Here is a description of the wire entanglement and trous de loups at Eshowe by Captain Wynne, R.E. who was in charge of their construction.
From the “MEMOIR OF CAPT. W. R. C. WYNNE, R.E.”
7th February 1879
“We are still strengthening the Fort, and I begin to have great confidence in it, both for its offensive powers as well as for its defensive and protective. There ought hardly to be a casualty from the fire from outside; and even if they come in many thousands and persevere in spite of heavy losses to the edge of the ditches, I don't think they will find it easy to get in. I am now beginning to make a variety of obstacles to check their advance should they arrive within thirty yards of the place: - Shallow little pits, with stakes at the bottom chequer-wise; entanglements of wire; and, by-and-by, explosive traps.”