A.1 SCTP Parameter Configuration
The following table provides the parameter configuration for SCTP.
Table -10 SCTP parameter configuration
| RFC Name | DSR SCTP Parameter Name | Description | RFC Recommended Default Value | Oracle Default Value | Oracle Ranges | Oracle Suggestions |
|---|---|---|---|---|---|---|
| RTO.initial | Retransmit Initial Timeout (ms) | The expected average network round-trip time in
milliseconds. This value is used to initialize the round trip time
when an association is started, before the round trip time has been
measured. It helps SCTP determine when to retransmit chunks.
Note: The parameter with the local node's connection configuration set is used by the peer initiated (responder) connection. |
3000 | 120 | 10 to 5000 | Same as RTO.min suggestion |
| RTO.min | Retransmit Minimum Timeout (ms) | The minimum amount of time to wait for an acknowledgment of a sent message. This value prevents the retransmit timeout from becoming too short in networks with very low round-trip times. | 1000 | 120 | 10 to 5000 | greater of (1.2 * average RTT) or (10 ms + average RTT) |
| RTO.max | Retransmit Maximum Timeout (ms) | The maximum amount of time to wait for an acknowledgment of a sent message. This value sets an upper limit on the exponential back-off algorithm used by SCTP for retransmission timing. Once this time is reached, retransmits are sent at a constant rate until an acknowledgment is received or the maximum number of attempts is reached. | 60000 | 120 | 10 to 10000 |
Note: Keep 3 * RMIN less than 1/6 of upper layer timeout, so the association gets enough retransition chances before upper layer timeout. |
| Retransmit Maximum Timeout for INIT (ms) | The maximum amount of time to wait for an initialization to be
acknowledged. This value overrides the Retransmit Maximum Timeout
for initialization, limiting the initial setup time. A value of 0
means the Retransmit Maximum Timeout is used for initialization as
well.
Note: The parameter with the local node's connection configuration set is used by the peer-initiated (responder) connection. |
120 | 10 to 10000 | Same as RTO.max suggestion. | ||
| Path.Max.Retrans | Number of Retransmits Triggering Path Failure | The number of consecutive unsuccessful retransmits that will cause a path of the SCTP association to be marked as failed. This value specifies how many retransmission attempts should be made to each destination before marking that destination as failed. It must be less than the "Number of Retransmits Triggering Association Failure" value. | 5 | 3 | 1 to 10 | 3 |
| Association.Max.Retrans | Number of Retransmits Triggering Association Failure | The number of consecutive retransmits that will cause an SCTP association to be marked as failed. This value specifies how many retransmission attempts should be made to all destinations for an SCTP association before it is considered failed. It should not exceed the total retransmit attempts for all destinations within the association. | 10 | 5 | 1 to 20 | 6 (to test the behaviour of re-tx for multi-homed association) |
| Max.Init. Retransmits | Number of Retransmits Triggering Init Failure | The number of consecutive retransmits for initialization and
COOKIE-ECHO chunks that will cause an SCTP connection to be marked
as failed. This value specifies how many retransmission attempts
should be made to the primary SCTP address before considering the
connection failed.
Note: The parameter with the local node's connection configuration set is used by the peer-initiated (responder) connection. |
8 | 8 | 1 to 20 | 8 |
| Acknowledgement timer | SACK Delay (ms) | The number of milliseconds to wait after receiving a data chunk before sending a Selective Acknowledgment. A non-zero value allows the application to bundle data chunks with the Selective Acknowledgment in the same SCTP datagram, reducing network packet count. Setting the delay to zero disables this wait, sending Selective Acknowledgments as quickly as possible. | User Configurable not to exceed 500 ms | 10 | 1 to 200 | 10ms or ½ RTO, whichever is less |
| HB.interval | SCTP Heartbeat Interval (ms) | The number of milliseconds between sending SCTP Heartbeat messages to a peer. Heartbeats are sent only if no user data has been sent during the Heartbeat Interval. Setting the interval to 0 disables heartbeats (not recommended). | 30000 | 1000 | 0, 100 to 300000 | 1000 |
| NA | Socket Send Buffer Size (bytes) | The socket send buffer size for outgoing SCTP messages must be at
least the product of the bandwidth and round-trip delay for the
association.
Note: The parameter with the local node's connection configuration is used by the peer-initiated (responder) connection. |
NA | 1000000 | 8000 to 5000000 | The traffic pattern on the association must be analyzed. The send buffer size should be at least the product of the bandwidth and round-trip delay for the association. |
| NA | Socket Receive Buffer Size (bytes) | The socket receive buffer size for incoming SCTP messages must be
at least the product of the bandwidth and round-trip delay for the
association.
Note: The parameter with the local node's connection configuration is used by the peer-initiated (responder) connection. |
NA | 1000000 | 8000 to 5000000 | The traffic pattern on the association must be analyzed. The receive buffer size should be at least the product of the bandwidth and round-trip delay for the association. |
| Max.Burst | Maximum Burst | Specifies the maximum number of packets that can be sent in a burst by this association. | 4 | 4 | 1 to 4 | 4 |
| NA | Max Number of Inbound Stream | Maximum number of inbound SCTP streams supported locally by the
SCTP connection.
Note: The parameter with the local node's connection configuration is used by the peer-initiated (responder) connection. |
NA | 8 | 1 to 16 | Align with peer configuration |
| NA | Max Number of Outbound Streams | Maximum number of outbound SCTP streams supported
locally by the SCTP connection.
Note: The parameter with the local Node's connection configuration is used by the peer-initiated (responder) connection. |
NA | 8 | 1 to 16 | Align with peer configuration |
| NA | Datagram Bundling Enabled | If checked, datagram bundling is enabled for the SCTP connection. | NA | checked | checked, unchecked | Checked |
| NA | Maximum Segment Size | The maximum size for any outgoing SCTP data chunk. If a message is larger, SCTP fragments it into the specified size. | 0 | 0, 64 to 1460 | Set to 0 if ICMP (Internet Control Message Protocol) is not blocked in the connection's IP path. If ICMP is blocked, set the Maximum Segment Size based on the path MTU supported by the end-to-end IP transport. | |
| Ordered Delivery | If checked, ordered delivery of the SCTP data chunk is performed. Otherwise, unordered delivery of the SCTP data chunk is performed. | unchecked | checked, unchecked | unchecked |