CAD Login Step in UCCX

Here is what all event occurs when a CAD uses login to UCCX .

1. CAD will connect to the UCCX (LRM service) to check if there are licenses available. If it fails at this stage, we get the error "License Server is Down". The login screen is not even provided.
2. Once the user enters the userid/password, the same is sent to the UCCX. Now, the user is searched within the LDAP database of the UCCX. If the user is not present, we get the "Invalid User" error.
3. The AXL request is sent to the CUCM for authentication. Post that, the CTI Control is opened on the agent device. Here we either get the "Authentication fail" or the "Error with CTI or RMJTAPI" respentively if either fails.
4. User configuration is loaded from the LDAP of UCCX i.e. agent specific config such as integrated browser setting etc. and also the connection is made to all the services such as recording, chat, playback and so on.

SIP Message transaction

In my previous post i mentioned the basic architecture of a SIP network and the component involve in SIP .
In this post i am going to mention several messages that the SIP uses to initiate and drop a call.

SIP works on request/response model

The most common messages used by SIP are as follows

Register: UA (User Agent) send a message about its location to SIP server in register message
Invite: This message is sent by the caller in order to other agent to join a SIP call , This message can also be used in order to change any call parameter for a established call.
ACK : The SIP UA receive several response for a invite , This message acknowledge the final response
CANCEL: This message end a call that has not yet been established
BYE:  This message end a session or decline to take a call
OPTION: This message queries about the capability of the server.

Response for a request in SIP fall under the below categories:

1XX : This reponse designate a provisional and informational message
2XX: This response designate a  repsonse to a request  that is successful .
3XX : This response is used to designate a redirect or location change for the called UA
4XX: This response is used to designate a error condition from UA side (Request failure)
5XX: This response is used to designate a failure condition from the Server Side
6XX: This response is used to designate a global failure

Informational response:

100 Trying
180 Ringing
181 Call Is Being Forwarded
182 Queued
183 Session Progress

Success

200 OK

Redirection
300 Multiple Choices
301 Moved Permanently
302 Moved Temporarily
305 Use Proxy
380 Alternative Service

Client-error

400 Bad Request
401 Unauthorized
402 Payment Required
403 Forbidden
404 Not Found
405 Method Not Allowed
406 Not Acceptable
407 Proxy Authentication Required
408 Request Timeout
410 Gone
413 Request Entity Too Large
414 Requested URL Too Large
415 Unsupported Media Type
416 Unsupported URI1 Scheme
420 Bad Extension
421 Extension Required
423 Interval Too Brief
480 Temporarily Not Available
481 Call Leg or Transaction Does Not Exist
482 Loop Detected
483 Too Many Hops
484 Address Incomplete
485 Ambiguous
486 Busy Here
487 Request Terminated
488 Not Acceptable Here
491 Request Pending
493 Undecipherable

Server-error

500 Internal Server Error
501 Not Implemented
502 Bad Gateway
503 Service Unavailable
504 Server Timeout
505 SIP Version Not Supported
513 Message Too Large

Global failure

600 Busy Everywhere
603 Decline
604 Does Not Exist Anywhere
606 Not Acceptable

SIP Basics

SIP is a VOIP protocol and it stands for session initiated protocol , It uses text message same as http for commnication, The SIP network consist of below component.

SIP Proxy server:The proxy server works as an intermediate device that receives SIP requests from  a client and then forwards the requests on the behalf of the client. Proxy servers can provide functions such as authentication, authorization,network access control, routing, reliable request retransmission, and security. 

Redirect Server: The redirect server provides the client with information about the next hop or hops that a message should take, and the client then contacts the next hop server or user agent server directly.

Registrar Server: The registrar server processes requests from user agent clients for registration of their current location. Redirect or proxy servers often contain registrar servers

User Agent (UA) : UA comprises a combination of user agent client (UAC) and user agent server (UAS) that initiates and receives calls. A UAC initiates a SIP request. A UAS, a server application,contacts the user when it receives a SIP request.The UAS then responds on behalf of the user. CiscoUnified Communications Manager can act as both a server and a client

SIP user uses URI in a email id format for its identification,Unencrypted SIP works on port 5060 and encrypted(TLS) sip protocol works on Port 5061

SIP Packet exchange ... Coming Next...

How Gateway discover gatekeeper

We can use gatekeeper to register different gateway to a particular zone.Each zone will have only one active gatekeeper

Now how the gateway find s its gatekeeper ???

