Question about Siemens SpeedStream Modem (4100) (SS4100)

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M t u

What the **** is mtu

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In computer networking, the term Maximum Transmission Unit (MTU) refers to the size (in bytes) of the largest packet that a given layer of a communications protocol can pass onwards.
MTU parameters usually appear in association with a communications interface (NIC, serial port, etc.).
The MTU may be fixed by standards (as is the case with Ethernet) or decided at connect time (as is usually the case with point-to-point serial links).
A higher MTU brings higher bandwidth efficiency. However, large packets can block a slow interface for some time, increasing the lag on other packets. For example, a 1,500-byte packet, the largest allowed by Ethernet (and most of the Internet), would block up a 14.4k modem for about one second.
The default MTU on a PPPoE connection is 1,492. The default MTU for a DHCP or PPPoA connection is 1,500.
Increasing the MTU size beyond these levels is possible on a client computer, but not recommended, because the MTU size on the outbound connection to the ISP will nullify any potential gains from a larger MTU.

Posted on Apr 21, 2008

  • Van Estella
    Van Estella Apr 21, 2008

    Finding the Correct MTU
    To find the correct MTU for your configuration you must run a simple
    DOS Ping test. You will simply send out ping requests and progressively
    lower your packet size until the packet no longer needs to be
    fragmented. Please reference the following steps:

    The command for this ping test is ping www.urlname.com -f -l xxxx.
    You can use any well known, pingable domain like ping www.google.com -f -l xxxx in place of www.urlname.com for the test.
    •There is a single space between each command.
    •"-l" is a lower case letter L, not the number one.
    •The xxxx are the test packet size. (like 1472)
    At the DOS Prompt type in ping www.google.com -f -l 1472 and hit Enter. Notice that the packet needs to be fragmented. (you get a message "packet needs to be fragmented but DF set")
    Drop the test packet size down (10 or 12 bytes) and test again. If the packet still needs to be fragmented, drop the test packet size down more and test again until your reach a packet size that does not fragment.Once you have a test packet that is not fragmented increase your packet
    size in small increments and retest until you find the largest possible
    packet that doesn't fragment. Take the maximum packet size from the ping test and add 28. You add 28 bytes because 20 bytes are reserved for the IP header and 8 bytes must be allocated for the ICMP Echo Request header. Remember: You must add 28 to your results from the ping test!
    An example:
    1440 Max packet size from Ping Test
    + 28 IP and ICMP headers
    1468 your optimum MTU setting

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Posted on Jan 02, 2017

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1 Answer

How do i change my mtu settinggs


To change the MTU rate on your router follow the steps below:
Open your browser, enter the IP address of your router (192.168.0.1) and click OK.
Enter your username (admin) and password (blank by default).
Click OK to enter the web configuration page for the device.
Click on Setup and then click Manual Configure.
To change the MTU enter the number in the MTU field and click Save Settings.
If changing the MTU does not resolve the problem, continue changing the MTU in increments of ten.

1500 is the default MTU for Dynamic (DHCP) Cable (p. 20 in user manual).
1492 is the default MTU for PPPoE (Point to Point Protocol over Ethernet) DSL (p. 22 in user manual).
Other MTU settings are listed in the manual, simply do a search for "MTU".

Note: AOL DSL+ users must use MTU of 1400.

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 (p. 86 in user manual).

Here is the PDF link to the User Manual:
http://www.dlink.com/-/media/Consumer_Products/DGL/DGL%204500/Manual/DGL%204500_Manual_EN_US.pdf

Sep 20, 2011 | D-Link DGL-4500 Wireless Router

Tip

Increasing Speed of Internet Using MTU settings in xp


Increasing Speed of Internet Using mtu settings in Windows XP:
Maximum Transmission Unit (MTU) refers to the size (in bytes) of the largest packet that a given layer of a communications protocol can pass onwards. MTU parameters usually appear in association with a communications interface. The MTU may be fixed by standards (as is the case with Ethernet) or decided at connect time (as is usually the case with point-to-point serial links). A higher MTU brings higher bandwidth efficiency.

Maximum Transmission Unit (MTU) refers to the size (in bytes) of the largest packet that a given layer of a communications protocol can pass onwards. MTU parameters usually appear in association with a communications interface. The MTU may be fixed by standards (as is the case with Ethernet) or decided at connect time (as is usually the case with point-to-point serial links). A higher MTU brings higher bandwidth efficiency.

