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DSL Controllers configuration - Noob inside

gesnaudniji
Beginner
Beginner

Hello dear community,

I never configured ATM or DSL interface, but i need to know hat the configured rate line interface stand for?

Because, even on a 2 or 4 -Wire configuration, sometimes the addition of the line-0 rate and line-1 rate is less or superior to the configured line rate value (and so on for the line-2 and line-3 on 4-wire config.)... To add to my misunderstood, sometimes the confiured line rate is in auto mode... so How the routeur know what the rate is?

Cheers,

Greg

1 Accepted Solution

Accepted Solutions

mavespig
Participant
Participant

Hi Greg,

on xDSL CPEs, the line speed is set by the DSLAM, based on line conditions, DSLAM config, etc.

Since you are writing about 4-wires, I assume that you  have a SHDSL card. In that case, the card can be configured as CPE or  as CO. When the card is in CO mode, you can force the line to work at a  specific speed.

Let me know if this answers your question.

Cheers

Marco

View solution in original post

9 Replies 9

mavespig
Participant
Participant

Hi Greg,

on xDSL CPEs, the line speed is set by the DSLAM, based on line conditions, DSLAM config, etc.

Since you are writing about 4-wires, I assume that you  have a SHDSL card. In that case, the card can be configured as CPE or  as CO. When the card is in CO mode, you can force the line to work at a  specific speed.

Let me know if this answers your question.

Cheers

Marco

Yeah, you illuminate my day

Just one point: why sometimes the configured line rate is less than the amount of the line rate?

And just to check if i understood well:

Configured.rate;line.rate.1;line.rate.2;line.rate.3;line.rate.3;My.comprehension

4608Kbps;1032Kbps;1032Kbps;null;null;"I can have a Max of 4608 but my operator has limited it to 2048Kbps (1032*2)"

Auto;1288Kbps;NULL;NULL;NULL;"I can have a Max of 1288Kbps, that the natural capacity of the line (Auto)"

2048Kbps;2056Kbps;NULL;NULL;NULL;"WTF?! I can have more than the capacity lines? Or it is a bad calculation?"

Thanks again!

Cheers,

Greg

From which command are you taking this output?

Can you take the output of "show controller shdsl" from the CPE?

(ok, i thought that if i have a 4-wire, i should find line 0, 1, 2 & 3. But actually 4-wire == line 0,1  and 2-wire == line 0 only... that's it?)

First CPE:

