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Maximum Bandwidth v's Bandwidth

keenfamily
Dabbler
Posts: 21
Registered: 20-01-2012

Maximum Bandwidth v's Bandwidth

is my maximum bandwidth supposed to show that it is lower than my actual bandwidth?
Link Information
Uptime: 0 days, 8:38:19
DSL Type: G.992.5 annex A
Maximum Bandwidth (Up/Down) [kbps/kbps]: 1,204 / 12,756
Bandwidth (Up/Down) [kbps/kbps]: 1,215 / 13,304
Data Transferred (Sent/Received) [MB/MB]: 56.19 / 281.31
Output Power (Up/Down) [dBm]: 12.0 / 20.5
Line Attenuation (Up/Down) [dB]: 11.5 / 27.0
SN Margin (Up/Down) [dB]: 6.0 / 8.5
Vendor ID (Local/Remote): TMMB / IFTN
Loss of Framing (Local/Remote): 0 / 0
Loss of Signal (Local/Remote): 0 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 10 / 0
FEC Errors (Up/Down): 93,056 / 0
CRC Errors (Up/Down): 9,045 / 2,952
HEC Errors (Up/Down): NA / 7,068
6 REPLIES
Community Veteran
Posts: 38,460
Thanks: 1,027
Fixes: 62
Registered: 15-06-2007

Re: Maximum Bandwidth v's Bandwidth

Now that is unusual.
I haven't seen that before - it must be the way your router calculates things
houlton23
Grafter
Posts: 268
Registered: 22-05-2011

Re: Maximum Bandwidth v's Bandwidth

Quote from: Oldjim
it must be the way your router calculates things

Maybe it is taking into account the target SNRM of 9db and calculating how much speed it thinks you would loose were you to resync?
Community Veteran
Posts: 6,313
Thanks: 86
Fixes: 3
Registered: 08-01-2008

Re: Maximum Bandwidth v's Bandwidth

Many routers calculate the Maximum Bandwidth based on a reference SNR Margin (usually 6dB), although the figures above indicate a current margin of 6dB that's likely to be rounded to 0.5dB (some routers display to nearest 0.1 dB and others round to whole numbers), your SNR  margin is probably slightly lower then 6dB (but not low enough to be rounded to 5.5) so it calculates the likely speed you'd get if you resynced at a 6dB target margin.
Some routers (2-Wire HGV2700 for example) seem to be aware of current target margin (or estimate it from the last sync) and calculate the 'maximum' bandwidth based on this.
[EDIT] sorry, I read the 'Up' figures rather than 'Down' but the same pretty much applies
Call me 'w23'
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niko
Grafter
Posts: 199
Registered: 30-01-2012

Re: Maximum Bandwidth v's Bandwidth

i see its been up for 8 hours ,could it be the last re sync wasn't a hard reboot and that's the overall figure for the line
another way of putting it ,maybe it would show correctly after hard rebooting the router
keenfamily
Dabbler
Posts: 21
Registered: 20-01-2012

Re: Maximum Bandwidth v's Bandwidth

I did a hard rebot of the router 8 hours ago to see if it would sort it after it had been that way for 5 days.
but it did'nt help Smiley
Superuser
Superuser
Posts: 9,583
Thanks: 958
Fixes: 55
Registered: 06-04-2007

Re: Maximum Bandwidth v's Bandwidth

In my experience Maximum Bandwidth being less than the current Bandwidth is nothing unusual, mine is presently and usually is after dark. I don't know how the router works Maximum Bandwidth out but I assume scope for bit-swapping is probably taken into consideration as well as current vs target noise margin.
David