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Research Article: Althalji et al 77
Fig. 3: HERE Base object
Fig. 2: ICMPv6 message format [16]
2- Control Message Option Format [16] :
HERE Base object No type of options was proposed, so padding
HERE Base object is proposed to contain the will be used in proposed message. The general
following fields shown in Figure 3 : form of option contains three parts (Type,
1- Flags: 8 bits. only 2 bits are reserved for S and Option Length, Option Data). For padding
H. the 6 bits remaining unused in the Flags field option, the fields will be as following :
and reserved for flags. The field must be set to • Option Type: 8-bit, the value (0x00,0x01) is
zero by the sender and must be ignored by the for padding type .
receiver . • Option Length: 8-bit, measured in octets, not
(STOP) S: the 'S' flag indicates that the mobile including the Type and Length fields .
node has stopped and sends a HERE message to • Option Data: consists of N-2 zero octets .
its child nodes . The Pad1: option is used to add an octet of zeros
(LISTEN) L: the 'H' flag indicates that the node for alignment. it has neither option length nor
has heard Here message that is sent by mobile option data. The value of this type is 0x00. Pad1
nodes and it is still within its radio range even is shown in Figure 4 .
after its movement, so the mobile node does
not need to find a new parent node. However,
if it moves and no such message arrives, the Fig. 4: Pad1
mobile node needs to find a new parent node
as soon as possible to reduce the delay caused The PadN: option is used to add two or more
by separation resulted by moving the mobile octets of zeros. The value of this type is 0x01.
modes when they change their place . PadN is shown in Figure 5 .
The values of all flag fields remain zero when a
message is sent by the mobile node to its parent
and child nodes if it moves to let them know .
Fig. 5: PadN
) 0,0 (I MOVE TO HERE .
Proposed protocol rules
) 0,1 (LISTEN I’M HERE A mobile node must reconnect with a parent
node within 5 seconds after it stops moving [17] ,
) 1,0 (I STOP HERE .
so the following rules is suggested for proposed
(1,1) Invalid state. protocol :
•After sending a HERE message, a timer (HERE
INTERVAL: 2.5 seconds) is triggered. If the
SJSI – 2023: VOLUME 1-1
