INdigital ESinet SIP interconnection

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last edit: 25 September 2013 17:03

Version 1.9 (13-268.4)

INdigital ESinet

SIP interconnection

a whitepaper guide to sip trunk

connections for INdigital ESinets

issued as a part of the INdigital telecom

‘network notes’ series

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2 of 10 content and concepts © INdigital telecom

Overview:

This paper describes the various options a 911 originating service provider (911 OSP) can use to establish SIP trunk based connections to NENA i3 structured Emergency Services Internetworks (ESinet) designed, installed or operated by INdigital telecom. SIP interconnection allows OSP’s to deliver 911 calls for service to the ESinet, which will then result in the call being routed to the appropriate public safety answering point (PSAP).

INdigital’s ESinet architecture is based on the RFC-3261 standard, generally available at the IETF website: http://tools.ietf.org/wg/sip/

INdigital also supports the additional industry protocols:

RFC-3262; RFC-3264; RFC-3311; RFC-3323; RFC-3325; RFC-3326; RFC-3398; RFC-3515; RFC-3525; RFC-3761; RFC-3824; RFC-3891; RFC-4028; RFC-4317; RFC-4488; RFC-4566; and RFC-4694.

If the need arises to support services and protocols such as the 183 call signaling sub-protocol (early media or provisional ACKs,) these specifics can be negotiated per interconnect development, and a suitable technology bridge will be proposed and developed to meet individual needs.

1) SIP Interconnection specifics:

A). Transport Facilities: INdigital ESinets generally support access to multiple

different transport providers. Full interconnection to many multicarrier facilities, E-line/E-LAN, P2P, MPLS or VPN are just a few of the connection options available. A list of interconnection locations is available to our business partners, depending on the ESinet where connection is required.

Development Environments, Pre-production Staging Environments:

Secure IP tunnels over commodity internet connections are fully supported, and are often used for development and pre-production testing.

Production Environment: INdigital recommends a dedicated, private

connection arrangement. The service provider’s transport facility can terminate to any of INdigital’s POP locations. A list of these locations is available to our business partners.

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3 of 10 content and concepts © INdigital telecom  INdigital recommends the use of redundant and diverse transport

facility arrangements and redundant hardware where possible to maximize resiliency and eliminate any single point of failure.

 Industry standards recommend to two points of geo-diverse private connections with an internet based VPN backup.

 INdigital’s minimum requirement are one point of interconnection via private connection (T1-Data, Ethernet, MPLS, E-line/E-LAN.) The secondary or redundant connection can be an additional private connection or VPN via the public Internet.

B). Transport Protocol: The INdigital network currently supports IPv4

connections. IPv6 is not fully supported at this time due to the immaturity and slowly evolving industry support of the protocol.

C). SIP Termination: The INdigital network has multiple SIP Session Border

Controllers (SBC) available for SIP termination. SIP termination is, however, an inexact science, and the exact method used by an OSP will need to be engineered on a case by case basis, thereby fully defining the method of interconnection in this document will use broad, general terms.

D). ESinet / SBC Security Measures: INdigital requires that the OSP use some

form of SBC at their OSP network to transport platform handoff location. The SBC is primarily used for topology hiding, RTP proxy and normalization of the SIP protocol. If the interconnecting company cannot provide these SBC functions, INdigital can suggest a configuration that meets industry

standards and practices.

E). Call Signaling requirements: SIP call signaling will use 911 as the called

party number in cases where the ESN (emergency service number) is not already known, (i.e. for calls that are not pre-selective routed.)

The Calling Party Number (CPN); P-ANI/ESRK; or ANI can be used if the ESN of the Emergency Services Agency is known. The ESN can also be signaled using INdigital’s ESN number as the called party.

Currently, only Called and Calling party fields are used for selective routing within the ESinetwork. Deviation from these configurations are negotiated on a per interconnection specific basis.

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F). Geo-Routing: For information regarding the ability to geo-route calls

using PIDF-lo body or header fields, contact INdigital for an expanded discussion of this service feature. This mode of operation is defined in RFC-2778 and RFC-4119. These configurations can be negotiated on a per interconnection basis.

