NAME

  SACK_DupWithNoNewData.seq - Duplicate DATA chunk is received with no new DATA chunk

PURPOSE

  To chech that if duplicate DATA chunk is received with no new DATA chunk then the
  endpoint MUST immediately send a SACK with no delay.

SYNOPSIS

  ./SACK_DupWithNoNewData.seq [-tooloption ...] -pkt ./SACK_DupWithNoNewData.def
    -tooloption : v6eval tool option
  See Also: ../common/STD_PKT_COMMON.def
            ../common/SCTP_COMMON.def

PRE-TEST CONDITION

  Association is established between endpoint A and B. Arrange data 
  in endpoint A such that DATA message with duplicate TSN number
  are sent to endpoint B.

TEST PROCEDURE

  Endpoint A                           Endpoint B                ULP
  (ESTABLISHED)                        (ESTABLISHED)

  DATA          ----------------->
  (with duplicate TSN number)
                <-----------------      SACK (Dup Block Report)

  TEST DESCRIPTION:

  1. Send DATA message with duplicate TSN number is sent to
     endpoint B.
  2. Check A: SACK with Dup Ack Report is send to acknowledge
     the reception of DATA chunk from endpoint B with no delay.

NOTE

  None

REFERENCE

  RFC 4960

  6.2.  Acknowledgement on Reception of DATA Chunks

    When a packet arrives with duplicate DATA chunk(s) and with no new
    DATA chunk(s), the endpoint MUST immediately send a SACK with no
    delay.  If a packet arrives with duplicate DATA chunk(s) bundled with
    new DATA chunks, the endpoint MAY immediately send a SACK.  Normally,
    receipt of duplicate DATA chunks will occur when the original SACK
    chunk was lost and the peer's RTO has expired.  The duplicate TSN
    number(s) SHOULD be reported in the SACK as duplicate.

    When an endpoint receives a SACK, it MAY use the duplicate TSN
    information to determine if SACK loss is occurring.  Further use of
    this data is for future study.