This will demonstrate how you can add an Amazon Lex Bot to an existing contact center. In this example, an Amazon Chime Voice Connector will be used to deliver PSTN calls but any carrier can be used in your environment.
This demo will allow you to see how to add an Amazon Lex Bot to an existing contact center using Amazon Chime Voice Connectors. An Amazon Lex Bot can be used to enhance your contact center with deflection and intelligent routing through self service. In this demo, the information gathered By the Amazon Lex Bot is stored in an Amazon DynamoDB and then queried by the SBC/PBX to determine the next call routing action. Other options are also available if your SBC/PBX is not capable of this type of call routing. This data is also delivered to the Agent so that they are presented with the relevant information the caller gave to the Amazon Lex Bot. The Amazon Lex Bot included in the demo contains three Intents - Check Balance, Transfer Funds, and Open Account. If the caller chooses the Check Balance or Transfer Funds Intent by speaking one of the Utterances that trigger them, the Amazon Lex Bot will collection information from the caller. When completed, the caller will be disconnected. However, if the caller selects Open Account, the Amazon Lex bot will collection information from the caller and then will be connect the caller to an agent.
After deploying the CDK, a phone number and aws ssm command will be provided to you:
Outputs:
LexContactCenter.ssmCommand = aws ssm start-session --target i-0c61c739c02359f9f
LexContactCenter.voiceConnectorPhone = +1NPANXXXXXX
You can optionally use the aws ssm command to connect to the Asterisk server deployed as part of this demo. The voiceConnectorPhone provided is the number to dial to connect to the Amazon Lex bot through the Asterisk server. Dial that number from any PSTN based phone to test the demo.
The first portion of this call flow is a call from the PSTN. This call will be answered by an Asterisk PBX. In your environment this could be some combination of an SBC and Contact Center.
INVITE sip:+1NPANXXXXXX@54.225.191.168:5060;transport=UDP SIP/2.0 Via: SIP/2.0/UDP 3.80.16.132:5060;branch=z9hG4bK980f.18c7e855b3ca2c197661a8838c65c32d.0 From: < sip:+1NPANXXXXXX@10.0.127.102:5060 >;tag=4XU48Ua5NDrcr To: < sip:+1NPANXXXXXX@54.225.191.168:5060 >;transport=UDP X-VoiceConnector-ID: bxhrxku1lu5jcu0roa4ca7
This Asterisk will then route the call to an Amazon Chime Voice Connector via SIP. An extra header has been added that will be used to correlate the call through the different components.
INVITE sip:+18005551212@do7wjdbi641ffigpabxkfr.voiceconnector.chime.aws SIP/2.0 Via: SIP/2.0/UDP 54.225.191.168:5060;rport;branch=z9hG4bKPj3f8527cb-1f02-4721-9c5c-ec38479ed46b From: < sip:+1NPANXXXXXX@10.0.0.141 >;tag=d489c3f5-bebc-4785-afc9-a12f0ed7cf5a To: < sip:+18005551212@grrrp7d8qefmxe2jww7qb8.voiceconnector.chime.aws > X-CallId: 56983520
In this example SIP INVITE from the Asterisk to the Amazon Chime Voice Connector, the original-calling-number is passed as the FROM number and a new number is used as the TO number. This number does not need to be a number in your Amazon Chime Phone Inventory. The X-CallId is added as a unique identifier for correlation purposes.
To deliver the call to the PSTN Audio via SIP, the call is sent to Amazon Chime Voice Connector. This Amazon Chime Voice Connector is configured as the Trigger Value for the SIP Rule.
This SIP Rule targets a SIP media application that is associated with an AWS Lambda that will be triggered when a call is made to that Amazon Chime Voice Connector. This is how a SIP call can be made from an existing Contact Center to an Amazon Chime PSTN Audio SIP media application.
The SIP media application handler Lambda will be invoked with an event similar to this:
{
"SchemaVersion": "1.0",
"Sequence": 1,
"InvocationEventType": "NEW_INBOUND_CALL",
"CallDetails": {
"TransactionId": "23fe0cf1-fc36-4bdc-976d-3520c0a3ac86",
"AwsAccountId": "111122223333 ",
"AwsRegion": "us-east-1",
"SipRuleId": "3f5f6ec1-6004-494a-b514-1673d62cb8c5",
"SipMediaApplicationId": "8a912ad2-67aa-4852-a892-34a454d370c7",
"Participants": [
{
"CallId": "f06dd26d-fcaf-411e-9cdb-05ac726e1b9a",
"ParticipantTag": "LEG-A",
"To": "+18005551212",
"From": "+1NPANXXXXXX",
"Direction": "Inbound",
"StartTimeInMilliseconds": "1648477951790",
"SipHeaders": {
"X-CallId": "56983520"
}
}
]
}
}This invocation is a NEW_INBOUND_CALL that contains the same X-CallId information that was sent to the Amazon Chime Voice Connector and will be used to store information in an Amazon DynamoDB table. Once the data has been stored, the Lambda will return a StartBotConversation action to the SIP media application.