The default and maximum PPPoE MTU size is 1,480 bytes. With some Internet service providers (ISPs), you may have to reduce the MTU size of a PPPoE connection to a value between 1,400 and 1,480 (for example, to 1,454). Do not set an MTU size smaller than 1,400.
Modify the MTU size requires registry editing in windows xp
WARNING: If you use Registry Editor incorrectly, you may cause serious problems that may require you to reinstall your operating system. Microsoft cannot guarantee that you can solve problems that result from using Registry Editor incorrectly. Use Registry Editor at your own risk.
To modify the PPPoE MTU size, create the following registry key:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Ndiswan\Parameters\Protocols\0
Then add the following registry entries.Entry name Data type Value data
ProtocolType REG_DWORD 0x00000800
PPPProtocolType REG_DWORD 0x00000021
ProtocolMTU REG_DWORD the appropriate MTU size (in decimal)

1. Click Start, click Run, type regedit, and then click OK.
2. Locate and then click the following key in the registry:
HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\Ndiswan\Parameters
3. On the Edit menu, point to New, and then click Key.
4. Type Protocols, and then press ENTER.
5. On the Edit menu, point to New, and then click Key.
6. Type 0, and then press ENTER.
7. On the Edit menu, point to New, and then click DWORD Value.
8. Type ProtocolType, and then press ENTER.
9. On the Edit menu, click Modify.
10. Type 800, and then click OK.

11. On the Edit menu, point to New, and then click DWORD Value.

12. Type PPPProtocolType, and then press ENTER.

13. On the Edit menu, click Modify.
14. Type 21, and then click OK.

15. On the Edit menu, point to New, and then click DWORD Value.

16. Type ProtocolMTU, and then press ENTER.
17. On the Edit menu, click Modify.

18. Type the appropriate MTU size (decimal value), and then click OK.

19. Quit Registry Editor.
Restart the computer for the changes to take effect

on May 25, 2008 | Microsoft Windows Vista Home Premium with...

1 Answer

Not enough mtu to go to xbox live at hotel


An MTU is the largest physical packet size, measure in Bytes that a network is capable of transmitting.. If messages are larger than the MTU they are divided into smaller packets before they can be sent. All networks have different MTU's which the owner of the network set at what they want to set it at. 576 is a very common MTU if you connect through PPP. 1500 is the most common MTU for Ethernet connections. The Xbox Live system requires your network to have a certain Maximum Transmission Unit (MTU). MTU values are important to the performance of online games. If this test fails, you can adjust the MTU setting on your network router or equivalent device to resolve the problem. Xbox live requires the network you use to have a maximum MTU. This is key to online gamesing. If the MTU fails then you have to adjust the router you are using. If you cannot access the router to adjust the MTU the you will not be able to play online games.

Mar 22, 2011 | Microsoft Xbox 360 Console

1 Answer

I need to change the MTU settings


To change your MTU settings download a program called DrTCP (google for it) then change the MTU size of your Internet connection, try 1465 and keep dropping it until you get a figure that works...

You can also check out xbox support site for more information on MTU settings here

Feb 23, 2010 | Arris SURFboard SBG900 Wireless Router...

1 Answer

What is the mtu and can it be changed?


To change the mtu you have to login to the web page of the modem and from there you will have an option to change the mtu. The default will be 1492 , change that to 1400 or 1358 for reliable communication with the x-box.

Dec 06, 2009 | Efficient Networks SpeedStream 5360...

1 Answer

Mtu setting


In some cases, MTU is not necessary to adjust. Its always automatic and defaulted to 1500. The router model that you have doesn't have MTU settings. You can download the User's Manual HERE. You must do port forwarding and open the xbox live port so you can play xbox live. If it keeps on telling you about MTU, you must set static IP address on your xbox's settings and power cycle your devices.

Jun 02, 2009 | Zhone (6218-I2-200) Router

1 Answer

Xbox live MTU failure


The reason why you're getting an MTU error is because the MTU has already reached the maximum # of packets that are being sent. To resolve it.
Access the GUI of your Linksys Router and go to the MTU settings. Set it to 1500. The lower, the better

Apr 26, 2009 | Linksys Wireless-G WRT54GS Router...

1 Answer

Needs to know more about MTU size changes


Changing the MTU size to any "small" value is a bad idea -- compare it to running to the corner store every time that you need to take anything (milk, ice-cube) out of your refrigerator -- the "time" to go back-and-forth to the store (or the Internet) will be excessive, and "slow" down your productivity.

Aug 04, 2008 | NetGear DG814 DSL Modem Internet Gateway...

1 Answer

I have 20mb broadband but only 300kbs download speed


I personally have never known that changing the MTU setting can speed up your connection, as the MTU is the maximum transmition units that is sent to your pc from each web site and if the MTU setting is incorrect then some web sites will not load on your explorer page, the speed at which you download the page will not make any difference.

If you are supposed to get 20MB speed then you must be on cable and not ADSL as ADSL is a max of 8MB, so i would ring up Virgin or whoever and check the speed you should really be getting.

