Patent Grant
7328271
The present invention relates generally to Internet Protocol (IP) telephony, and more particularly to a method of controlling IP telephones within a LAN-implemented or Ethernet PBX using a specialized messaging protocol.
With the increasing pervasiveness of the Internet, Voice-over-IP (VoIP) is rapidly displacing traditional TDM (Time Division Multiplexing) voice communications. In order to establish communications with Ethernet PBXs, an IP transport control messaging protocol is required to be established between the phone and PBX system.
According to the present invention, a method of controlling telephone connections for internet protocol communications comprises providing a byte oriented and easily adaptable messaging protocol for wrapping communications between IP telephones and Ethernet voice-LAN systems. The messages are required to implement essential tasks such as IP phone registration with the system upon phone power up or reset, the application of device tones to IP phones, and connection control for establishing full-duplex voice paths between IP phones. The messaging protocol of the invention also supports additional administrative and telephony functions.
The messaging protocol for wrapping the messages utilizes a general message template having a Protocol Header and an IP Message body. The Protocol Header, in turn, includes an indication of the Protocol Type, Device Number and Message Type. The Device Number identifies the entity sharing the same MAC (Media Access Control) address that the messages are destined to or coming from. Message Type identifies the type of message contained in the IP Message Body. The Protocol Type denotes whether the message is an IP message (e.g. Mitel proprietary Minet IP message) or an encapsulated non-IP message (e.g. Mitel proprietary Minet (MTS 22) message). The Minet (MTS 22) messaging protocol is implemented in Mitel PBX models SX50, SX200, SX2000, IPERA 2000 for communicating with associated telephones such as Mitel models SS4001, SS4015, SS4025, SS4150, SS4015IP and SS4025IP.
A preferred embodiment of the present invention will now be described more fully with reference to the accompanying drawings in which:
The method of controlling telephone connections for internet protocol communications using the messaging protocol which encapsulate a collection of specific messages of the present invention have particular application to the assignee's legacy mix of assembly and higher level languages. Consequently, reference to Minet and MinetIP messages occur throughout this disclosure to indicate the preferred embodiment and best mode implementation of the invention.
The Minet messaging extensions are structure based and are long word aligned, the result of which is that a user with a packet Sniffer will detect filler bytes in between short and long words.
In order to control a Mitel IP Phone, both Minet and Minet IP messages are required. A common message wrapper is defined to house the messages. The general message template consist of a Protocol Header and a Minet IP Message body that may or may not consist of an MTS22 Minet payload “wrapper”.
Protocol Header:
The message body follows the Protocol Header as shown in the structure below:
Protocol Type:
The Protocol Type denotes whether the message is a Minet IP message or an encapsulated Minet (MTS 22) message.
Device Number:
The Device Number denotes which entity shares the same MAC address with the entity the messages are destined to or coming from.
Message Type:
The above referenced message protocol is used to wrap or encapsulate each message sent and/or received by the IP phone or PBX. The following are examples of the use of the message protocol in reference to specific messages sent between IP telephones and Ethernet voice-LAN PBX systems. Each example begins by listing the Protocol header, Device Number and Message type.
Minet IP Registration Sequence
As shown in
The following messages are generated and exchanged between the IP phone and the PBX to register and de-register the phone 1 with the PBX 3:
Device Registration Request Message Sent from the IP Phone
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_REGISTRATION
DEVICE_REGISTRATION_MSG
Device Registration Request Acknowledgment Message Sent from System
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_REGISTRATION_ACK
DEVICE_REGISTRATION_ACK_MSG
Device De-Registration Request Message Sent from IP Phone.
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_DEREGISTRATION
Note that the IP Phone will not unregister itself, but rather an associated device such as a PKM may be removed and hence deregistered.
