[EMAIL PROTECTED] wrote:
Hi Brian,
Thanks for the review! I have included answers & comments to
your comments below:
3. Service Selection Mobility Option
The Service Selection mobility option MAY be included in any Binding
Update message. It SHOULD be included at least in the Binding
Update
message that is sent for the initial binding registration when the
mobile node and the home agent do not have an existing binding. If
the Binding Update message includes any authorization related
options
(such as the Binding Authorization Data option [1]) or
authentication
related options (such as the Mobility Message Authentication option
[8]), then the Service Selection option MUST appear before any
mobility message authorization or authentication related options.
(1) I don't understand the SHOULD. Surely the default case (we just
want
basic Internet access) doesn't need this option?
The default case does not need to include the option. In that case
whatever
the HA understands as a default behavior & connectivity gets applied.
What
about rephrasing:
The Service Selection mobility option MAY be included in any Binding
Update message. If the Binding Update message includes any
authorization related options (such as the Binding Authorization Data
option [1]) or authentication related options (such as the Mobility
Message Authentication option [8]), then the Service Selection option
when present MUST appear before any mobility message authorization or
authentication related options.
This is ok, but we still need some text that says, if the service
selection mobility option is used, it needs to appear only in the
initial BU and not required in the BUs sent to refresh a binding.
(2) The final MUST could be read in two ways. Does it need clarifying
thus:
[8]), then the Service Selection option _when present_ MUST appear
before any
mobility message authorization or authentication related options.
Yes. See above.
...
o Identifier: A variable length UTF-8 [3] encoded service
identifier
string used to identify the requested service.
'ims', 'voip' and 'voip.companyxyz.example.com' are valid
examples
of Service Selection option Identifiers. At minimum the
Identifier MUST be unique among the home agents the mobile node
is
authorized to register to.
(3) Does this mean that a mobile node can request exactly one service?
Or
is it possible to send more than one Service Selection mobility option
with different identifiers, in order to request access to several
services? If it's restricted to one service, why?
The intention is that only one dedicated service per mobile ip tunnel
is allowed. This is because the selected service may affect the
allocation of the home address & home network prefix and thus the
routing in the HA. For each mobile ip tunnel we can assign only one
address / prefix.
If we were only after different QoS treatment or filtering of packets
then multiple options could probably be allowed.
The draft should say something about the number of service selection
options in the binding update. I would go for maximum one. At least
that was my original idea.
Do we have to say "one"? For example, it might be possible to
provide two different services on the same Mobile IP tunnel. We
could leave this up to folks who might use this option.
Vijay
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