specification/protocol/network/messages/inv.md

{ "title":"INV", "related":["/protocol","/protocol/network/messages/getdata.md","/protocol/network/messages/filterload.md","/protocol/network/messages/filterclear.md"] }

Notifies peers about the existence of some information (block or transaction) Based on selected services in the VERSION message, INV messages may not be sent.

If a bloom filter has been sent to this node via FILTERLOAD, transaction INVs will only be sent if they match the bloom filter.

compact int	4 bytes	32 bytes	...	4 bytes	32 bytes
vector size N of	type 1	hash 1		type N	hash N

NOTE: Since a block header is a relatively small data structure, and block propagation speed is an important network metric, a peer may send HEADER messages in place of INV messages when a block arrives.

Type

The type of the object that is available.

Type	Value
1	Transaction
2	Block
3	Filtered Block (partial block with merkle proof)
4	Compact block
5	Xthin block (Bitcoin Unlimited)
6	Graphene Block (Bitcoin Unlimited)

Implementations: C++

Hash

The hash identifier of the available object.