RE: question about MPE and AAL5 over satellites

[<Matti.Puputti@nokia.com>]

Hi Raf,

 

I'm not familiar with AAL5, and do not have the specification available.

However, about MPE I can tell following:

Length of an MPE section is indicated with 12 bits, and shall not exceed 4093 (Bytes).

Overhead caused by the MPE section header is 13 Bytes, leaving 4080 Bytes for the payload.

 

As one datagram may be divided on max 256 sections, the absolute maximum size for Layer 3 datagram carried on MPE is (256 * 4080) = 1 044 480 Bytes.

 

However, in case of IP datagrams, one datagram shall be delivered in a single MPE section.

This results the maximum size of an IP datagram being 4080 Bytes.

 

Matti Puputti, Senior System Specialist
Nokia Ventures Organization/IPDC
P.O.Box 4, FIN-20521 TURKU
Phone: +358 7180 33473, Fax: +358 7180 33 232
Mobile: +358 50 383 4683
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