DEVICE_UNREGISTER_MSG
Device De-Registration Acknowledgment Message Sent from System
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_DEREGISTRATION_ACK
DEVICE_UNREGISTER_ACK_MSG
Detailed Description of Registration Parameters
devType:
devNumbers:
MASTER_DEVICE 0x00000000
Where Set=0, and any attached devices will be numbered MASTER_DEVICE+n where n>=1
reqStatus (Success/failure codes):
devCodecs bitmap:
For system maintenance purposes, it is desirable to provide a mechanism for testing the presence of an operating IP phone 1 in the system by generation of echo (PING) messages to the phone 1. The following messages are generated and exchanged between the IP phone and the PBX to implement this functionality:
Device ICMP Echo (Ping) Request to the Phone
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgtype=DEVICE_PING
DEVICE_PING_REQUEST_MSG
Device ICMP Echo (Ping) Results Sent from the Phone to the System
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_PING_ACK
DEVICE_PING_ACK_MSG
Detailed Description of PING Parameters
qosLevel:
Once the IP phone 1 has been registered with PBX 3, and in response to a user going off-hook, the PBX 3 is required to provide tones to the phone in order to provide the user with an indication of the call state (e.g. dial tone, busy, etc.) The following messages are generated and exchanged between the IP phone and the PBX for providing device tones to the phone 1:
Apply Tone Device Tone Generation Request Message to the Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=APPLY_TONE
Remove Tone Device Tone Generation Request Message to the Phone
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=REMOVE_TONE
REMOVE_TONE_REQUEST_MSG
Detailed Description of TONE Parameters
inject:
Open Receive Stream Request to the Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=OPEN_RX_STREAM
Open Receive Stream Acknowledgement from the IP Phone to the System:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=OPEN_RX_STREAM_ACK
OPEN_RX_STREAM_ACK_MSG
Close Receive Stream Request from the System to the IP Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=CLOSE_RX_STREAM
CLOSE_RX_STREAM_REQUEST_MSG
Close Receive Stream Acknowledgement from the IP Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=CLOSE_RX_STREAM_ACK
CLOSE_RX_STREAM_ACK_MSG
Open Transmit Stream Request to the IP Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=OPEN_TX_STREAM
OPEN_TX_STREAM_REQUEST_MSG
Open Transmit Stream Acknowledgement from the IP Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=OPEN_TX_STREAM_ACK
OPEN_TX_STREAM_ACK_MSG
Close Transmit Stream Request to the IP Phone
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=CLOSE_TX_STREAM
CLOSE_TX_STREAM_REQUEST_MSG
Close Transmit Stream Acknowledgement from the IP Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=CLOSE_TX_STREAM_ACK
CLOSE_TX_STREAM_ACK_MSG
Detailed Description of Connection Parameters
reqStatus (Success/failure codes):
SysStrmID:
IP Set Stream IDs: (NOTE: TX is always even) used for sysStrmID of TX & Rx connect requests
devCodecs bitmap:
qosLevel:
One important system administration requirement for IP phone systems is to provide a mechanism for updating the IP address for a device (e.g. an IP phone) connected to the Ethernet PBX 3. The following messages are generated and exchanged between the IP phone and the PBX to implement this functionality:
Device IP Address Update Request to the Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_IP_UPDATE
DEVICE_IP_UPDATE_REQUEST_MSG
Device IP Address Update Acknowledgement from the Phone:
ProtoType=MITEL_INTERNAL
DevNum=N where N=0, 1, 2, . . . n
msgType=DEVICE_IP_UPDATE_ACK
DEVICE_IP_UPDATE_ACK_MSG
devNumbers:
MASTER_DEVICE 0x00000000
Where Set=0, and any attached devices will be numbered MASTER_DEVICE+n where n>=1
Finally, as indicated above, the messaging protocol of the present invention allows for the encapsulation of “legacy” Minet messages (i.e. MTS 22 messages) to and from the IP phones. The following message format is used:
Wrapper Structure for MINET Messages to and from the IP Phone:
ProtoType=MINET_MTS22
DevNum=N where N=0, 1, 2, . . . n
msgType=MINET_WRAPPER
MINET_WRAPPER_MSG
Parameters Description
MAX_MINET_SIZE 160
In summary, according to the present invention, a method of controlling telephone connections for internet protocol communications comprises providing a messaging protocol for wrapping or encapsulating messages exchanged between an IP phone and a PBX, the message protocol using a general message template having a Protocol Header and an IP Message body, along with a collection of messages which conform to the protocol, for controlling IP phones within an Ethernet-based PBX system. The invention has particular applicability as a message interface method for use in communication from Mitel's IP Phones to Mitel's IP enabled PBXs. The message interface method is compatible with an H323 Voice Gateway implementation.
Alternatives and variations of the invention are possible. For example, the protocol can be adapted to control voice/data switching on any IP centric node. In other words, the protocol is not constrained to phones but, rather, can be applied to any internet appliance that is a client to the IP centric PBX. Within the PBX, the protocol can be used by call control in order to control the switching fabric. All such embodiments, modifications and applications are believed to be within the sphere and scope of the invention as defined by the claims appended hereto.
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| Number | Date | Country | |
|---|---|---|---|
| 20020174240 A1 | Nov 2002 | US |
