Abstract:
The Smart Grid is expected to utilize a wireless infrastructure for power data collection in its Advanced
Metering Infrastructure (AMI) applications. One of the options to implement such a network infrastructure
is to use a wireless mesh network based on IEEE 802.11s mesh standard. However, IEEE 802.11s
standard relies on MAC-based routing and thus requires the availability of MAC addresses of destinations.
Due to large size of AMI networks, this creates a broadcast storm problem when such information is to be
obtained via Address Resolution Protocol (ARP) broadcast packets. In this paper, we propose a mechanism
to significantly alleviate such broadcast storm problem in order to improve the scalability of 802.11s and
thus make it better suited for Smart Grid AMI applications. Our contribution is adapting 802.11s standard
for addressing ARP broadcast storm problem in a secure and efficient manner. Specifically, we utilize the
proactive Path Request (PREQ) packet and Path Reply (PREP) of layer-2 path discovery protocol of
802.11s, namely HWMP, for piggybacking ARP information. In this way, the MAC address resolution is
handled during routing tree creation/maintenance and hence the broadcasting of ARP requests by the
smart meters (SMs) to learn the MAC address of the data collector (i.e., the gateway/root node) is completely
eliminated. Furthermore, since piggybacking the ARP via PREQ may pose vulnerabilities for possible
ARP cache poisoning attacks, the data collector also authenticates the messages it sends to SMs by
using Elliptic Curve Digital Signature Algorithm (ECDSA). We have extensively analyzed the behavior and
overhead of the proposed mechanism using implementation of IEEE 802.11s in ns-3 simulator. The evaluations
for both UDP and TCP show that compared to the original ARP broadcast operations, our approach
reduces the end-to-end delay significantly without negatively impacting the packet delivery ratio and
throughput.
