The Network Simulator ns-2: Verification of Validation Tests


Notes: Some of the ns-2.0b17 tests differ from the results in the May 1997 version of the Simulator Tests document in that the Reno retransmit timer expires sooner in the current release of ns. "Test-all" was revalidated in October, 1997, after some more corrections were make to TCP's retransmit timer algorithms.


Notes: Two of the tests (sack4, sackB2) in the ns-2.0b17 release differed from the results in ns-1 in that there are slight differences in timing in sending packets after a Fast Retransmit. This is most likely due to differences between the two simulators in taking into account the size of the SACK packet in computing the transmission time.

Comparisons of Tahoe, Reno, and SACK TCP:

Notes: The two Reno tests with three and four packet drops give different performance in ns-2.0b17 and later releases than the figures in the paper, in that the Reno retransmit timer expires sooner in ns-2.0b17. The ns-2.0b17 release includes a bug fix so that the retransmit timer is NOT backed off during Fast Retransmit.

Ns Simulator Tests for Random Early Detection (RED) Gateways:

Notes: The tests with the flow manager (flows, flows1, and flowsAll) do not run in ns-2 for "test-all-red-v1", because ns-2's backward compatibility mode does not include the flow manager interface.

Automatic Validation

For the test suites listed in the file "validate", the validation output has been included in the ns distribution and repository for automatic validation. All of these tests are validated as running correctly before each release.