pdf_gross.gif SIGTRAN - Protocol Analysis & System Integration

[2-day course, Euro 2,350.- (net) per participant]



  • The Legacy CCS7-Protocol Stack
    • Overview of the Presented CCS7-Protocols
  • Introducing SIGTRAN
    • The CCS7-Protocol Stack in Case of SIGTRAN
  • Introduction to SCTP
    • Important SCTP-Functions
    • Important SCTP-Terminology

      Association, ASP’s and AS’s, Multihoming, Path, Well known SCTP-Port Numbers, Stream, Chunk, Chunk Bundling, SCTP-Packet, Primary, Idle and Inactive Paths, Heartbeating

  • Overview of the Adaptation Layers
    • SUA
    • M3UA
    • M2UA
    • M2PA
    • IUA / DUA
    • ISUA
    • TUA
  • Advantages of SIGTRAN vs. CCS7-based Transport
    • Best of both Worlds
    • Use of lower Cost Equipment
    • Easy Deployment
    • Overcomes inherent CCS7-Resource Limitations
  • QoS-Considerations
    • Reliability related QoS-Requirements
    • Delay related QoS-Requirements
  • Future and Alternatives of SIGTRAN
    • Use Case 1: Call Establishment (Q.931-related / UNI)
    • Use Case 2: Call Establishment (ISUP-related / NNI)
    • Use Case 3: AAA-Services
    • Use Case 4: IN- and CAMEL-Services
    • Use Case 5: Access Network / Core Network Interconnection

backtotop.gifReviewing Important Assets of the CCS7 Protocol Suite

  • Network Topology
    • Overview
    • Another View – Introducing SP/SEP/SSP, STP and SCP
  • Routing Issues
    • Data Transfer & Routing within and among CCS7-Networks
      Routing through MTP-3, Signaling Point Code (SPC), Network Indicator (NI), The Routing Label
    • End-to-End Routing through the SCCP
    • Loadsharing of CCS7-Signaling Traffic between SP’s
      Principles, Loadsharing when STP’s are involved
  • CCS7-Frame Formats
    • MSU-Format
    • FISU-Format
    • LSSU-Format


  • Operational Issues
    • CCS7-Link Setup
      Before Link Establishment, Link Alignment Initiated, Test Phase, Layer 3 Message Exchange
    • CS7-Link Change Over (COO / COA)
    • SCCP-Connection Operation and Identificatio

backtotop.gifDetails of SCTP

  • Association Establishment
    • Overview
    • Detailed View

      Triggering the Transmission of an INIT-chunk, Reception of an INIT-chunk / Generate State Cookie, Content of an INIT-ACK-chunk, Generate COOKIE-ECHO, Receive COOKIE-ECHO / State Cookie Authentication, Transmit COOKIE-ACK / Confirm Association Establishment

  • Association Management and Operation
    • Overview

      Heartbeating, Path MTU-Discovery (PMTU), RTO-Determination, User Data Transfer Process, Association Release

  • Detailed Consideration of Heartbeating
    • Consequences of unsuccessful Heartbeating
      RTO-Expiry, Error-Counter = Path.Max.Retrans
    • Example of a HEARTBEAT-Chunk
  • Details of RTO- and RTT-Measurements
    • Interpretation of these Formulas
  • User Data Transfer Process
    • Process Overview
    • Congestion Control in SCTP
    • Slow Start and Congestion Avoidance Operation
      Slow Start and Congestion Avoidance Operation (Important Rules upon Initialization, Behavior in Slow Start [RFC 2960 (7.2.1)], Behavior in Congestion Avoidance [RFC 2960 (7.2.2)], Important Rules upon Packet Loss [RFC 2960 (7.2.3)], Important Rules upon RTO-Expiry [RFC 2960 (7.2.3)], Important Rules when Paths are idle for some (configurable) Time)
    • Acknowledging DATA-Chunks
      Good Case (all Chunks are acknowledged) (TSN-Numbering, Delayed Acknowledgements, No of Duplicate TSN), Bad Case (Chunk needs to be retransmitted) (Error Description, Immediate Acknowledgement, Fast Retransmit Algorithm in SCTP, Interpretation of the Gap Block Information Element)
  • Association Release
  • Security Threats for SCTP
    • DoS-Attack
    • Flooding with SCTP-Chunks
    • MitM-Attack: Eavesdropping
    • MitM-Attack: Unrecognized Data Alteration
  • SCTP Packet and Chunk Format
  • Selected Chunk Types
    • The DATA-Chunk
      The U-Flag (Unordered), The B-Flag (Beginning Fragment) , The E-Flag (Ending Fragment)
    • The SACK-Chunk
    • The INIT-Chunk
      Chunk Flags, Initiate Tag, Number of Streams (Inbound and Outbound), Initial TSN, Cookie Preservative, Supported Address Types
    • The INIT-ACK-Chunk
    • The AUTH-Chunk
      Shared Key Identifier, Message Digest Algorithm Identifier
  • Important SCTP Parameters
    • Timers
      Valid.Cookie.Life, RTO.Initial, RTO.Min, RTO.Max, HB.Interval, SACK-Delay, Chunk Bundling Timer
    • Counter
      Association.Max.Retrans, Path.Max.Retrans, Max.Init.Retransmits
    • Other Parameters

      RTO.Alpha, RTO.Beta, a_rwnd

backtotop.gifDetails of some interesting User Adaptation Layers

  • Protocol Stack View and Implementation Issues
    • M2PA – with SGW-Involvement
      Typical Implementation
    • M2PA – all IP-Architecture
    • M2UA – with SGW-Involvement
      Typical Implementation
    • M2UA – all IP-Architecture
    • M3UA – with SGW-Involvement
      SCCP-Based Routing in case of M3UA, ISUP-Based Routing in case of M3UA (Call from the PSTN hits the GMSC-S, Relay to SGW and Routing Decision within SGW, Relay to HLR of called Subscriber and Request for MSRN, Relay of IAM to Target MSC-S)
    • M3UA – all IP-Architecture
      Example of an M3UA-Data Message (Iu-cs Interface)
    • SUA – with SGW-Involvement
    • SUA – all IP-Architecture
    • Summary: When to use M2PA, M2UA, M3UA or SUA …
  • Redundancy Modes & Options
    • The N+K Redundancy Model
    • ASP-Management
      ASP-Up-Procedure (N + K = 2 + 1), ASP-Activation-Procedure (2 + 1 / Loadshare Mode), ASP-Traffic Failover-Procedure (2 + 1 / ASP-Outage)
  • ASP-Traffic Failover-Procedure (2 + 1 / ASP-Outage)
  • SCTP-Associations and Streams in Context with important XUA-Protocols
    • M2PA
    • M2UA
    • M3UA
    • SUA

backtotop.gif Practical Operation and Test of SIGTRAN

  • Showstoppers and Stumbling Stones
    • Overview
      Network-Internally, Interworking with CCS7-Network, Interworking through NAT/NAPT, VPN-Operation
    • Coping with NAT/NAPT
      Problem Description, Resolution Approaches
    • Coping with IPsec- and IKE-related Problems
      Overview, Approach: Use Application Server Clustering instead of Multihoming, Protocol Stack Details (SGSN to HLR with two SEG’s and NAT)
  • SIGTRAN Testing
    • Important Test Areas
      Performance Tests, Interoperability Tests, CCS7-Conformance & Interworking Tests
    • Possible Setup for Interoperability Tests CCS7 / SIGTRAN
    • Possible Setup for SIGTRAN Node Testing