Hi Everyone,
So, I have a Cisco 877W router. Frankly I am not very proficient with IOS.
Configuration options on the ATM interface of the router has these goodies:
dsl operating-mode (4)
adsl2 ITU G.992.3 Annex A and L
adsl2+ ITU G.992.5 Annex A
ansi-dmt ANSI T1.413
auto auto detect mode
itu-dmt ITU G.992.1 Annex A
dsl noise-margin (7)
noise margin value -3 to 0 (1/2 dB/step)
dsl gain-setting tx-offset (14)
tranmit gain offset value -10 to 3 (1/2 dB/step)
dsl gain-setting rx-offset (9)
receive gain offset value -5 to 3 (1/2 dB/step)
dsl bitswap (3)
both Enable on both directions
downstream Enable for inbound data stream from DSLAM
upstream Enable for outbound data stream to DSLAM[/code]
The numbers in the brackets show the number of of options available that are of interest to me. Now with these options, a total 10,584 configuration combinations are possible.
Now in order to achieve the fastest and reasonably stable connection for my connection I cannot obviously try all of them on a trial-and-error basis. Given that I think I am baout 3km from the exchange, I'm already losing out just through attenuation.
Before I started playing around with this the best I was getting was around 1.5Mb/s. I have tried several DSL operating modes and improved speed by merely switching to itu-dmt.
I've tinkered with it more to achieve a bit under 3Mb/s with int ATM 0 having:
dsl operating-mode adsl2+
dsl noise-margin -0.5
dsl gain-setting tx-offset -10
dsl gain-setting rx-offset -5
dsl bitswap upstream
With sh dsl int atm 0 output being:
ATM0
Alcatel 20190 chipset information
ATU-R (DS) ATU-C (US)
Modem Status: Showtime (DMTDSL_SHOWTIME)
DSL Mode: ITU G.992.5 (ADSL2+) Annex A
ITU STD NUM: 0x03 0x2
Chip Vendor ID: 'STMI' 'IFTN'
Chip Vendor Specific: 0x0000 0x71B9
Chip Vendor Country: 0x0F 0xB5
Modem Vendor ID: 'CSCO' ' '
Modem Vendor Specific: 0x0000 0x0000
Modem Vendor Country: 0xB5 0x00
Serial Number Near: FGL153428Y 877W-G-A 15.1
Serial Number Far: Chip ID: C196 (3)
DFE BOM: DFE3.0 Annex A (1)
Capacity Used: 100% 99%
Noise Margin: 8.5 dB 12.0 dB
Output Power: 16.0 dBm 12.5 dBm
Attenuation: 56.0 dB 38.0 dB
FEC ES Errors: 0 0
ES Errors: 1 0
SES Errors: 1 0
LOSES Errors: 1 0
UES Errors: 0 128
Defect Status: None None
Last Fail Code: None
Watchdog Counter: 0x34
Watchdog Resets: 0
Selftest Result: 0x00
Subfunction: 0x00
Interrupts: 838836 (0 spurious)
PHY Access Err: 0
Activations: 609
LED Status: ON
LED On Time: 100
LED Off Time: 100
Init FW: init_AMR_6.0.010.bin
Operation FW: AMR-E-6.0.010.bin
FW Source: external
FW Version: 6.0.10
DS Channel1 DS Channel0 US Channel1 US Channel0
Speed (kbps): 0 3464 0 407
DS User cells: 0 9337
US User & Idle cells: 0 31843
Reed-Solomon EC: 0 0 0 0
CRC Errors: 0 0 0 0
Header Errors: 0 0 0 0
Total BER: 0E-0 0E-0
Leakage Average BER: 0E-0 0E-0
However, I would love to know what all the options mean, how I can collect and determine information about my connection between my router and the DSLAM and use this information to select and tweak the options mentioned above to optimise my connection for speed and stability.
Can any one shed any light? Direct me to resources that might help me out? Guide me what tests to run for each parameter available above and how to determine the best setting to use to achieve for fastest possible speed and at an acceptable stability (i.e. no drop-outs)?
Thank you in advance.
