#49: observation of on-demand mobility
Changes (by seilj...@av.it.pt):
* cc: seilj...@av.it.pt (added)
Comment:
The on-demand draft proposed three source IP address types, enabling
applications to configure the required type in the IP stack, according to
IP mobility requirements. Particularly, the sustained IP address is
proposed to provide on-demand IP mobility, which aims at activating IP
mobility support operation upon an MN's movement.
Delivering the defined flag, IPV6_REQ_SUSTAINED_IP, from an application to
the IP stack through the socket API does not ensure the observation of on-
demand mobility principle where IP mobility is provided upon an MN’s
movement, because an initiated application may be served with IP mobility
even though the MN has not moved from the current serving network where
the IP prefix/address was assigned for the application. As a result, IP
mobility is activated before needed.
An example scenario raising the aforementioned issue is as follows;
1. The MN is configured with one or more Nomadic IP addresses.
2. Once an application requests “sustained IP address” to the IP stack, it
will obtain a sustained IP address through a protocol procedure between
the MN and network.
3. Other application initiated over the same serving network will use the
same sustained IP address while the MN remains connected at the same
serving network.
4. The MN moves to another access network, and the previous (mobile)
sessions are working. A new application requests a sustained IP address.
The existing sustained IP address is assigned to the new application as a
sustained IP address is already available in the IP stack.
5. As a consequence, the new session is served by a remote IP mobility
anchor with necessary management functions, though the MN has not moved
yet.
Moreover, we can suppose an example over a different address assignment
strategy, where each network assigns sustained IP addresses, i.e.
sustained IP address assignment by default, enables an MN to have multiple
sustained IP addresses. When a new application is initiated and needs a
sustained IP address, the IP stack may or not select the locally assigned
one in the context of the default source IP address selection mechanism
[RFC6724][RFC5014], as the application has no means to explicitly request
such a demand to the IP stack.
For providing the full on-demand mobility when using sustained IP address,
a new address preference flag will be needed, letting the IP stack select
a sustained IP address assigned from the current serving network. If not
available, it should request a sustained IP address from the serving
network.
--
-------------------------+-------------------------------------------------
Reporter: | Owner: draft-ietf-dmm-ondemand-
seilj...@av.it.pt | mobil...@tools.ietf.org
Type: defect | Status: new
Priority: critical | Milestone:
Component: ondemand- | Version:
mobility | Resolution:
Severity: Submitted |
WG Document |
Keywords: on-demand |
mobility |
-------------------------+-------------------------------------------------
Ticket URL: <http://trac.tools.ietf.org/wg/dmm/trac/ticket/49#comment:1>
dmm <http://tools.ietf.org/dmm/>
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