CONNECTION_ID_LIMIT_ERROR
QUIC CONNECTION_ID_LIMIT_ERROR (0x09) is sent when too many connection IDs have been provided. QUIC allows endpoints to use multiple connection IDs for migration and privacy. The active_connection_id_limit transport parameter caps how many IDs may be active simultaneously. Exceeding this limit terminates the connection.
Code
0x09
Decimal
9
Standard
RFC 9000 §20
Description
QUIC connection IDs serve two purposes: enabling connection migration (a client can switch IP addresses while maintaining the same logical connection) and providing unlinkability (rotating connection IDs prevents network observers from correlating packets). Each endpoint advertises how many connection IDs it can track simultaneously via the active_connection_id_limit transport parameter. The peer must not provide more NEW_CONNECTION_ID frames than this limit. If too many connection IDs are issued, the receiver sends CONNECTION_ID_LIMIT_ERROR. This error is implementation-specific and depends on the resource constraints of the QUIC implementation. Implementations that perform connection migration aggressively (e.g., mobile clients frequently changing networks) must be aware of this limit and retire old connection IDs before requesting new ones.
Common Causes
- –Peer issued more NEW_CONNECTION_ID frames than active_connection_id_limit allows
- –Connection ID retirement not keeping pace with issuance
- –QUIC implementation bug not tracking the connection ID limit