+.SS rate
+delay packets based on packet size and is a replacement for
+.IR TBF .
+Rate can be
+specified in common units (e.g. 100kbit). Optional
+.I PACKETOVERHEAD
+(in bytes) specify an per packet overhead and can be negative. A positive value can be
+used to simulate additional link layer headers. A negative value can be used to
+artificial strip the Ethernet header (e.g. -14) and/or simulate a link layer
+header compression scheme. The third parameter - an unsigned value - specify
+the cellsize. Cellsize can be used to simulate link layer schemes. ATM for
+example has an payload cellsize of 48 bytes and 5 byte per cell header. If a
+packet is 50 byte then ATM must use two cells: 2 * 48 bytes payload including 2
+* 5 byte header, thus consume 106 byte on the wire. The last optional value
+.I CELLOVERHEAD
+can be used to specify per cell overhead - for our ATM example 5.
+.I CELLOVERHEAD
+can be negative, but use negative values with caution.
+
+Note that rate throttling is limited by several factors: the kernel clock
+granularity avoid a perfect shaping at a specific level. This will show up in
+an artificial packet compression (bursts). Another influence factor are network
+adapter buffers which can also add artificial delay.
+