Dear All; After finishing to design end to end NAT (draft-ohta-e2e-nat-00.txt), I have noticed several people working on similar idea differently using portwise routing (draft-boucadair-port-range-*, draft-ymbk-aplusp-*). So, here is my comments. 1) Having IPv4 network, where port numbers also affect routing, is equivalent to end to end NAT, though port-wise routing is more obviously end to end. Thus, most arguments in draft-ohta-e2e-nat-00.txt should be applicable to port-wise routing. End to end NAT, on the other hand, can naturally be upward compatible to legacy NAT. 2) Though port-wise routing is not NAT, proposals seems to assume CPE or some box near CPE is legacy NAT, only to loss end to end transparency. CPE should better be end to end NAT. 3) Though proposals suggest tunneling, address translation of end to end NAT is enough for redirection without affecting MTU. Masataka Ohta _______________________________________________ Ietf@xxxxxxxx https://www.ietf.org/mailman/listinfo/ietf