Setting the SACK Delay Timer

An SCTP Selective Acknowledgement (SACK) is sent to the peer endpoint to acknowledge received DATA chunks and to inform the peer endpoint of gaps in the received subsequences of DATA chunks. Section 6.2 of RFC 4960 sets a specific requirement for a SACK Delay timer that specifies the maximum interval between the reception of an SCTP packet containing one or more DATA chunks and the transmission of a SACK to the packet originator.

Use the following procedure to set the SACK Delay timer.

1. From superuser mode, use the following command sequence to access network-parameters configuration mode.

   ORACLE# configure terminal
   ORACLE(configure)# system
   ORACLE(system)# network-parameters
   ORACLE(network-parameters)#

2. Use the sctp-sack-timeout parameter to assign a value to the SACK Delay timer.

   Allowable values are integers within the range 0 through 500 which specify the maximum delay (in milliseconds) between reception of a SCTP packet containing one or more Data chunks and the transmission of a SACK to the packet source. The value 0 indicates that a SACK is generated immediately upon DATA chunk reception

   In the absence of an explicitly configured integer value, sctp-sack-timeout defaults to 200 ms (the recommended default value from RFC 4960).

   ORACLE(network-parameters)# sctp-sack-timeout 200
   ORACLE(network-parameters)#

3. Use done, exit, and verify-config to complete configuration of the SACK Delay timer.

   ORACLE(network-parameters)# done
   ORACLE(system)# exit
   ORACLE(configure)# exit
   ORACLE(configure)# exit
   ORACLE# verify-config
   ---------------------------------------------------------------------
   Verification successful! No errors nor warnings in the configuration
   ORACLE#