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Dear Liang Chen, The model described in Section 6.3 is
founded on some assumptions (such continuous network topology update, either
manual or automatic) and it addresses 802.21 Information Service only. The use
case that you described below is supported in principle, although the initial
AP discovery procedure might relay on 802.21 Event Service and Command service
and on certain degree of scanning. An 802.21-capable STA will detect the
presence of newly deployed APs.and it might trigger events leading to the
selection of the new network. Depending on operator policies and
mobility application controlling HO, the STA might use 802.21 these events to
trigger a HO toward the 802 network. As new APs are “discovered”
the Media Independent Information Service (MIIS) can be updated using 802.21 messages.
Note that the text in section 6.3 emphasizes this by stating that “the
MIIS list of access networks that are supported by MIIIS may also evolve” Central to the development of 802.21
specification is the fact that 802.21 does not define handover policies. The 802.21
specification supports both methods but it does not explicitly favor anyone in
particular. Network operators might choose to define these policies and exert a
tight control on their subsidized terminal equipment. User on the other hand might
want be given full access to the network of their choice and pay for this. Kind regards, Ulises From: Liang Chen
[mailto:leo.liang.chen@GMAIL.COM] Dear all, 802.21/D00.01 draft describes an mechanism for the vertical handover
decision in Sec. 6.3. With the help of networking location
information boardcast in any medium supported by 802.21, STA could aware the
surrounding networks before handover. However, I guess there are some
problems in the real scenarios. 1. Due to the cheap deployment cost of 802.11 AP, users may want
to deploy the 802.11 hot-spot in their office or home independently and without
the notification to the WWAN operators. When a user moves to their
home/office from outsides, how user's STA know there is a 802.21
supporting WiFi AP from the location information boardcast by WWAN. 2. How STA locates itself in the wireless networks map? GPS
may not work in-door and increase the cost. Moreover, I am a little confused on the different benefits of
network-initiated and MN-initiated handover mentioned in Set. 5.2. Best regards, -Liang Chen |