
464 ◾ Mobile Ad Hoc Networks: Current Status and Future Trends
In the flat architecture, all the 70 mesh routers/gateways participate on the same service set
and they all use the same channel, intra-channel; mainly the inter-channel interference further
degrades the performance. Moreover, the heavily congested flat links cause collisions and, as a
result, increased retransmission attempts and data drops due to the retransmission threshold as
seen in Figure 17.14(b).
On the other hand, the hierarchical approach of aggregating routes at different layers can
lead to far smaller routing tables, less route advertisements, quicker look-up, and less ...