[cisco-bba] "pure" data transfer rate

Anastassios Chatzithomaoglou achatz at forthnet.gr
Thu Aug 7 14:30:42 EDT 2003

Suppose we have the following cases:

1. PPP over PSTN 56 kbps (pstn modem)
2. PPP over ISDN 64 kbps (isdn ta)
3. PPP over ISDN 128 kbps (isdn ta)
4. PPPoA 384/128 kbps (ADSL modem)
5. PPPoE 384/128 kbps (ADSL modem)

What is the maximum transfer rate of pure data (no headers included) while uploading in 
each case using a specific packet size?

Is the following assumption correct?
If we have udp packets of 20 bytes each, then for case 2 the max pure data transfer rate 
will be:

(20 x 8) x 64000 / ((20 x 8) + (30 x 8)) = 25600 bps

where 30 bytes = UDP/IP/PPP headers

Or is there any LAPD framing that i should take note of?

    Chatzithomaoglou Anastasios
Network Design & Operations Center
           FORTHnet S.A.
       <achatz at forthnet.gr>

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