Gateway/Gatekeeper works on h323 protocol suite and h323 protocol suite is split into 3signalling

1. h225 (RAS-Registration,admission and Status)
2. h225 control signalling 
3. h245 (Media negotaiation and logical channel or transport signalling )

H225 RAS: RAS signalling work between gateway and gatekeeper on UDP port 1719 and for multicast work on UDP port (1718). In case of multicast it used the IP 224.0.1.41 to discover the gatekeeper

H225 control signalling:This is used  to setup connection between two H323 endpoints,This signalling works on TCP port 1720

H245 Media control and transport: this signalling is used to negotiate media capabilities and parameter fpor establishing logical channel,Adminssion control is also done by h245 signalling.

Gatekeeper discovery process:

1. The gateway or h323 endpoint send a GRQ(Gatekeeper request packet ) on port 224.0.1.41 of udp port 1718
2. the gatekeeper  either respond using a GCF (Gatekeepr_ confirm) or GRJ (Gatekeeper Reject ), In case of rejection it also include the reason of rejection .

 

Outbound dialer in uccx

In case of UCCX outbound dialing are of two type : Direct preview and IVR mode (IVR mode is further divided in progressive and predictive)

Direct preview:

In case of direct preview dialing

1. when a agent is in ready state and the dialer has selected a contact from the campaign manager the dialer ask the resource manager to reserve the resources

2. The resource manager change the agent to reserve state

3.  The dialer send a call to the Agent and same time initiate a popup in the agent desktop with the details of the contact, The agent either chooses to accept the call or reject the call if the Agent accept the call the call is connected , The dialer instruct the resource manager to place a outbound call from the Agent phone

4. Once the call is answered the the contact is closed by the dialer and marked as a voice call and send the details to the campain manager

IVR Mode:

In case of outbound dialer in IVR mode below  steps occurs;

1. The dialer chooses a contact  and as per the dialing mode (predictive or progressive based on algorithm ) dial the contact using the SIP via voice gateway

2. If the contact is not a live contcat which the SIP gateway can determine by using the CPA capability ,the dialer update the status accordingly in the configuration database

3. if the contact is a live contact then the dialer update the configuration database accordingly and send a SIP refer message to the SIP gateway which in turn transfer the call to the CTI route point associated with the IVR application which in turn choosea a IVR port and trigger the IVR application associated with the campaign .


The difference between these two is that in case of preview dialer the call is dialer from the Agent Phone while in IVR mode the acll is handled by a IVR application associated with the campaign.

Login issue in Cisco Agent Desktop

Recently during a deployment  project faced issue with Agent not able to login to CAD and giving error in the logs located at C:\Program Files (x86)\Cisco\Desktop\log ..

The error contain the message "Retrive value for LDAP Request Timeout from preferences"

So from the logs it seems that the CAD is timeout while initiating a login to UCCX .

Hence i increased the Timer for LDAP Authentication in the phonedev.cfg in
C:\Program Files\Cisco\Desktop\Config

and add the below line

[ReqTimeout]

Milliseconds=20000


it will increase the timeout value.

Next chnage in registry setting  in the below location
HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Calabrio\CAD\Site Setup

Change the LDAP Connection Timeout parameter value to 60

it resolved my login issue . Hope it help someone else.

ISDN CAS ( Channel associated Signalling )

CAS ( Channel associated sgnalling) is a kind of PSTN signalling for E1/T1 Link.

In case of CAS the signalling information is sent over the B Channel and hence the signalling is In Band.
Hence CAS is alos called a "Robbed bit signalling".

Below are the list of signalling used by CAS to detect phone and network events.
1. Loopstart
2. groundstart
3. E&M

The disadvantage of loopstart is that it is prone to glare (A situation where incoming and outgoing call both try to sieze a channel )

The best to use is E&M as it  provide both disconnect and answer supervision and is not prone to glare problem

Typical configuration of CAS include below command:

controller T1 0

clock source line primary

ds0-group 1 timeslots 1-24 type e&m-fgd dtmf dnis
In this case the below type command mean that it card will collect dual tone multifrequecy for DNIS for E&M
"type e&m-fgd dtmf dnis " .

You can find many such frequency or type you can select one as per your requirement....

Good Link from Cisco for T1 CAS troubleshoot..

http://www.cisco.com/en/US/tech/tk652/tk653/technologies_configuration_example09186a00801040bc.shtml