GR-303 - Revision history

Luc Morissette: /* Configuration */

2025-11-28T19:29:25Z

Configuration

← Older revision		Revision as of 15:29, 28 November 2025
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	= Configuration =		= Configuration =
	[[Media:Gr303_Basic_configuration.pdf\|GR303 SIP configuration manual]]		* [[Media:Gr303_Basic_configuration.pdf\|GR303 SIP configuration manual]]
	[[Media:TelcoBridges_GR303_H248_Configuration.pdf\|GR303 H.248 configuration manual]]		* [[Media:TelcoBridges_GR303_H248_Configuration.pdf\|GR303 H.248 configuration manual]]

Luc Morissette: /* GR-303 Overview in H.248 Architecture */

2025-11-28T19:29:08Z

GR-303 Overview in H.248 Architecture

← Older revision		Revision as of 15:29, 28 November 2025
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	---		---

			== Summary ==

	The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for telecom networks, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.		The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for telecom networks, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.

Luc Morissette: Added links to configuration manuals

2025-11-28T19:28:38Z

Added links to configuration manuals

← Older revision		Revision as of 15:28, 28 November 2025
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	---		---

	~~= In Summary =~~

	The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for telecom networks, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.		The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for telecom networks, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.

			= Configuration =
			[[Media:Gr303_Basic_configuration.pdf\|GR303 SIP configuration manual]]
			[[Media:TelcoBridges_GR303_H248_Configuration.pdf\|GR303 H.248 configuration manual]]

Luc Morissette: Summary

2025-11-28T19:21:46Z

Summary

← Older revision		Revision as of 15:21, 28 November 2025
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	---		---

	= ~~Conclusion~~ =		= In Summary =

	The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for ~~modern softswitch architectures~~, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.		The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for telecom networks, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.

Luc Morissette at 19:21, 28 November 2025

2025-11-28T19:21:02Z

← Older revision		Revision as of 15:21, 28 November 2025
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	* The IDT maps those channels to either:		* The IDT maps those channels to either:

	* '''H.248 terminations'''		** '''H.248 terminations'''
	* '''SIP subscriber endpoints'''		** '''SIP subscriber endpoints'''

	== Key Objectives ==		== Key Objectives ==

Luc Morissette: New GR303 page

2025-11-28T19:20:30Z

New GR303 page

New page

= Introduction =

The '''GR-303 interface''', originally defined by Telcordia, provides a digital interface between a '''Remote Digital Terminal (RDT)''' and a '''Central Office switch''' using T1-based bearer and signaling channels.
In TelcoBridges implementations, the device operates as an '''Integrated Digital Terminal (IDT)''', providing the switch-side termination of GR-303.

GR-303 enables:

* Concentration of analog subscriber loops
* Digital transport over T1
* Logical grouping of subscriber channels into IDT groups
* Separation of signaling and bearer channels
* Scalability across thousands of lines

Since '''Toolpack/Tmedia v3.3''', TelcoBridges platforms support full GR-303 IDT functionality on '''Tmedia''' appliances.

---

= Overview =

GR-303 separates the interface into three logical components:

* '''TMC (Time Slot Management Channel)''' — bearer channel mapping
* '''EOC (Embedded Operations Channel)''' — OAM & control
* '''Channel Associated Signaling (CAS)''' — subscriber line state signaling

In a TelcoBridges solution:

* The '''RDT''' provides the analog subscriber access.
* The '''IDT''' (the TelcoBridges device) terminates the RDT’s GR-303 CAS/T1 channels.
* The IDT maps those channels to either:

* '''H.248 terminations'''
* '''SIP subscriber endpoints'''

== Key Objectives ==

* Provide a scalable GR-303 digital switch interface
* Support a wide range of legacy RDT vendors
* Allow migration paths to SIP and VoIP architectures
* Ensure consistent signaling between CAS, H.248, and SIP

---

= Features and Capabilities =

== System Capabilities ==

* '''Up to 42 IDT groups''' per system
* '''Up to 28 T1s per group'''
* '''Primary/Backup TMC & EOC''' redundancy
* '''1+1 High Availability'''
* '''CAS loopstart''' signaling on GR-303 T1s
* Support for industry-standard RDT vendors
** Adtran TA5000
** Calix C7
** AFC
** Tellabs UMC1000
** Motorola/Arris AXS2200

---

= GR-303 Call Flow (Engineering Detail) =

== Call Routing ==

Routing differs:

=== SIP Mode ===

* Routing is determined by the TMG routing engine
* The subscriber is defined in a csv file (subscriber to GR303 crv value)

=== H.248 Mode ===

* Softswitch determines call flow
* IDT simply reports events and manages media terminations
* Full feature set is supported

---

= GR-303 Overview in SIP Architecture =

== SIP Architecture Diagram ==

GR303 RDT -- GR303 CAS/T1 -- TMG800 / TMG3200 IDT -- SIP + RTP -- Softswitch

== SIP Integration Details ==

* Each subscriber '''registers individually''' to the SIP registrar
* Each subscriber must have an entry in the '''CRV mapping CSV file'''
* CAS → SIP signaling translation is handled by the IDT

=== Supported SIP features ===

* Basic call
* SIP registration
* Single dial plan

---

= GR-303 Overview in H.248 Architecture =

== H.248 Architecture Diagram ==

GR303 RDT -- GR303 CAS/T1 -- TMG800 / TMG3200 IDT -- H.248 + CAS -- Softswitch (MGC)

== H.248 Integration Details ==

* IDT appears as a standard '''H.248 Media Gateway'''
* Subscriber loops appear as '''Terminations'''
* Softswitch has full control over:
** digit collection
** feature activation
** ring cadence
** call routing
** media negotiation

=== Supported features ===
* Caller ID
* Call waiting
* Call transfer
* 3-way conference
* ESA (Emergency Standalone), switch dependent

---

= Conclusion =

The TelcoBridges GR-303 implementation provides a robust, scalable, and flexible IDT-side interface suitable for modern softswitch architectures, enabling a seamless migration path from legacy TDM access lines to VoIP core networks via SIP or H.248.