary paths. When a primary path is lost, the Switch providing the alternative path will automatically go into service with no operator intervention. This automatic network reconfiguration provides maximum uptime to network users. The concept of the Spanning Tree Algorithm is a complicated and complex subject and must be fully researched and understood. Please read the following before making any changes . With STA, there will be only one path between any two LANs. If there is more than one path, forwarded packets will loop indefinitely. STA detects any looped path and selects the path with the lowest path cost as the active path, while blocking the other path and using it as the backup path. When the path for which there is a backup path fails, the backup path will be automatically activated, and STA will automatically re-configure the network topology. STA Operation Levels STA operates on two levels: the bridge level and the port level. On the bridge level, STA calculates the Bridge Identifier for each Switch, then sets the Root Bridge and the Designated Bridges. On the port level, STA sets the Root Port and Designated Ports. Details are as follows: 28 Switch Management 10/100 Fast Ethernet Switch User's Guide On the Bridge Level Root Bridge: The Switch with the lowest Bridge Identifier is the Root Bridge. Naturally, you will want the Root Bridge to be the best Switch among the Switches in the loop to ensure the highest network performance and reliability. Bridge Identifier: This is the combination of the Bridge Priority (a parameter that you can set) and the MAC address of the Switch. Example: 4 00 80 C8 00 01 00, where 4 is the Bridge Priority. A lower Bridge Identifier results in a higher priority for the Switch, and thus increases it probabily of being selected as the Root Bridge. Designated Bridge: From each LAN segment, the attached Bridge that has the lowest Root Path Cost to the Root Bridge is the Designated Bridge. It forwards data packets for that LAN segment. In cases where all Switches have the same Root Path Cost, the Switch with the lowest Bridge Identifier becomes the Designated Bridge. Root Path Cost: The Root Path Cost of a Switch is the sum of the Path Cost of the Root Port and the Root Path Costs of all the Switches that the packet goes through. [. . . ] Crossover cable for Switch (MDI-X port) to switch/hub or other network devices (MDI-X port) connection RJ-45 Pin Specification 73 10/100 Fast Ethernet Switch User's Guide C 9 MII CONNECTOR SPECIFICATIONS The MII (Media Independent Interface) is a 40 pin connector used for making connection with other LAN networks. This connector has a shared connection with port 2x, and when connected, the MII connection takes operational precedence over port 2x. The following Figure and table show the standard MII 40 pin connector and the pin assignment. Figure C-1. The Standard MII connector 74 MII Connector Specifications 10/100 Fast Ethernet Switch User's Guide MII Connector Pin Assignment Contact 1 2 MII Signal +5 V MDIO Signal Name Voltage MAC Data Input Output MAC Clock Data Contact 21 22 MII Signal +5 V --- Signal Name Voltage Ground 3 MDC 23 --- Ground 4 RXD<3> Receive Data 3 bit Receive Data 2 bit Receive Data 1 bit Receive Data 0 bit Receive Valid Data 24 --- Ground 5 RXD<2> 25 --- Ground 6 RXD<1> 26 --- Ground 7 RXD<0> 27 --- Ground 8 RX_DV 28 --- Ground 9 10 11 RX_CLK RX_ER NOT USED TX_CLK TX_EN Receive Clock Receive Error Not Used 29 30 31 ------- Ground Ground Ground 12 13 Transmit Clock Transmit Enable Transmit Data 0 bit Transmit Data 1 bit 32 33 ----- Ground Ground 14 TXD<0> 34 --- Ground 15 TXD<1> 35 --- Ground MII Connector Specifications 75 10/100 Fast Ethernet Switch User's Guide MII Connector Pin Assignment Contact 16 MII Signal TXD<2> Signal Name Transmit Data 2 bit Transmit Data 3 bit Collision Carry Sense Voltage Contact 36 MII Signal --- Signal Name Ground 17 TXD<3> 37 --- Ground 18 19 20 COL CRS +5 V 38 39 40 ----+5 V Ground Ground Voltage Table C-1. [. . . ]