DLC Enhancements

There are significant differences between the IBM DLC interface specification and the implementation of the Win32 DLC. These differences are as follows:

• All 16-bit segment offsets in command control blocks have been replaced by 32-bit flat pointers.
• The buffer pool is managed by the DLC driver. Applications can no longer define the segment size of the buffer pool or add new buffers to the pool. However, the application must always check the size field in the buffer header.
• The members of the command control block that are specific to IBM Token-Ring hardware have been removed. These members are not available on Ethernet adapters.
• Win32 events replace OS/2 semaphores as the mechanism used to signal the completion of asynchronous commands.
• Global resources that were shared by all applications are now available to each application separately. These resources include functional addresses, group addresses, link stations, SAP stations, and direct stations.
• Applications can define a 48-bit multicast address on Ethernet adapters using the LLC_DIR_SET_MULTICAST_ADDRESS command. This overwrites the 32-bit broadcast address set by the LLC_DIR_SET_GROUP_ADDRESS command.
• Applications can send several frames from a DLC station with the LLC_TRANSMIT_FRAMES command.
• Windows NT: The application identifier and application key members of the command control block are obsolete. They have been superseded by an optional security descriptor in the LLC_EXTENDED_ADAPTER_PARMS structure.