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IMS Load Testing


LM ToolsTM simulates IMS servers like P-CSCF, I-CSCF, S-CSCF, application servers. Additionally it simulates millions of IMS clients to load IMS servers like P-CSCF, I-CSCF and S-CSCF. Using LM Tools FlexiSIP module it is easy to simulate SIP specific scenarios. In a typical IMS network UE (user equipment) interfaces with P-CSCF. Be it registration or call, IMS message flows are bit different than normal SIP message flows. However with proper configuration you can simulate IMS registration, call and supplementary services message flows. Please refer below diagram for more details.


In case you are looking to simulate other interface messages (text or binary or mix of text and binary), you can do so using LM Tools apat(any product any test) module. Typically apat is capable of simulating any text / binary call flows, extract data and use it in future transactions.

Features - High Level
  • Registration
  • Call setup
  • Session Modification
  • DTMF
  • Call Hold
  • Call Transfer
  • Call Termination
  • Instant messaging
  • Presence
  • Unregistration
Features - Detail

Different kind of transports supported for signalling are

  • TCP
  • UDP
  • SCTP
  • TLS
  • Web socket
  • Secured web socket

Various audio codes supported are

Various video codecs supported are

RTP security supported using

  • SRTP
  • Key exchange using DTLS

Various media transports supported are

  • UDP
  • DTLS

To avoid NAT / Firewall issues below features are supported

For message/sequence manipulation below functionalities are supported

  • Addition of new headers
  • Modification of existing headers
  • Removal of existing headers
  • Introduction of stand-alone transactions
  • Define your own out of box call flows / transactions as you need
  • Inject any other custom text / binary messages during call

In addition to that you can have wide range templates for message variations to simulate required call flow.

Statistic / Report

As the IMS test goes on, you will see the result in test summary table as shown below.

IMS Load Testing Summary

If you want to see reports how IMS test fared over a period of time, you can look at graphs provided by LM Tools (Drawn on basis of data captured every 15 second). You can see graphs for network traffic (TCP, UDP, SCTP, DTLS, TLS, Websocket, Secured Websocket) etc, media streams / sessions, calls, transactions, ports used etc.

Certain graphs are shown below for visual representation.

Udp bytes

Wss bytes

Sip calls

Media sessions

RFC / Standard Compliance

LM Tools supports wide range of standards used for IMS specification / standardization. Some of these RFC / standards are listed below.

  1. RFC 3261 ( SIP base)
  3. RFC 3262 ( SIP method PRACK )
  4. RFC 3311 ( SIP method UPDATE )
  5. RFC 3312 ( SIP Precondition)
  6. RFC 3264 ( Offer Answer Model)
  7. RFC 3265 ( SIP specific Event notification)
  8. RFC 3515 ( SIP method REFER )
  9. RFC 3856 ( SIP presence event package )
  10. RFC 3903 ( SIP method PUBLISH )
  11. RFC 7315 ( P-Header extension )

Also related 3GPP specifications are supported.

  1. ETSI TS 124 228 V5.15.0 (2006-09) , 3GPP TS 24.228 V5.15.0 (2006-09) - for 2G, 3G and LTE
  2. 3GPP 24.229 - IMS client call flows
  3. GSMA Document FCM.01 for VoLTE.

In addition to all these, you can modify message content, message sequence in a flow as well. Almost all kind of call flows you will be able to simulate with proper configuration.

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