[ns] Packet data buffering at a node

Hi,

I working on the wireless network using ns-2. My topology composed of
wireless node and fixed node. I would like to implement a buffer at the
fixed node so that when I receive a packet from the wireless node i buffer
the packet at the receiving node and the forward it later. Could any one
give me hint on how I can implement a buffer inside a node.

Thank you,

Rugambwa