Saturday, 2 May 2015

'+' Sign Call Routing


+ Sign Concept

ITU defined E164 as the standard for 'Numbering Plan of the International Telephone Service' which is in the format

CC + NDC + SN: Maximum of 15 digits

  • CC : Country code, 1 – 3 digits
  • NDC: National destination code
  • SN: Subscriber number

ITU defined E123 as the standard for 'Notation for national and international telephone numbers, email addresses and web addresses'

Telephone number, national notation: (042) 1123 4567
Telephone number, E.123 international notation: +31 42 1123 4567

Accordingly it is recommended to store numbers in global directories in +E.164 format:

  • Global form including country code
  • Leading “+”
  • No trunk access codes included: +44 (0) 208 1234 1243 is NOT a valid +E.164 number.

From a dial plan perspective, supporting the + sign allows UCM-based systems to route calls based on an universal non-site (country) specific format.

+E.164 support includes the use of + to wildcard international access codes AND to avoid overlap between globalized numbers and other ranges (e.g.: calls to India (+91XXXXXXXXX) and NANP toll calls (912125551234).

Note: CUCM needs '\' to be added to DNs starting with '+' sign (e.g. \+97145673459).

+ Sign Support

All IP Phones with the exception of 7940/60 already support "+" dialing from the missed calls directory (firmware version 9.1.1). Entering a "+" already is supported on Cisco Unified Personal Communicator and on the 7925 phone (press and hold 0). Support for other phone models is planned. If E.164 dialing is a requirement Cisco currently recommend to use "*" as the steering character to initiate E.164 dialing. The "*" can be entered on all existing phone models. The dialplan in Cisco Unified Communications Manager has to be able to consume the *E.164 dialing.

Prior to version 8.0, CUC doesn't support +E164 DNs yet as you can't assigned +E164 number as voice mailbox extension. You need to use digit manipulation to mask '+' sign for incoming call and prefix '+' sign for outgoing calls/MWI. However starting from CUC 8.0,  +E164 support started for Alternate Extensions.

By default translation patterns applied to prefix digits for MWI DNs won't take effect unless "Multiple Tenant MWI Modes" service parameter is set to true. This parameter specifies whether to apply translation patterns to voice-message mailbox numbers.

Starting from CUC 9.0, +E164 full support was introduced. This can be used for

  • Primary extensions for the end user
  • Transfer extensions for the end user
  • Call Handler Extensions
  • Trap Calls
  • Notification device phone numbers for the end user
  • Personal contact phone numbers for the end user
  • Restriction patterns for the Connection system
  • Message Waiting Indicator extensions for the Connection System

Note: If the two users have same numeric extensions, one extension is with "+" character and another without "+" character, such entries are considered as duplicate entries. For example, +1 408 526 4000 and 1 408 526 4000 are treated as one extension only in the same partition. The users can login with or without "+" as a prefix into their voice mailbox over TUI.
 

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