SIP Number Normalization
This section explains the SIP number normalization feature that applies to the SIP To URI. (Currently the Oracle® Enterprise Session Border Controller supports number normalization on From and To addresses for both inbound and outbound call legs.) Number normalization includes add, delete, and replace string functions that result in consistent number formats.
Number normalization is supported for the following call types:
- SIP to SIP
- H.323 to SIP
Number normalization applies to the SIP To URI. It occurs on ingress traffic, prior to the generation of accounting records or local policy lookups. RADIUS CDR attributes are populated with the normalized numbers. Local policy matching is based on the normalized numbers.
Terminology
The following lists explains the terminology used later.
- X is any digit having the value 0 through 9
- N is any digit having the value 2 through 9
- 0/1 is a digit having the value of either 0 or 1
- NXX is a form of Numbering Plan Area (NPA).
- CC is a 1, 2, or 3 digit country code used in international dialing
- NN is a national number that can be a four to fourteen digit national number used in international dialing, where the combination of CC+NN is a 7 to 15 digit number.
- + symbol in E.164 indicates that an international prefix is required
- E.164 numbers are globally unique, language independent identifiers for resources on Public Telecommunication Networks that can support many different services and protocols.
- N11 number is any of the three-digit dialing codes in the form N11 used to connect users to special services, where N is a digit between 2 and 9
Calls from IP Endpoints
The Oracle® Enterprise Session Border Controller uses the following number normalization rules:
- North American Numbering Plan (NANP) calls: where a number with the format 1NPANXXXXXX is received, the
Oracle® Enterprise Session Border Controller adds a plus sign (+) as a prefix to the NANP number. The
Oracle® Enterprise Session Border Controller also adds the string ;user=phone after the host IP address in the SIP URI. For example:
sip:+1NPANXXXXXX@ipaddr;user=phone
- International NWZ1 calls:
Oracle® Enterprise Session Border Controller receives an international call with the format 011CCNN. The
Oracle® Enterprise Session Border Controller deletes the 011 prefix and adds a plus sign (+) as a prefix to CC+NN; and also adds the string ;user=phone after the host IP address in the SIP URI. For example:
sip:+CCNN@ipaddr;user=phone
- Private number calls: when a private number with the format nxxxx (where n=2 through 9) is received, no number normalization is applied by the Oracle® Enterprise Session Border Controller.
- Calls to numbers such as N11, 0-, 0+, 00-, and 01+: the
Oracle® Enterprise Session Border Controller adds ;phone-context=+1 after the number and also adds the string ;user=phone after the host IP address in the SIP URI. For example:
sip:N11;phone-context=+1@ipaddr;user=phone sip:01CCNN;phone-context=+1@ipaddr;user=phone
- Calls with numbers that are already normalized are not modified by the Oracle® Enterprise Session Border Controller.
Calls from IP Peer Network
For calls received from external peer networks, the Oracle® Enterprise Session Border Controller uses the following number normalization rules:
- Global numbers such as NANP and international E.164 numbers should have already been normalized. If not, the Oracle® Enterprise Session Border Controller applies the same number normalization rules listed in the prior section.
- Calls to numbers such as N11, 0-, 0+, 00-, and 01+: the Oracle® Enterprise Session Border Controller adds ;phone-context=+1 after the number and also adds the string ;user=phone (if absent) after the host IP address in the SIP URI.
