Retronetworking » OCTOI - Osmocom Community TDM over IP

{{>toc}}

h1. Type Of Number and Numbering Plan Indicator

In PSTN networks, calling and called party numbers are relatively simple: they just consist of a linear row of decimal digits.

In ISDN (and its cousin, the SS7 signaling network), _party_ identifiers are a tuple consisting of three components:

# the numbering plan indicator (NPI)

# the type of number (TON)

# a series of digits

When sending addresses (numbers) in an ISDN or SS7 network such as OCTOI, you have to make sure that the entire tuple of (NPI, TON, digits) is given in a meaningful way.  You cannot use an international number with trailing zeroes, or a national number with international prefix!

h2. Numbering Plan Indicator

h3. E.164

E.164 is the normal numbering plan in telephony.  It is specified in ITU-T Recommendation E.164, and it is what people normalyl consider a phone number.  It also is the specification for the familiar international prefixes like @49@ for Germany, @1@ for North America, etc.

h3. Unknown

This _Unknown_ type of number indicator is used if the type is unknonw to the sender.  This basically makes the interpretation of the dialled digits dependent on the context/location/position in the network.

h2. Type Of Number

h3. National

The _National_ type of number indicator is used to specify that the digits are in fully-qualified national format, including any national area code but *excluding* any prefix (such as e.g. the @0@ used by the end-user in Germany when dialling a number like @03012343038@ where @30@ is the Berlin Area code.  The correct representation of a German national number with Berlin prefix is @3012343038@, *without* the trailing zero)

h3. International

The _International_ type of number indicator is used to specify that the digits are in fully-qualified international format, including any international prefix such as @49@ for Germany.  The above-mentioned national number hence would be @493012343038@ in international type.

h3. Subscriber

The _Subscriber_ number

h3. Unknown

This _Unknown_ type of number indicator is used if the type is unknonw to the sender.  This basically makes the interpretation of the dialled digits dependent on the context/location/position in the network

h2. OCTOI specific references

You can find some related discussion on #6306 as well as [[DIVF_Dialplan]]