Section 7.2 clarify term "avoiding routing loops"

[Xavier Vilajosana]

I have a question about this text from section 7.2:

When a node joins the network, it MUST NOT send EBs before having acquired a RPL rank. This avoids routing loops and matches RPL topology with underlying mesh topology.

What is meant by "avoiding routing loops"? My understanding is that IEEE 802.15.4 TSCH simply provides for frame delivery between neighbors and does not provide frame forwarding. How would routing loops arise from running IEEE 802.15.4 TSCH?

TW> "Routing loops" in not the right term. As per your comment, IEEE802.15.4e TSCH TW> is independent from routing, but loops in the synchronization structure TW> should be avoided. TW> @Editor, please rephrase to: TW> When a node joins the network and the RPL routing protocol is used, TW> it MUST NOT send EBs before having acquired a RPL rank. This avoids TW> inconsistencies in the time synchronization structure.