126.96.36.199. Restrictions for DSP Builder Designs with Avalon Streaming Interface and AXI4-Stream Blocks
The Avalon streaming and AXI4-Stream interface specifications only allow a single data port per interface. To handle multiple data ports through a single Avalon streaming or AXI4-Stream interface, pack them together into a single signal, then unpack on the other side of the interface. For the maximum width for a data signal, refer to the Avalon Interface Specifications.
Use the BitCombine and BitExtract blocks to pack and unpack.