sh controllers dsl

DSL 0 controller UP

SLOT 0: Globespan xDSL controller chipset

Frame mode: Utopia

Configured Line rate: 4608Kbps

Line Mode: Four Wire Enhanced Mode

DSL mode: SHDSL Annex B

Line Re-activated 327 times after system bootup

LOSW Defect alarm: ACTIVE

CRC per second alarm: ACTIVE

Line termination: CPE

Line 0 statistics

        Current 15 min CRC: 0

        Current 15 min LOSW Defect: 0

        Current 15 min ES: 0

        Current 15 min SES: 0

        Current 15 min UAS: 0

        Previous 15 min CRC: 0

        Previous 15 min LOSW Defect: 0

        Previous 15 min ES: 0

        Previous 15 min SES: 0

        Previous 15 min UAS: 0

Line 1 statistics

        Current 15 min CRC: 0

        Current 15 min LOSW Defect: 0

        Current 15 min ES: 0

        Current 15 min SES: 0

        Current 15 min UAS: 0

        Previous 15 min CRC: 0

        Previous 15 min LOSW Defect: 0

        Previous 15 min ES: 0

        Previous 15 min SES: 0

        Previous 15 min UAS: 0

Line-0 status

Chipset Version:  0

Firmware Version:  R3.0.5

Modem Status:  Data, Status 1

Last Fail Mode:  No Failure status:0x0

Line rate:  1032 Kbps

Framer Sync Status: In Sync

Rcv Clock Status: In the Range

Loop Attenuation:  15.7 dB

Transmit Power:  13.5 dB

Receiver Gain:  25.5200 dB

SNR Sampling:  37.1390 dB

Line-1 status

Chipset Version:  0

Firmware Version:  R3.0.5

Modem Status:  Data, Status 1

Last Fail Mode:  No Failure status:0x0

Line rate: 1032 Kbps

Framer Sync Status: In Sync

Rcv Clock Status: In the Range

Loop Attenuation:  15.8 dB

Transmit Power:  13.5 dB

Receiver Gain:  20.2000 dB

SNR Sampling:  37.4390 dB

Dying Gasp: Present


Second CPE

sh controllers dsl

DSL 0 controller UP

SLOT 0: Globespan xDSL controller chipset

Frame mode: Utopia

Configured Line rate: Auto

Line Mode: Two Wire

DSL mode: SHDSL Annex B

Line Re-activated 0 times after system bootup

LOSW Defect alarm: ACTIVE

CRC per second alarm: ACTIVE

Line termination: CPE

        Current 15 min CRC: 0

        Current 15 min LOSW Defect: 0

        Current 15 min ES: 0

        Current 15 min SES: 0

        Current 15 min UAS: 0

        Previous 15 min CRC: 0

        Previous 15 min LOSW Defect: 0

        Previous 15 min ES: 0

        Previous 15 min SES: 0

        Previous 15 min UAS: 0

Line-0 status

Chipset Version:  0

Firmware Version:  R3.0.5

Modem Status:  Data, Status 1

Last Fail Mode:  No Failure status:0x0

Line rate:  1288 Kbps

Framer Sync Status: In Sync

Rcv Clock Status: In the Range

Loop Attenuation:  4.8 dB

Transmit Power:  11.5 dB

Receiver Gain:  18.7420 dB

SNR Sampling:  40.8380 dB

Dying Gasp: Present

Third CPE:

sh controllers dsl

DSL 0 controller UP

SLOT 0: Globespan xDSL controller chipset

Frame mode: Utopia

Configured Line rate: 2048Kbps

Line Mode: Two Wire

DSL mode: SHDSL Annex B

Line Re-activated 4 times after system bootup

LOSW Defect alarm: ACTIVE

CRC per second alarm: ACTIVE

Line termination: CPE

        Current 15 min CRC: 0

        Current 15 min LOSW Defect: 0

        Current 15 min ES: 0

        Current 15 min SES: 0

        Current 15 min UAS: 0

        Previous 15 min CRC: 0

        Previous 15 min LOSW Defect: 0

        Previous 15 min ES: 0

        Previous 15 min SES: 0

        Previous 15 min UAS: 0

Line-0 status

Chipset Version:  0

Firmware Version:  R3.0.5

Modem Status:  Data, Status 1

Last Fail Mode:  No Failure status:0x0

Line rate:  2056 Kbps

Framer Sync Status: In Sync

Rcv Clock Status: In the Range

Loop Attenuation:  8.7 dB

Transmit Power:  13.5 dB

Receiver Gain:  22.5420 dB

SNR Sampling:  42.880 dB

Dying Gasp: Present

thanks,

Hi Greg,

"Line rate" is actually the speed negotiated between CO and CPE.

Let me do a couple of examples:

1. CO set for 2048 and CPE set for auto --> line rate will be 2048

2. CO set for 2048 and CPE set for 1024 --> line rate will be 1024

3. CO set for 1024 and CPE set for 2048 --> line rate will be 1024

4. CO set for 2048 and CPE set for 2048 --> line rate will be 2048

The difference between 1 and 4 (auto vs. set speed) is that if line conditions are changing (or CO config is changed), CPE will automatically retrain to the right speed, when set in auto.

I see on your third CPE that apparently the line rate is 8Kbps faster than the configured one. This may be a cosmetic issue with the show command (e.g. unit rounded in the wrong way). If you set that CPE for auto, what is the line rate negotiated?

Cheers

Marco

I have not the hand on the CPE, so I can not modify config, sorry...

I thought i understood your explain, but i think that i missed an information. what is the CO? Is it the DSLAM? or the line-0, line-1 etc.?

ex:

(explain                    ==> sh run traduction)

CPE set for 2048     ==> "Configured Line rate: 2048Kbps"

CO set for 1024       ==> "Line-0 status[...]Line rate:  512 Kbps"

                                     "Line-1 status[...]Line rate: 512 Kbps"

Thanks again,

Greg

CO stands for Central Office, and it's basically the DSLAM in SHDSL plants.

For your reference:

you can connect two cisco routers with SHDSL cards back-to-back.

Router A --- (shdsl) --- Router B

In that case, you will need to configure "mode co" on one side, and "mode cpe" on the other. The config is applied under the shdsl controller.

Hope this answers your question

Marco

Well, I'm close to a full comprehension

So my controllers DSL are configured in CPE Mode (line term CPE I guess?).

Sometimes, DSL controllers are configured in auto, that means the rate is negotiated with the CO, and I can gues the rate by the addition of all the line rate (line-0, line-1 etc.), right?

Other times, DSL controllers are configured with a static rate, that means the rate is NOT negotiated with the CO, and I can gues the real rate of the line by the lowest value beetween DSL configured line rate and line rate addition (that is the CPO <-> CPE speed)?

1.CO set for 2048 and CPE set for auto  --> line-0+line-1+... = rate will be 2048

2. CO set for 2048 and CPE set for 1024 --> sum(line-n) = line rate will be 1024

3. CO set for 1024 and CPE set for 2048 --> sum(line-n) = line rate will be 1024

4. CO set for 2048 and CPE set for 2048 --> sum(line-n) = line rate will be 2048

Thanks a lot again and again

Hi Greg, all correct, except for a little one:

Line rate negotiation will happen in every case.

If your router is configured with a forced rate, your router will tell the DSLAM what's the max speed that it can afford.

You're welcome!

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