"Gustavo Marsico [Gmail]" <gustavomarsico at gmail.com> writes:
> It's talking about Japan:
>
> Note: In the ITU-T Japan variant, signaling link quality is checked by the
> continuous transmission of flag octets (8-bit bytes) rather than FISUs;
> FISUs are sent only at predefined timer intervals (e.g., once every 150
> milliseconds).
>
> If you live in Japan can make sense that, but in ITU world it's just like as
> Kristian's said.
Yes, I meant ITU SS7. Forgot about the multiple variants ...
Here is the relevant quote from ITU Q.703:
11.2.2 For the basic error control method, the priorities are:
Highest 1. Link status signal units.
2. Message signal units which have not yet been acknowledged and for which a
negative acknowledgement has been received.
3. New message signal units.
4. Fill-in signal units.
Lowest 5. Flags.
So fill-in signal units are sent unless some serious error prevents sending
anything but flags.
Don't know about any other variants of SS7.
- Kristian.
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