Feb 24

Please Login the D-Link DGS-3612G Switch,default IP is 10.90.90.90.

The IP Address may initially be set using the console interface prior to connecting to it through the Ethernet. If the Switch IP address has not yet been changed, read the introduction of the DGS-3600 Series CLI Refence Guide or return to Section 4 of this manual for more information.

To view the Switch’s current IP settings, click Administration > IP Address, as shown below:

DGS-3612g

To manually assign the Switch’s IP address, subnet mask, and default gateway address:

1. Select Manual from the Get IP From drop-down menu.

2. Enter the appropriate IP Address and Subnet Mask.

3. If you will manage the Switch from the subnet on which it is installed, you can leave the default address (0.0.0.0) in this field.

4. If no VLANs have been previously configured on the Switch, you can use the default VLAN Name. The default VLAN contains all of the Switch ports as members. If VLANs have been previously configured on the Switch, you will need to enter the VLAN Name of the VLAN that contains the port connected to the management station that will access the Switch. The Switch will allow management access from stations with the same VID listed here.

NOTE: The Switch’s factory default IP address is 10.90.90.90 with a subnet mask of 255.0.0.0 and a default gateway of 0.0.0.0.

To use the BOOTP or DHCP protocols to assign the Switch an IP address, subnet mask, and default gateway address:
Use the Get IP From pull-down menu to choose from BOOTP or DHCP. This selects how the Switch will be assigned an IP address.

IP MTU Settings

The IP MTU Settings window is used to configure the IP layer MTU settings on the Switch. The MTU is the largest size of IP datagram which may be transferred using a specific data link connection. The MTU value is a design parameter of a LAN and is a mutually agreed value (i.e. both ends of a link agree to use the same specific value) for most WAN links. The size of MTU may vary greatly between different links. Instead of making routers fragment packets, an end system could try to find out the largest IP packet that may be sent to a specific destination.

When one IP host wants to transmit an IP datagram, it is usually preferable that the datagrams be of the largest size that does not require fragmentation anywhere along the path from the source to the destination. The path MTU is equal to the minimum MTUs of each hop in the path.

To configure the Switch’s current IP MTU settings, click Administration > IP MTU Settings, as shown below:

DGS-3612g-1

IP Interface Name:Specifies the name of the IP Interface to be used.

IP MTU (512-1712):The user can configure each interface’s IP MTU. If the user does not designate an MTU value when creating an interface, the default value of 1500 will be used.

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Aug 13

To find the proper MTU Size, you’ll have to do a special ping of the destination you’re trying to go to. A destination could be another computer, or a URL.

Step 1 Click on Start and then click Run.

Step 2 Windows NT, 2000, and XP users type in cmd and press Enter (or click OK).

Step 3 Once the window opens, you’ll need to do a special ping. Use the following syntax:

ping [url] [-f] [-l] [MTU value]

Example: ping yahoo.com -f -l 1472

dlink-mtu

You should start at 1472 and work your way down by 10 each time. Once you get a reply, go up by 2 until you get a fragmented packet. Take that value and add 28 to the value to account for the various TCP/IP headers. For example, lets say that 1452 was the proper value, the actual MTU size would be 1480, which is the optimum for the network we’re working with (1452+28=1480).

Once you find your MTU, you can now configure your router with the proper MTU size.

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Aug 13

A maximum transmission unit (MTU) is the largest size packet or frame, specified in octets (eight-bit bytes), that can be sent in a packet or frame-based network such as the Internet. The Internet´s Transmission Control Protocol uses the MTU to determine the maximum size of each packet in any transmission. Too large an MTU size may mean retransmissions if the packet encounters a router that can´t handle that large a packet. Too small an MTU size means relatively more header overhead and more acknowledgements that have to be sent and handled. Most computer operating systems provide a default MTU value that is suitable for most users. In general, Internet users should follow the advice of their Internet service provider (ISP) about whether to change the default value and what to change it to.

In Windows 95, the default MTU was 1500 octets (eight-bit bytes), partly because this is the Ethernet standard MTU. The Internet de facto standard MTU is 576, but ISPs often suggest using 1500. If you frequently access Web sites that encounter routers with an MTU size of 576, you may want to change to that size. (Apparently some users find that changing the setting to 576 improves performance and others do not find any improvement.) The minimum value that an MTU can be set to is 68.

For more recent Windows systems, the operating system is able to sense whether your connection should use 1500 or 576 and select the appropriate MTU for the connection.

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