O2User: What are router stats?

What are router stats?
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NewsreadeR on 23 November, 2008 02:18:00
 
Stats?
Your ADSL router constantly monitors your line and connection and stores the
results. These results or stats can be very helpful in determining whether your
connection is performing as it should and importantly, if things are changing
over time.
Where do I find them?
Well that depends on which router you are using - each manufacturer has a
different process to display them and in some cases, ISPs change the router
firmware to make them not visible to the customer.
Also, you may see people referring to "simple stats" and "detailed stats".
Simple are the basic router connection stats of sync, noise margin (snr) and
attenuation. Detailed stats include a number of other parameters including line
error counts.
Simple stats are usually available through logging ito the router admin pages.
If you are using the O2 Wireless box then the router admin pages can be accessed
via http://192.168.1.254.
To quote O2, "when you first receive your O2 wireless box it is set to a default
username and password to allow you quick and easy access without any need for
additional usernames and passwords". This means access to the Box is wide open
so you are strongly recommended to set a password to restrict access. To do this
go to "User Management" and next to Administrator choose "Change my password".
You'll now be presented with three blank fields. In the first "Old Password"
leave it blank, in the other two type your new password. After confirming you'll
then be asked to enter your username and password. These will now be
Administrator (note the capital A) and the password you've previously entered.
You now have access to a number of functions within the router.
The detailed stats are not available with this login and a "secret" superuser
account must be used. To access the superuser account, log in to the router
again but this time with username SuperUser (note the capital S and U) and
password O2Br0ad64nd (thats digits 2064 and the first O and B being capital
letters).
OK I've found the stats but what do they mean?
With the O2 Box your detailed stats will look something like this:
Uptime: 0 days, 1:39:16
DSL Type: G.992.5 annex A
Bandwidth (Up/Down) [kbps/kbps]: 949 / 10,543
Data Transferred (Sent/Received) [kB/kB]: 0.00 / 0.00
Output Power (Up/Down) [dBm]: 12.0 / 19.0
Line Attenuation (Up/Down) [dB]: 18.5 / 38.0
SN Margin (Up/Down) [dB]: 6.5 / 7.0
Vendor ID (Local/Remote): TMMB / BDCM
Loss of Framing (Local/Remote): 116 / 0
Loss of Signal (Local/Remote): 36 / 0
Loss of Power (Local/Remote): 0 / 0
Loss of Link (Remote): 0
Error Seconds (Local/Remote): 80 / 0
FEC Errors (Up/Down): 28 / 27,211
CRC Errors (Up/Down): 28 / 131
HEC Errors (Up/Down): 194,652 / 121
The important ones are as follows:
*Bandwidth (sync)	*Line Attenuation	*SN Margin	*Loss of Framing	*Loss of
Signal	*Error Seconds	*CRC Errors
CRC (Cyclic Redundancy Check).
Data is transmitted as streams of packets through a network. A TCP module at the
far end sends back an acknowledgement for packets which have been successfully
received. It checks for damaged bytes by using a checksum. In simple terms, if
any packets fail the check they will be recorded as CRC errors.
The number of CRC errors recorded must be looked at in relation to the total
amount of data transmitted and the time period covered. Unfortunately there is
no standard formula which would indicate whether a given level of CRC is
acceptable or unacceptable.
In any event CRC must not be looked at in isolation; it is quite possible for
instance to have a "low" level of CRC but a high level of errored seconds/loss
of signal and vice versa.
LOS (Loss of signal)
This sounds bad but a handfull of these in any 15 minute period will probably go
unnoticed in normal surfing/downloading. It's showing that connection to the
exchange was lost momentarily but the connection will cope with this. A high
level however, say more than 5% of the CRCs, indicates a fairly severe line
problem, possibly noise spiking.
ES (Errored Seconds)
An Errored Second is a second in which one or more coding violations occurred OR
one or more loss of signal defects occurred.
Again, as with CRC there is no standard formula which would indicate whether a
given level of ES is acceptable or unacceptable. Anything other than a near
perfect line will give some level of ES error. Look at the 15 minute periods.
There are 900 seconds in 15 minutes. An errored second figure of up to 5 or 10
is probably manageable. On really bad lines the ES number can actually equal the
total seconds i.e. every second of connection experienced a coding violation or
loss of signal.
In many ways, errored seconds are a better indicator of a line that is
struggling than CRC.
One last thing. A caveat on the above:
Interpretation is down to subjective evaluation - you can't simply say "this is
good - that's bad". The whole picture must be looked at.
When looking at the stats, particular attention must be paid to the noise margin
levels during the stat measurement period. For example, if the noise margin had
dropped down to less than 6db then even the best quality line would record
errors. Similarly, if the noise margin had been boosted up so it was always
above say 9db and the line showed errors, then the "real" error level will have
been under reported.
Interpreting stats can be a bit of a "black art". Please copy and past them into
a post if asked or if you feel you have connection problems.