exports.handler = async (event, context, callback) => {
let actions;
switch (event.InvocationEventType) {
case 'NEW_INBOUND_CALL':
console.log('NEW INBOUND CALL');
await putInfo(event);
startBotConversationAction.Parameters.Configuration.SessionState.SessionAttributes.phoneNumber =
event.CallDetails.Participants[0].From;
actions = [startBotConversationAction];
break;The resulting startBotConversationAction sent to the SIP media application will look something like this:
{
"SchemaVersion": "1.0",
"Actions": [
{
"Type": "StartBotConversation",
"Parameters": {
"BotAliasArn": "arn:aws:lex:us-east-1:111111111111:bot-alias/MJBJRG3FRF/TSTALIASID",
"LocaleId": "en_US",
"Configuration": {
"SessionState": {
"SessionAttributes": {
"phoneNumber": "+1NPANXXXXXX"
},
"DialogAction": {
"Type": "ElicitIntent"
}
},
"WelcomeMessages": [
{
"ContentType": "PlainText",
"Content": "How can I help you today? You can check your account balances, transfer funds, or open a new account.."
}
]
}
}
}
]
}
This will begin the conversation between the caller on the PSTN and the Amazon Lex Bot. Additionally, it will pass the caller's phone number to the Amazon Lex Bot as a Session Attribute. This will be used later as part of the Open Account Intent.
Within the Amazon Lex Bot, one of three Intents can be invoked using different Utterances. To invoke the Check Balance Intent, speak one of the sample Utterances:
Each Intent has different Utterances that will trigger the Intent. The Check Balance Intent will invoke an attached Lambda that will generate simuated data and respond to the caller with that data as part of the Fullfillment. Similarly, the Transfer Funds Intent will collect information from the caller from several Slots before completing.
These Slots can be collected at once with an Utterance like I'd like to transfer 100 from Checking to Savings or collected indivually in response to messages from each Slot:
Amazon Lex: Which account would you like to transfer from?
Caller: Checking
The Open Account Intent uses turn by turn code hooks to validate and confirm the responses from the caller with an AWS Lambda. Additionally, this Intent uses information collected from the Amazon Chime PSTN Audio to automatically populate a Slot. In this example, the phoneNumber slot uses the default value of the [phoneNumber] Session Attribute that was passed to the Amazon Lex Bot from the Amazon Chime PSTN Audio SIP media application. Once Confirmed and Fullfilled, this information will be returned to the Amazon Chime PSTN Audio handler to be stored and later used.
Once the conversation with the Amazon Lex Bot has completed, it will invoke the SIP media application Lambda with the full results of the Amazon Lex Bot conversation. Below is a trimmed example showing an ACTION_SUCCESSFUL invocation after a StartBotConversation action when the OpenAccount Intent was used.
{
"SchemaVersion": "1.0",
"Sequence": 2,
"InvocationEventType": "ACTION_SUCCESSFUL",
"ActionData": {
"IntentResult": {
"Interpretations": [
{
"NluConfidence": {
"Score": 1
},
"Intent": {
"Name": "OpenAccount",
"Slots": {
"firstName": {
"Value": {
"OriginalValue": "john",
"InterpretedValue": "john",
"ResolvedValues": []
},
"Values": []
},
"lastName": {
"Value": {
"OriginalValue": "dou",
"InterpretedValue": "dou",
"ResolvedValues": []
},
"Values": []
},
"phoneNumber": {
"Value": {
"OriginalValue": "",
"InterpretedValue": "1NPANXXXXXX",
"ResolvedValues": ["1NPANXXXXXX"]
},
"Values": []
},
"accountType": {
"Value": {
"OriginalValue": "checking",
"InterpretedValue": "Checking",
"ResolvedValues": ["Checking"]
},
"Values": []
}
},
"State": "Fulfilled",
"ConfirmationState": "Confirmed"
}
}
]
},
"Type": "StartBotConversation"
},
"CallDetails": {
"TransactionId": "23fe0cf1-fc36-4bdc-976d-3520c0a3ac86",
"AwsAccountId": "104621577074",
"AwsRegion": "us-east-1",
"SipRuleId": "3f5f6ec1-6004-494a-b514-1673d62cb8c5",
"SipMediaApplicationId": "8a912ad2-67aa-4852-a892-34a454d370c7",
"Participants": [
{
"CallId": "f06dd26d-fcaf-411e-9cdb-05ac726e1b9a",
"ParticipantTag": "LEG-A",
"To": "+18005551212",
"From": "+1NPANXXXXXX",
"Direction": "Inbound",
"StartTimeInMilliseconds": "1648749429539",
"Status": "Connected",
"SipHeaders": {
"X-CallId": "56983520"
}
}
]
}
}When this ACTION_SUCCESSFUL is received the Lambda handler will perform the following actions:
- Parse results
- Determine next call route action
- Store results in DyanmoDB table
- Return
hangupActionto SIP media application
exports.handler = async (event, context, callback) => {
let actions;
switch (event.InvocationEventType) {
case 'ACTION_SUCCESSFUL':
console.log('ACTION SUCCESSFUL');
await parseResult(event);
actions = [hangupAction];
break;if (event.ActionData.IntentResult.SessionState.Intent.Name === 'OpenAccount') {
callRoute = 'CallAgent';
} else {
callRoute = 'Disconnect';
}The DynamoDB table will now look like this:
The hangupAction from the SIP media application returns the call to the Asterisk PBX. In this example, if the OpenAccount Intent is used, the call is sent to an Agent using a web client based SIP phone. This client will then query the DynamoDB table for the information captured from the Lex Bot. Your environment may have different devices and configurations. If the CheckBalance or TranferFunds intent is used, the Asterisk PBX will Hangup the call.
