I finished my AD review for five softwire documents that I believe are closely related, and last-called them as a group so that interested parties could review them that way. These documents all solve largely the same problem, but in usefully (IMHO) different ways from an operational perspective. If you intend to read all five documents and aren't currently very familiar with how this technology works, I would suggest reading the lw4over6 document first, the map-dhcp document second, the map document third, the map-t document fourth, and the 4rd document fifth. This is just my personal opinion on how best to bootstrap your understanding, and shouldn't be taken to mean that I prefer one document to another.