Newsletter: GL Announces Skinny Protocol Emulation and Analysis

Welcome to another October, 2013 issue of GL Communications' Newsletter providing information and insight into our MAPS™ Skinny Protocol Emulator and PacketScan™ - Skinny Protocol Analysis applications.


Skinny Call Control Protocol (SCCP), also referred to as "Skinny," is a Cisco Systems proprietary signaling and control protocol used to communicate between IP devices and Cisco Unified Communications Manager for call establishment, teardown, and control in VoIP environments. It is widely deployed in VoIP enterprise solutions and is increasingly supported by third-party service provider. It is a simple, lightweight, very feature-rich stimulus protocol deployed in conjunction with Cisco IP phones.

Typical Call Flow Scenario

The following call flow depicts the typical Skinny Client Control procedure -

  • Registration 
    IP Phone registers its IP, type, & name with the Cisco Call Manager (CCM), and provides its "Capabilities" (voice/video codec supported) to CCM capability request message.
  • Call Control (setup, teardown, and statistics)
    • Phone periodically sends "KeepAlive" messages to the CCM. Alarms are also sent in case of network errors.
    • Offhook (place call) - When the phone goes offhook (place call), the CCM instructs with the lamp on/off, through the prompt, key settings, and the dialtone messages.
    • Onhook (end call) - When the phone goes onhook (end call), the CCM instructs the phone to stop transmitting, close the channels, set the call status to disconnect, and send the default user prompt.
  • Media (audio) Stream Control 
    Media Transmission includes Conference ID, Pass through Party ID, Remote IP & Port Address, Packet, Payload Capability, Max Frames per Packet details.

Skinny Signaling and Traffic Emulation

GL's MAPS™ (Message Automation and Protocol Simulation) is an advanced and versatile protocol simulator/tester that can simulate a variety of protocols encountered in the telecom space, including ISDN, CAS, SS7, VoIP, Wireless (2G,3G & 4G) and others.

MAPS™ is now enhanced to support 'Skinny' - SCCP, Cisco Systems proprietary signaling and control protocol.

GL's MAPS™ Skinny Emulator can be used to emulate IP Phones (Skinny Clients) in VoIP environment.

The supported call control functionalities include:

  • registration and management
  • call control (setup, teardown, and statistics)
  • media (audio) stream control

In addition to call simulation in VoIP environment, the emulator also supports error tracking, regression testing, conformance testing, load testing, and message generation. It can run pre-defined test scenarios against test objects in a controlled & deterministic manner.

MAPS™ Skinny Emulator supports powerful utilities like Message Editor, Script Editor, and Profile Editor, which allow new scenarios to be created or existing scenarios to be modified.

Main Features

  • Emulates Skinny Call Control Protocol (SCCP) clients (IP Phones)
  • User-friendly GUI for configuring the SCCP signaling links over IP
  • Ready scripts for registration, call control (setup, teardown, and statistics) procedures
  • Logging of all messages in real-time
  • Supports customization of placing and answering calls using Profile editor and Message editor
  • Provides protocol trace with full message decoding of the call control messages
  • Script based & protocol independent software architecture
  • Provides call reports with associated captured events and error events during call simulation
  • Option to send reports to database accessible via web interface

Call Emulation

Call Generation feature allows the user to simulate incoming and outgoing communications in VoIP environment. Skinny call control simulation between IP Phone (Skinny Client), and Call Manager, using proper scripts and profiles. The profile allows necessary parameters of call controls to be changed during runtime.

Inbound Call

MAPS™ Skinny configured as IP Phone (Skinny Client) can register and receive the incoming calls (Inbound) from the Call Manager (DUT).

The screenshot below shows Skinny inbound call flow

MAPS™ Skinny as IP Phone (Inbound Calls)

Outbound Call

MAPS™ Skinny configured as IP Phone (Skinny Client) can simulate outgoing communications by sending call control messages and perform media transmission after the call is established with the Call Manager (DUT). The ready scripts used can detect events and respond with appropriate actions with respect to the states.

MAPS™ Skinny as IP Phone (Outbound Calls)

The Events encountered during the progress of the calls are logged as seen in the screen below.

Outbound Call Events Log

Skinny Protocol Analysis

Detail View of Skinny Client Control Protocol

GL's PacketScan™ - an All-IP Network Monitoring software supports decoding of almost all industry standard signaling protocols including Skinny (SCCP) protocol.

The decode detail view of SCCP (Skinny) call displays the following layers:

  • MAC Layer
  • IP Layer
  • TCP Layer
  • Skinny Client Control Protocol Layer

For comprehensive information on the applications, you can visit MAPS™ Skinny Protocol Emulator and PacketScan™ web page.

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