Towards Modeling and Testing of IP Routing Protocols

Towards Modeling and Testing of IP Routing Protocols Jianping Wu, Zhongjie Li, Xia Yin Tsinghua University, P.R.China Sophia Antipolis, France May. 26, 2003

contents • background and problem • the MP-FSM model of Routing Information Processing • a pragmatic test architecture – PADTACC • a simple test notation –RIPTS • a software tester • example test cases • conclusions and future work

RI Processing •Origination •Propagation •RIB management •Routing table calculation RI-Pro NC Routing information flows •Interface up/down •Neighbor up/down IP, TCP, UDP connections 2-layer design: NC and RI-Pro IP Routing Protocols

Testing • network communication (NC) • Basic content of routing protocols test • FSM, other state based approach • many researches (not covered in this paper) • routing information processing (RI-Pro) • Main content of routing protocols test • Specified in natural language, no formal model • challenging research (covered in this paper)

status • Formal and automatic testing • Tsinghua TTCN-1 based, etc • Agilent RouterTester, etc • Informal and manual testing • UNH IOL Interoperability test suite, etc

C D A B HDR3 HDR4 HDR1 HDR2 r1 r2 r1 r2 r2 r1 B C D A B C D A C D TTCN Problem-1: data START T1 ?C ?D ?A ?B ?C ?D ?Otherwise/Timeout +Post0F ?B ?A ?C ?D ?Otherwise/Timeout +Post0F ?Otherwise/Timeout +Post0F

TTCN Problem-2: control • TTCN is not so powerful as C,C++ • NC-part testing based on TTCN – useful, but not a good base to support RI-Pro testing (as preamble, postamble, etc) • RI-Pro testing need a correct, stable and function-rich NC-Part service • PDU code/decode (carry routing information) • State machines • Protocol configuration

test software SR2 SR1 Routing Software (SR) IUT SR3 - test IUT by simulate its working environment IUT design overview

the mp-FSM model

exportable routing protocols in a router verify a state

test architecture TTCN-2 PADTACC Parallel And Distributed Test Architecture with Centralized-Control Main Test Component (MTC) Parallel Test Component (PTC) Coordination Point (CP) Distributed Communication Utilities (DCU)

test architecture (cont’d) test system Router Under Test SR1 ifc1 PC_1 ifc2 SR2 ifc3 PC_m SRx ifcn one Main Tester, several Slave Testers compose the test system, SRs act as PTCs

requirements on test notation • Flexible and Simple to be customized • Send, Receive and State Verification statements • Specify parallel behaviors on PCOs • Formalization and Automation of Test Configurations • RIPTS: Routing Information Processing Test Script

RIPTS a test step

software tester UI: User Interface TC-Editor: Test Case Editor TM: Test Management AC: Auxiliary Channel TE: Test Execution RI-Gen: Routing Information Generation

N1: 10.1.1.0/24; N2: 10.1.2.0/24; N3: 10.1.3.0/24 IUT interface1: 10.1.1.5, metric=1; interface2: 10.1.2.5, metric=2; interface3: 10.1.3.5, metric=3 SR1 SR2 10.1.1.0/24 1 3 IUT 10.1.2.0/24 2 10.1.3.0/24 Area0 Area1 Example test scenario #1 LSA: Link State Advertisement (OSPF routing information) Fig. 10. the TOP2 Test Case Outline

N7 SR2 SR1 N1 IUT 1 N3 R6 (ASBR) 3 N2 2 4 Area1 N6 N5 Area0 N4 STUB Area2 SR3 Example test scenario #2 pco1 send top3_total5.ol pco1 recv empty.ol pco2 recv top3_total5.ol pco3 recv top3_total4.ol pco4 recv empty.ol stop pco1 recv top3_a0_noaggr.ol pco2 recv top3_a0_noaggr.ol pco3 recv top3_a1_noaggr.ol pco4 recv top3_a2_stub.ol pause TestCase 3 TestCfg testcfg1 TestEvents wait all full

conclusions • What and how to test RI processing • mp-FSM model • PADTACC architecture • RIPTS notation • Software tester • A groping walk off the TTCN road

future works • improve RIPTS and IRIT • application to similar protocols • relate to TTCN-3 • external function • interleave

Thank you. Comments and Criticisms are welcome.

Towards Modeling and Testing of IP Routing Protocols