Orange Bright Box: Set the MTU value to anything you like!

1. With MTU at its default "max" of 1492, run ping -f -l 1472 bbc.co.uk. It should fail with "Packet needs to be fragmented but DF set."
2. With MTU = 1500 (which is the max it can be, in case you don't know) by your method, again run ping -f -l 1472 bbc.co.uk. It should no longer fail.

In reply to a post by XRaySpeX:

But can you be sure that you have allowed the router to operate with MTU > 1492 everywhere? All you have shown is that the user can input such values and that they are stored, but how do you know that the router does not restrict the MTU elsewhere in its operation, like packaging packets?

You showed earlier that the code contains 11 tests for MTU > 1492 spread over 3 files. I would expect that the field input and storage of the MTU value, which you address here, would require no more than 2 tests. So what are the other 9 tests restricting?

The only way to prove that you have successfully allowed that you can have MTU > 1492 is:

1. With MTU at its default "max" of 1492, run ping -f -l 1472 bbc.co.uk. It should fail with "Packet needs to be fragmented but DF set."
2. With MTU = 1500 (which is the max it can be, in case you don't know) by your method, again run ping -f -l 1472 bbc.co.uk. It should no longer fail.

FYI: The number in the ping is required MTU-28.

Edited by glossywhite (Wed 08-Feb-12 14:09:47)

In reply to a post by glossywhite:

after changing to "1500", all pings timed out

In reply to a post by glossywhite:

after changing to "1500", all pings timed out (using Windows CMD... I'm an Ubuntu guy).

In reply to a post by XRaySpeX:

In reply to a post by glossywhite:

after changing to "1500", all pings timed out (using Windows CMD... I'm an Ubuntu guy).

Ah, I see! On Linux ping -D -s 1472 bbc.co.uk should run OK!

SG TCP/IP Analyzer

IP Address: 95.148.XXXXXXX (95.148.XXXXXXX)
Client OS: Linux
Browser: Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:10.0) Gecko/20100101 Firefox/10.0
Please Read the Analyzer FAQ if the above is not your IP address.
TCP options string = 020405b40402080a0019424f0000000001030307
MTU = 1500
MTU is fully optimized for broadband.
MSS = 1460
Maximum useful data in each packet = 1448, which is less than MSS because of Timestamps, or other TCP/IP options used.
Default TCP Receive Window (RWIN) = 14720
RWIN Scaling (RFC1323) = 7 bits (scale factor: 2^7=128)
Unscaled TCP Receive Window = 115

Under many Linux distributions, the Analyzer only shows the Current TCP Window. FAQ
RWIN seems to be set to a very small number. If you're on a broadband connection, consider using a larger value.
For optimum performance, consider changing RWIN to a multiple of MSS.
Other RWIN values that might work well with your current MTU/MSS:
64240 (up to 2 Mbit lines, depending on latency. MSS * 44)
128480 (1-5 Mbit lines, depending on latency. MSS * 44 * 2)
256960 (2-14 Mbit lines, depending on latency. MSS * 44 * 2^2)
513920 (8-30 Mbit lines, depending on latency. MSS * 44 * 2^3)
1027840 (25-60 Mbit lines depending on latency. MSS * 44 * 2^4)
bandwidth * delay product (Note this is not a speed test):

Your TCP Window limits you to: 589 kbps (74 KBytes/s) @ 200ms
Your TCP Window limits you to: 236 kbps (29 KBytes/s) @ 500ms
Consider increasing your RWIN value to optimize TCP/IP for broadband.
MTU Discovery (RFC1191) = ON
Time to live left = 47 hops
TTL value is ok.
Timestamps (RFC1323) = ON
Note: Timestamps add 12 bytes to the TCP header of each packet, reducing the space available for useful data.
Selective Acknowledgements (RFC2018) = ON
IP type of service field (RFC1349) = 00000000 (0)

Edited by glossywhite (Wed 08-Feb-12 15:14:45)

Edited by glossywhite (Wed 08-Feb-12 17:12:57)

In reply to a post by glossywhite:

How does this thread become removed?

In reply to a post by glossywhite:

Default TCP Receive Window (RWIN) = 14720

SYSTEM
Runtime Code Version: v0.09.82.0001-OT (Mon Nov 28 17:30:50 2011)
Boot Code Version: v1.00.10.0001-OT (Wed Dec 14 09:30:42 2011)
ADSL Modem Code Version: A2pD035b.d23i
Hardware Version: 01

Boot Code Version: v1.00.09.0002-OT (Wed Nov 9 10:21:21 2011)

In reply to a post by XRaySpeX:

This hack was fallacious and was withdrawn by OP.

However, we recently discovered that later Brightboxes issued allowed MTUs up to 1500.

The Brightbox without the MTU <= 1492 restriction has these versions:

SYSTEM
Runtime Code Version: v0.09.82.0001-OT (Mon Nov 28 17:30:50 2011)
Boot Code Version: v1.00.10.0001-OT (Wed Dec 14 09:30:42 2011)
ADSL Modem Code Version: A2pD035b.d23i
Hardware Version: 01

The one that has the restriction is almost the same except for:

Boot Code Version: v1.00.09.0002-OT (Wed Nov 9 10:21:21 2011)

It looks like 1 month after releasing it, Orange realised that MTU = 1492 was not sufficient for WBC where MTU = 1500 and so started to push out ones with updated firmware. Tho' their version control looks wanting as the relevant code restricting MTU is in the Runtime.

Orange have not yet issued a firmware update for the older Brightboxes, but they tell me that they may issue an update in the future and I should await an email annoucing it. Oh, the joys of being an early adopter !

