![](https://csdnimg.cn/release/download_crawler_static/15736850/bg3.jpg)
J. Tao
et al.
Anti-attack for channel assignment in WMNs
Ta b l e I . The contents of verification in the anti-attack channel
assignment.
Scheme CUM CCM CSO SAM
Ms
Ref. [24] Yes No Yes No No
SmartC [26] Yes Yes No No No
Ref. [27] Yes Yes No No No
SeCA [28] No Yes Yes No Yes
CUM, channel usage message; CCM, channel change message; CSO,
channel switch operation; SAM, security alarm message;
Ms
, message
sender.
attacks based on our insights into the possible security risks
and possible attacks.
3. ATTACKS IN CHANNEL
ASSIGNMENT
In this section, we investigate the attack process, focusing
on the cases where the state messages and the correspond-
ing operations of channel assignment are exploited in the
network, respectively.
3.1. The traditional channel assignment
process
We consider the channel assignment among nodes, most
of which are trustable and equipped with multi-radios and
multi-channels, in WMNs. Most of the existing channel
assignment schemes usually follow five steps in turn: col-
lect information, calculate channels, notify changes, assign
channels and sleep. Shown in the dotted frame of Figure 1,
the channel assignment scheme starts the channel compu-
tation with the gathered channel information. If needed, it
then broadcasts the channel change notification and con-
ducts the channel assignment. Finally, it goes into sleep
until a trigger event occurs. The trigger event, which can
happen periodically or be triggered by some special net-
work state, will restart the channel assignment from the
first step.
Seen from the steps of channel assignment, there are
two serious security problems: (i) the distributed channel
assignment needs the exchanging the usage information of
radios and channels, which provides the chance for mali-
cious nodes to initiate attacks; and (ii) with the assumption
that all nodes are trustable in most of the channel assign-
ment schemes, each node decides its channel assignment
and notifies its neighbors without verification. Besides,
the neighbors conduct the channel assignment for the
corresponding radios without any information verification.
3.2. Channel usage message attack
In the collect information process in channel assignment,
the node information is collected before channel assign-
ment in centralized or distributed algorithms. The node
information, with which the channel assignment is con-
ducted, mainly includes the result of channel usage, for
example, the number of the radios and the channels that
each radio occupies, and is referred to as channel usage
message (CUM). The CUMs usually contain different
contents in different channel assignment algorithms. For
example, [7,9,29] and [11,12,30,31] include the network
load or throughput in the CUMs. In [5] and [10], the
amount of the links, which use the same channel in the
interference region, is added into the CUMs. The special
information for interference reduction is also collected and
added into the CUMs in [13].
The nodes request the CUM from the corresponding
nodes, which will respond to the request with the informa-
tion including signal-to-interference-plus-noise ratio [9],
traffic load [12], the flow number [7] or the channel utiliza-
tion ratio [10]. The CUM attack exploits the information,
Figure 1. The channel assignment process with joint anti-attack scheme. CUM, channel usage message; SAM, security alarm
message; CCM, channel change message.
Security Comm. Networks
(2014) © 2014 John Wiley & Sons, Ltd.
DOI: 10.1002/sec