same => n,Set(CALL_ROUTE=${SHELL(curl --silent API_URLquery?xCallId=${CallId} | jq -r .CallRoute )})
same => n,NoOp(${CALL_ROUTE})
same => n,GotoIf($[${CALL_ROUTE} = CallAgent]?callAgent:disconnect)
The Intent that was used is determined by a query from the PBX to the DynamoDB where the call information was stored. In this example, if the caller used CheckBalance, that information would be stored in the DynamoDB by the smaHandler Lambda and the call would be disconnected. However, if the caller used TransferFunds, they would be connected to an Agent. This is an exmaple of how the Amazon Lex Bot can be used for deflection in the case of self-service and intelligent routing when required.
INVITE sip:rm68qs0l@173.25.202.6:50131;transport=ws SIP/2.0
Via: SIP/2.0/WS 10.0.0.141:8088;rport;branch=z9hG4bKPjb2c966b1-bb9b-4951-982f-cdd820518f71;alias
From: <sip:+1NPANXXXXXX@ip-10-0-0-141.ec2.internal>;tag=e8a6c3dc-1c02-432c-8dc9-9c335867d4d9
To: <sip:rm68qs0l@173.25.202.6>
X-CallId: 56983520
When answered, the client will display the results of the query to the DynamoDB table that contains the information the caller gave to the Amazon Lex Bot.
async function dataDipByXCallId(xCallId) {
const queryResponse = await API.get('queryAPI', 'query', {
queryStringParameters: {
xCallId: xCallId,
},
});
const completeResults = {
ConfirmationState: queryResponse.ConfirmationState,
CallingNumber: queryResponse.CallingNumber,
};
for (const [key, value] of Object.entries(queryResponse.LexResults)) {
completeResults[key] = value;
}
setLexResults(completeResults);
}- Amazon Chime Voice Connector - PSTN Access w/DID
- Amazon Chime Voice Connector - PSTN Audio
- AWS Lambda - SIP media application Handler -smaHandler.js
- AWS Lambda - Call Query - callQuery.js
- Amazon API Gateway - Call Query
- AWS EC2 - Asterisk Server
- AWS DynamoDB - Call Info Table
- Amazon Lex Bot - Banker Bot Demo
- Nodev12+ installed
- yarn installed
- AWS Account with approriate permissions
- Service Quota allowance for Phone Numbers
yarn launch
To use the included web client SIP phone:
cd site
yarn
yarn run start
This will start a local server that can be accessed at http://localhost:3000. After the Amazon Lex Bot has processed the call will be sent to this phone and can be answered to establish two-way communication between the PSTN caller and the SIP agent.
yarn destroy
This demo is powered by Amazon Lex. Use of Amazon Lex is subject to the AWS Service Terms, including the terms specific to the AWS Machine Learning and Artificial Intelligence Services. Standard Amazon Lex charges apply. For more pricing information, please refer to Amazon Lex streaming conversation pricing.
Be sure to cleanup your deployment when finished as charges may apply for the resources deployed, and will continue to be charged if you do not remove them.
The demo will deploy one possible call flow, but many more options are possible. Below are two other options that could be used depending on your infrastructure and configuration.
In this example, calls from the PSTN will be sent to the Amazon Chime SDK PSTN Audio first rather than an existing SIP trunk. After the call is processed in the Amazon Lex Bot, the Amazon Chime PSTN Audio will use the CallAndBridge action to direct the call an Amazon Chime Voice Connector or PSTN phone number. The media will remain connected to the SIP media application for the duration of the call. This call flow can used if you have no need to keep an existing SIP trunk.
In this example, calls from the PSTN use an existing SIP trunk, however, after the call is processed in the Amazon Lex Bot, instead of returning a Hangup action, a CallAndBridge action is returned so the call can be routed to the desired destination. This destination can be a SIP target using Amazon Chime Voice Connector or a PSTN phone number. The media will remain connected to the SIP media application for the duration of the call. This call flow can be used if your telephony infrastructure cannot easily make complex routing decisions based on queried data.