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New Member

dsl ping times

Will there be any differences in ping times in the following scenarios?

1. PPPoA (ADSL-over-POTS USB modem)

2. PPPoA (ADSL-over-POTS ETH modem)

3. PPPoA (ADSL-over-ISDN USB modem)

4. PPPoA (ADSL-over-ISDN ETH modem)

5. PPPoE (ADSL-over-POTS USB modem)

6. PPPoE (ADSL-over-POTS ETH modem)

7. PPPoE (ADSL-over-ISDN USB modem)

8. PPPoE (ADSL-over-ISDN ETH modem)

How about the fastest one?

5 REPLIES
Cisco Employee

Re: dsl ping times

There are no such hard data available for all those ping times based on thos technologies..It all depends on the speed of the dsl modem trained at and also the internet delay which varies a lot.

New Member

Re: dsl ping times

Sorry to disagree with tepatel but the main difference is not the modem type but how the DLAM (and the modem/router) is set to handle the data. ADSL can be set on fast or interleaved and guess what fast is faster :-)

From the cisco 1751 (Iuse) show dsl interface atm1/0:

Read on 5 columns:

// // Interleave // Fast // Interleave // Fast

Speed (kbps): // 832 // 0 // 192 // 0

Reed-Solomon EC: // 0 // 0 // 1 // 0

CRC Errors: // 0 // 0 // 0 // 0

Columns 2&3 is the dowstream channel and 4&5 is the upstream one

Therefore a good question to ask to the provider is how the ADSL is configured (fast or interleaved). In any case PPPoE has an additional 8 byte-header prepended, therefore it has a slightly higher overhead.

New Member

Re: dsl ping times

So until now we have PPPoA better than PPPoE.

What about USB vs ETH modems? Will there be any difference?

What i'm trying to do is find which one is the better connection for online gaming.

ISDN TA (PCI) gives 25ms for the first hop and i believe ADSL won't easily beat this.

Cisco Employee

Re: dsl ping times

I do agree all that but it mainly depends on the dsl modem upstream and downstream trainup speed which is basic right? Ofcourse you can limit that in the DSLAM as the physical layer termination of the dsl line is at dslam.

Also 8 bytes of higher overhead will not impact at all on the ping times though. So the bottom line is we need to know what is the purpose behind to know the ping times?

New Member

Re: dsl ping times

Just to see which one is the best for online gaming....

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