See these details posted on the netgear site, and you'll notice there is no mention of speed:-

Details About MTU
A packet sent to a device larger than its MTU is broken into pieces. Ideally, MTU would be set to the same — large — value on all your computers, routers and switches, as well as on all the parts of the Internet that you access. But you cannot control the MTU on the Internet, and in practice the optimum MTU size on your LAN is related to your hardware, software, wireless interference, etc.
  • Tweaking MTU size may work well in one situation, but cause performance and connection problems in others.
  • When network devices with different MTU settings communicate, packets are fragmented to accommodate the one with the smallest MTU.
  • Windows XP sets MTU automatically, that is, it optimizes computer MTU for you. This Microsoft article explains resolving lack of connection to a broadband ISP using Windows XP: How-To Configure Broadband Connections Using PPPoE.
  • Once a network device fragments a packet, the data stays fragmented until arriving at the destination computer.
Setting MTU size is a process of trial-and-error: start with the maximum value of 1500, then reduce the size until the problem goes away. Using one of these values is likely to solve problems caused by MTU size:
  • 1500. The largest Ethernet packet size; it is also the default value. This is the typical setting for non-PPPoE, non-VPN connections. The default value for NETGEAR routers, adapters and switches.
  • 1492. The size PPPoE prefers.
  • 1472. Maximum size to use for pinging. (Bigger packets are fragmented.)
  • 1468. The size DHCP prefers.
  • 1460. Usable by AOL if you don't have large email attachments, etc.
  • 1430. The size VPN and PPTP prefer.
  • 1400. Maximum size for AOL DSL.
  • 576. Typical value to connect to dial-up ISPs.

Nov 22, 2007 | Microsoft Windows XP Home Edition

1 Answer

MTU


MTU, Partial Loss of Internet Connection, and Performance MTU (Maximum Transmission Unit) is the largest packet a network device transmits. The best MTU setting for NETGEAR equipment is often just the default value. MTU is sometimes presented as something that can be easily changed to improve performance, but in practice this may cause problems. Leave MTU unchanged unless one of these situations applies: 1. You have problems connecting to your ISP or other Internet service, and their technical support (or NETGEAR's) recommends changing MTU. For example, these services may require an MTU change: * Yahoo email * MSN * AOL's DSL service 2. You use VPN, and have severe performance problems. 3. You used a program to "optimize" MTU for performance reasons, and now you have connectivity or performance problems. * An easy solution to most problems is to change MTU to 1400. * If you are willing to experiment, gradually reduce MTU as described in "Details of MTU", below. How to Change a Computer's MTU Size Note: If you change MTU on one computer, it is likely you will want to change it on your other computers, switches, and routers, as well. Instructions for changing MTU on other NETGEAR devices is found in the Reference Manuals. The third party Dr. TCP software can be used to change the MTU setting. 1. Download it from this link, choosing the zip file or the exe file at the top of the page. 2. Run the utility. 3. In the Adapter Settings pull down, select the Ethernet driver and adapter used to connect with the network. 4. In the MTU box, type the MTU size you are trying. 5. Click in any other box, without changing the data there. 6. Click Save. 7. Click Exit. 8. Restart the computer. Details About MTU A packet sent to a device larger than its MTU is broken into pieces. Ideally, MTU would be set to the same ? large ? value on all your computers, routers and switches, as well as on all the parts of the Internet that you access. But you cannot control the MTU on the Internet, and in practice the optimum MTU size on your LAN is related to your hardware, software, wireless interference, etc. * Tweaking MTU size may work well in one situation, but cause performance and connection problems in others. * When network devices with different MTU settings communicate, packets are fragmented to accommodate the one with the smallest MTU. * Windows XP sets MTU automatically, that is, it optimizes computer MTU for you. This Microsoft article explains resolving lack of connection to a broadband ISP using Windows XP: http://www.microsoft.com/windowsxp/using/networking/learnmore/ppoe.mspx * Once a network device fragments a packet, the data stays fragmented until arriving at the destination computer. Setting MTU size is a process of trial-and-error: start with the maximum value of 1500, then reduce the size until the problem goes away. Using one of these values is likely to solve problems caused by MTU size: * 1500. The largest Ethernet packet size; it is also the default value. This is the typical setting for non-PPPoE, non-VPN connections. The default value for NETGEAR routers, adapters and switches. * 1492. The size PPPoE prefers. * 1472. Maximum size to use for pinging. (Bigger packets are fragmented.) * 1468. The size DHCP prefers. * 1460. Usable by AOL if you don't have large email attachments, etc. * 1430. The size VPN and PPTP prefer. * 1400. Maximum size for AOL DSL. * 576. Typical value to connect to dial-up ISPs.

Feb 19, 2006 | NetGear DG814 DSL Modem Internet Gateway...

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