Книга: Iptables Tutorial 1.2.2

SCTP HEARTBEAT chunk

SCTP HEARTBEAT chunk

The HEARTBEAT chunk is sent by one of the peers to probe and find out if a specific SCTP endpoint address is up. This is sent to the different addresses that was negotiated during the initialization of the association to find out if they are all up.

Type - bit 0-7. The type is always set to 4 for HEARTBEAT chunks.

Chunk flags - bit 8-15. Not used today. Might be applicable for change. See SCTP Common and generic headers for more information.

Length - bit 16-31. The length of the whole chunk, including the Heartbeat Information TLV.

Heartbeat Information TLV - bit 32-n. This is a variable-length parameter as defined inside the RFC 2960 - Stream Control Transmission Protocol document. This is a mandatory parameter for the HEARTBEAT chunks that contains 3 fields, info type = 1, info length and a sender-specific Heartbeat Information parameter. The last field should be a sender-specific information field of some kind, for example a timestamp when the heartbeat was sent and a destination IP address. This is then returned in the HEARTBEAT ACK chunk.

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