2) INdigital SIP profile:

SIP methods supported ACK, BYE, CANCEL, INVITE, OPTIONS (required)

SIP timer values used T1 500ms; T2 4sec; T4 5 sec SIP OPTIONS (pings) supported? Yes

Support/require PRACK? No

SBC Vendor/Model/Software Version ACME Packet Net-Net or Similar

Support/require Early Media? Egress CPE/Gateway dependent

Calling Party one of the following:

From: P-Asserted-ID:, Remote-Party-ID:

Caller DN or ESRK of calling party preferred

Called Party (To:) Agreed upon per connection

RTCP Optional

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3) INdigital Media Profile:

Supported codecs G.711u

Sampling rate 20ms

UDP/TCP UDP (unless otherwise agreed)

Port Signaling 5060

RTP port range 10000-29999

Support transcoding of media? No

RTCP enabled? This is user agent specific. Certain CPE/Gateways associated with ESinets will support it, but not all. Expected network delay for RTP Internally <40ms. However, we

often deploy large scale ESinets using multiple transport types.

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4) SIP Message Example

A). INdigital can provide message examples upon request. B). Functional block diagram

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INdigital contacts

Parties needing additional information about INdigital ESinet SIP trunking or other general inquiries regarding NG9-1-1 or E9-1-1 trunking are invited to write or call:

Brent Cummings, Director of Operations bcummings(at) indigital.net

or

Kent Claussen, Chief Technical Officer kclaussen(at) indigital.net

or

Bobbie Carter, Project Manager bcarter(at) indigital.net

INdigital Telecom 1616 Directors Row Fort Wayne IN 46808

Phone toll free: 877-469-2010

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Glossary of Terms

ANI: Automatic Number Identification, describes the actual telephone number of a calling party.

CPE: Customer Premises Equipment

DTMF: Dual-tone multi-frequency signaling

ESN: Emergency Service Number, a numerical identification for a specific emergency service provider. In this case used to assist in routing Emergency Calls for Service.

ESRK: Emergency Service Routing Key. This generally describes a non-dialable telephone number used as a record reference number for looking up caller location information for wireless, or similar nomadic type calls, for emergency services. See also P-ANI

Gateway: An entrance point from one network to another

G.711u: The default modulation scheme for Internet Protocol (IP) private branch exchange (PBX) vendors. G.711 digitizes analog voice signals. IETF: Internet Engineering Task Force. A standards setting body for the

development and adoption of recommended standards defining IP and SIP protocols (among others.)

INdigital Emergency Service Internetwork (ESinet): A private IPv4 voice and data network owned and operated by INdigital telecom. The network can receive, selectively route and deliver 9-1-1 telephone calls (public to authority) to emergency communications centers using VoIP

technology.

IP: Internet Protocol. Also referred to as IPv4 in this white paper to specify that the network operates using Internet Protocol version 4. P-ANI: Pseudo Automatic Number Identification. See also ESRK

PIDF-LO: Presence Information Data Format Location Object. (See also RFC 2778 and RFC 4119)

POP: Point of Presence

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9 of 10 content and concepts © INdigital telecom RFC: Request For Comments – a distributed method of the development of

standards used by the IETF. RTP: Realtime Transport Protocol RTCP: RTP Control Protocol

SBC: Session Border Controller, is a network element used in VoIP

networks to exert control over the signaling (and usually the media streams) involved in setting up, conducting, and tearing down telephone calls or other interactive media communications. SIP: Session Initiated Protocol

T-1: A digital transmission link with a signaling speed of 1.544 Mbps. UA: User Agent

UBE: Unified Border Element VoIP: Voice over Internet Protocol

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Appendix A

This appendix contains the physical address and NPA-NXX of the ESinet SIP gateways. This appendix is for preliminary planning purposes only.

The information needed to place orders for interconnection will be provided upon successful validation of the Carriers ability to meet the requirements of the ESinet users for security, interconnection, and stability.

The information contained in this appendix is

Private and Confidential

INdigital telecom 1616 Directors Row Fort Wayne, IN 46808 877-469-2010

574-595