Firmware Upgrade
Browse to the location of the upgrade file. Then press the begin upgrade button.

File ___________________________ Browse

In reply to a post by E7er:

will your router update to this version?
http://help.orange.co.uk/orangeuk/support/personal/6...

Edited by XRaySpeX (Wed 27-Jun-12 13:16:22)

In reply to a post by XRaySpeX:

Sorry, I don't understand you. What Update Software page? I only have Tools -> Firmware Upgrade, which wants a local file and simply looks like this:

Firmware Upgrade
Browse to the location of the upgrade file. Then press the begin upgrade button.

File ___________________________ Browse

In reply to a post by E7er:

will your router update to this version?
http://help.orange.co.uk/orangeuk/support/personal/6...

What version? Where do I find it? There is no download any firmware on that Orange page.

In reply to a post by E7er:

you can see from that page there is a facility to update the bootloader firmware. You will just have to wait for Orange to provide it.

In reply to a post by XRaySpeX:

Yes, but obviously, I don't have that page, which must be in your firmware but not mine; just that simple page I sketched out.

In reply to a post by XRaySpeX:

What happens if you try set MTU to 1501?

Do you get same unsupported msg as me but with 1492 replaced by 1500?

Edited by deleted (Sun 01-Jul-12 01:53:40)

MTU (576~1492) ____

In reply to a post by XRaySpeX:

In which case you won't have the bracketed limits on Set-Up page for MTU:

MTU (576~1492) ____

In reply to a post by XRaySpeX:

Are you still on 6dB?

In reply to a post by XRaySpeX:

6.6db now almost certainly means 6dB Target NM set at sync time.

In reply to a post by XRaySpeX:

Yeah! 5.7 dB in the nighttime; 6.6 dB in daylight ... no surprises there then!

Edited by deleted (Thu 05-Jul-12 14:46:27)

In reply to a post by XRaySpeX:

Has it resynced since last night?

Maybe DLM is trying to put you on Target NM of 3 DB (which I'm on).

In reply to a post by Mozzerr:

Agreed, the DLM must now have set the target NM to 3db given this morning's figures

In reply to a post by XRaySpeX:

And the consequences are what? How does this affect the user?

What does this have to do with the Subject?

In reply to a post by XRaySpeX:

So you take it apart to find out rather than just feed 1500 into the MTU field? How quaint!

Edited by glossywhite (Tue 28-Aug-12 22:49:14)

In reply to a post by XRaySpeX:

...

Show me 1 hardware hack you've achieved that has made this thing do something useful that it didn't do before.

Edited by glossywhite (Wed 29-Aug-12 07:02:49)

In reply to a post by XRaySpeX:

As I said, I've no interest in the hardware, which is your speciality.

The idea of forums is to bring together many diff areas of expertise to bear on a common problem, not to try and indoctrinate others to your pet subject.

In reply to a post by XRaySpeX:

This hack was fallacious and was withdrawn by OP.

However, we recently discovered that later Brightboxes issued allowed MTUs up to 1500.

The Brightbox without the MTU <= 1492 restriction has these versions:

SYSTEM
Runtime Code Version: v0.09.82.0001-OT (Mon Nov 28 17:30:50 2011)
Boot Code Version: v1.00.10.0001-OT (Wed Dec 14 09:30:42 2011)
ADSL Modem Code Version: A2pD035b.d23i
Hardware Version: 01

The one that has the restriction is almost the same except for:

Boot Code Version: v1.00.09.0002-OT (Wed Nov 9 10:21:21 2011)

It looks like 1 month after releasing it, Orange realised that MTU = 1492 was not sufficient for WBC where MTU = 1500 and so started to push out ones with updated firmware. Tho' their version control looks wanting as the relevant code restricting MTU is in the Runtime.

Orange have not yet issued a firmware update for the older Brightboxes, but they tell me that they may issue an update in the future and I should await an email annoucing it. Oh, the joys of being an early adopter !

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youtube@i3:~/Desktop/backup_of_BrightBox_MTDs$ ls
bootloader  manuf  nvram  pricfg  priimg  rootfsyoutube@i3:~/Desktop/backup_of_BrightBox_MTDs$ strings -f * | grep "17:30:50"
priimg: ArcMagicSignature;date=Mon Nov 28 17:30:50 2011;ver=v0.09.82.0001;rootfs: ArcMagicSignature;date=Mon Nov 28 17:30:50 2011;ver=v0.09.82.0001;
youtube@i3:~/Desktop/backup_of_BrightBox_MTDs$

Edited by glossywhite (Sun 09-Sep-12 03:25:02)

In reply to a post by glossywhite:

It looks like ONLY the bootloader is updated... but I haven't delved deep enough... yet

Edited by XRaySpeX (Sun 09-Sep-12 21:45:59)

System
Runtime Code Version: v0.09.94.0006-OT (Fri Sep 21 03:00:26 2012)
Boot Code Version: v1.00.09.0002-OT (Wed Nov 9 10:21:21 2011)
ADSL Modem Code Version: A2pD035b.d23i
Hardware Version: 01

In reply to a post by XRaySpeX:

With the deployment of the new EE firmware, the MTU can now be set up to 1500.

The new versions are:

System
Runtime Code Version: v0.09.94.0006-OT (Fri Sep 21 03:00:26 2012)
Boot Code Version: v1.00.09.0002-OT (Wed Nov 9 10:21:21 2011)
ADSL Modem Code Version: A2pD035b.d23i
Hardware Version: 01

Note that it is the Runtime Code Version that has increased, as you would expect, not the Boot Code Version.