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2820Vn Firmware v3.3.4.1 available on draytek.com

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20 Oct 2010 10:01 #64313 by damienf
Replied by damienf on topic 2820Vn Firmware v3.3.4.1 available on draytek.com
does anyone knows where an MTU of 1442 comes from ?
I've read that 1454 was the 'ideal' MTU for a PPPoE/ADSL, and 1478 for PPoA/ADSL.

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20 Oct 2010 10:11 #64314 by njh
Replied by njh on topic 2820Vn Firmware v3.3.4.1 available on draytek.com

gruffle wrote: required mtu setting can be different according to your telephone exchange hardware. There are utilities for this if you search around but a
quick way to check the mtu you should be using:

ping -f -l nnnn hostname

(-l is letter l not digit 1)
eg
ping -f -l 1442 google.com

keep increasing number until timeout or cant fragment msg.


Don't you then adjust this for the packet headers? See here , although going with a lower value won't cause any problems.
2900Gi/v2.5.6; 2900/v2.5.6

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20 Oct 2010 23:24 #64328 by gruffle
Replied by gruffle on topic 2820Vn Firmware v3.3.4.1 available on draytek.com
oops - thanks -missed that bit off

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21 Oct 2010 22:33 #64363 by jchamier
Replied by jchamier on topic 2820Vn Firmware v3.3.4.1 available on draytek.com

NJH wrote: The MTU for ADSL should never be higher than 1492. 1500 is for cable/ethernet.



That 1492 assumes your ADSL is using PPPoE which in the UK is not very common.

If your provider uses BTwholesale then BT recommend PPPoA and 1500 byte MTU - also with BE and O2's LLU services which don't use PPPoA but use ETHoA then also 1500 - all on the router.

Lowering MTU on your PC can improve connections. Lowering on the router without lowering on the PC can make connections really bad. (esp wireless).
Vigor2820Vn - BT Infinity 2 - Download: 45 megabit/sec - Upload: 8 megabit/sec

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21 Oct 2010 23:06 #64365 by rothers
Replied by rothers on topic 2820Vn Firmware v3.3.4.1 available on draytek.com
MTU of 1500 works for me on C&W LLU (Demon) PPPoA

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23 Oct 2010 17:19 #64380 by dac
Replied by dac on topic 2820Vn Firmware v3.3.4.1 available on draytek.com
Had seemingly the same problem. After 3.3.4.1, download speeds dropped from 11 meg down to 1.5. Changed the firmware back and it was as right as rain again. My router has far too many config changes to consider setting it to factory default and reapplying them, so I'll wait until they have a stable firmware with a working upgrade path.

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