Results of the OTN interworking tests

Spring VON 2001

 

       1.         General

 

The current document is a summary report of the inter-working tests carried out  by Gallery IP Telephony, as part of the OTN program which took place in parallel to the Voice over the Network (VON) event at Phoenix, Arizona, during the dates March , 21th to 23rd , 2001.

 

The intent of the inter-working tests were to inter-work with different vendors of equipment and have the chance to commonly find the small glitches and failures which could appear in the messaging and interoperation due to different interpretations of specifications.

 

Gallery IP Telephony has brought to the test program its Softswitch which has the capabilities of :

 

I.        Call Agent – Capable to work with Residential Gateways and direct IP Telephones in the following protocols :

 

                                  ·          MGCP/NCS

                                  ·          SIP

 

The Call Agent allows the establishment of telephone calls between the POTS telephones connected to the Residential Gateway, based on the user dialing input. The Gallery IP Telephony Call Agent is actually the next generation Class 5 switch replacement for legacy switches. In addition to the proper connections, it allows the establishment of innumerous subscriber features , in a similar way to the one that exists at legacy Calss 5 switches and more.

 

II.     Media Gateway Controller (MGC) – Capable of controlling different types of Media Gateway equipment, following the MGCP protocol. The MGC component complements the capabilities of the Call Agent to allow calls that dial a destination outside the switch, to seize an outgoing trunk and route the call accordingly. The MGC capabilities allow also the receipt of incoming calls from the PSTN and their proper routing to the destination subscriber over a Residential Gateway.

 

III.   Signaling Gateway (SG) – Capable to communicate with SS7 to the PSTN. The SG allows the messaging between the Class 5 replacement softswitch with the exterior environment of the PSTN. The SS7 link may terminate in another switch (in case of associated signaling) but in most of the cases they terminate in an STP that transport the signaling content to its destination point code.

 

 

       2.         Testing content

 

      2.1.         General

 

The tests carried by Gallery IP Telephony during the OTN event can be divided in the following types of equipment:

 

·        CISCO UBR-924 Residential Gateway

 

·        NUERA – Trunk Gateway

 

 

      2.2.         CISCO UBR-924

 

The tests carried can be titled under the following categories:

 

  1. Verification of behavior of messages and of protocol:

 

        ·          Restart In Progress Message – Verification of receipt of the RSIP message upon the turning power on at the Residential Gateway.

        ·          Audit Endpoint Message – Verification that the Call Agent upon recognition of an RSIP message , acknowledges it by a Respond message followed by an Audit Endpoint message that queries the characteristics of the Residential Gateway to prepare the grounds for the processing of call establishment further on.

        ·          Request Notify – Verification that the Call Agent prepares the Residential Gateway for call initiation by sending it a RequestNotify message with the list of the events that are to be detected and a list of signals to supply to the line once an event occurs. Different Digit maps were verified to check the capability of the Residential Gateway to work in different dialing scenarios.

        ·          Notify – Verification that the Residential Gateway reports the occurrence of events as requested from it (By the RequestNotify message) .

        ·          CreateConnection – Verification that the Residential Gateway creates a connection from the analog subscriber side to the IP cloud side and properly sample and code the analog information and send it as packets to the determined port destination. Verification as well that the incoming packets are properly decoded and transposed to analog signals toward the subscriber analog interface. All these actions were verified to follow the command of the Call Agent as to the parameters to be chosen for the call creation.

        ·          ModifyConnection – Verification that the Residential Gateway follows the commands of the Call Agent as to the modification of the call mode and other parameters associated to the call establishment.

        ·          DeleteConnection – Verification that the Residential Gateway follows the commands of the Call Agent to tear down a connection, previously established and collecting statistical information as for the amount of packets transmitted, received and faulty on the connection.

 

All those message behavior verifications were executed and tested for compliance to the expected results.

 

 

 

 

  1. Verification of Call Flow

 

The following scenarios of Call Flow were executed and the messages sent between the Call Agent and the Residential Media Gateway were monitored and verified for correctness of “Grammar”.

 

The scenarios were executed by off-hook a telephone connected to a Residential Gateway A and calling the number that corresponds to a telephone connected to a Residential Gateway B.

 

        ·          Off-hook and On-hook

        ·          Off-hook , single digit dial and first digit time-out

        ·          Off-hook, digit series dial and inter-digit time-out

        ·          Off-hook, full digit series dial , ringing and on-hook before answer.

        ·          Off-hook, full digit series dial, ringing and answer.

        ·          Clear forward, Reorder tone and Release.

        ·          Clear Back, Reanswer, Clear Back and wait if regret time-out before disconnection.

        ·          Clear Back, Reanswer, Clear Back, Reanswer, Clear Forward, Reorder tone.

 

All those Call Flows were executed and tested for compliance to the expected results.

 

 

 

        2.3.          Nuera Trunk Gateway

 

  1. General

 

The inter-working test of the Nuera Trunk Gateway with the Gallery IP Telephony Ltd. Call Agent took place at the March 23rd which was the last day of the OTN tests and unfortunately it could not be fully completed due to lack of time.

 

It was agreed between Nuera and Gallery IP Telephony to continue the execution of compatibility tests between the two equipments during the following weeks.

 

The following are the tests that were successfully carried. A report will be sent to the Pulver organization to report further developments in the inter-working tests in front of the Nuera Trunk Gateways.

 

  1. Tests carried

 

The first test was to verify that the Call Agent receives the RSIP message sent by the Trunk Gateway upon powering up. The message was received properly and the Call Agent sent a “Respond” message followed by an AuditConnection command to learn more about the Trunk Gateway characteristics.

 

The Trunk Gateway sends as a response to the AuditEndpoint message the characteristics of its EndPoints and makes itself ready to receive the RequestNotify message from the Call Agent.

 

The MGC prepares the Trunk Gateway for the reception of events by providing it with the RequestNotify command with the relevant events requested to be reported, as well as the command to supply tones to the PSTN interface upon call start.

 

The Nuera Trunk Gateway started to report its receipt of an Off-hook (seizure)  from the CAS trunk side. For some unknown reason we could not respond to this message and the tests were stopped, mainly because lack of time to debug the situation and the inter-working behavior.

 

We have agreed between Nuera and us that we will continue the tests from the point we have stopped through the internet. It was agreed that both of us are going to report to the Pulver organization about the advance of those tests.