2.2.2.3.1 Client Bitmap Cache Error PDU

The Bitmap Cache Error PDU is sent by clients that support persistent bitmap caching and encounter caching errors. RDP 4.0, 5.0, 5.1, 5.2, 6.0, 6.1 and 7.0 servers honor up to five Bitmap Cache Error PDUs in a session.


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tpktHeader

x224Data

mcsSDrq (variable)

...

securityHeader (variable)

...

bitmapCacheErrorPduData (variable)

...

tpktHeader (4 bytes): A TPKT Header, as specified in [T123] section 8.

x224Data (3 bytes): An X.224 Class 0 Data TPDU, as specified in [X224] section 13.7.

mcsSDrq (variable): Variable-length, Packed Encoding Rules encoded (PER-encoded) MCS Domain PDU (DomainMCSPDU) that encapsulates an MCS Send Data Request structure (SDrq, choice 25 from DomainMCSPDU), as specified in [T125] section 11.32 (the ASN.1 structure definitions are specified in [T125] section 7, parts 7 and 10). The userData field of the MCS Send Data Request PDU contains a Security Header and a Bitmap Cache Error PDU Data (section 2.2.2.3.1.1) structure.

securityHeader (variable): Optional security header. The presence and format of the security header depends on the Encryption Level and Encryption Method selected by the server ([MS-RDPBCGR] sections 5.3.2 and 2.2.1.4.3). If the Encryption Level selected by the server is greater than ENCRYPTION_LEVEL_NONE (0) and the Encryption Method selected by the server is greater than ENCRYPTION_METHOD_NONE (0) then this field MUST contain one of the following headers:

  • Non-FIPS Security Header ([MS-RDPBCGR] section 2.2.8.1.1.2.2) if the Encryption Method selected by the server is ENCRYPTION_METHOD_40BIT (0x00000001), ENCRYPTION_METHOD_56BIT (0x00000008), or ENCRYPTION_METHOD_128BIT (0x00000002).

  • FIPS Security Header ([MS-RDPBCGR] section 2.2.8.1.1.2.3) if the Encryption Method selected by the server is ENCRYPTION_METHOD_FIPS (0x00000010).

If the Encryption Level selected by the server is ENCRYPTION_LEVEL_NONE (0) and the Encryption Method selected by the server is ENCRYPTION_METHOD_NONE (0), then this header MUST NOT be included in the PDU.

bitmapCacheErrorPduData (variable): The actual contents of the Bitmap Cache Error PDU, as specified in section 2.2.2.3.1.1.