Subject: [NSIS] a scenario for QoS signaling in Mobile IP

From: Xiaoming Fu <[email-masked]>
Date: Thu, 08 Nov 2001 18:17:58 +0100

Hi,

I would like to point out some problems in the following scenario:
Consider the case when a MN moves to an area where multiple radio
technologies/access points(or say, ARs) overlap:

- it may be desired for the mobile user to choose a good AR from all
these candidate ARs, in such a way that the path via this new AR can 
support a satisfying/better QoS than the currently used one.

Here a QoS signaling protocol may be desired to provide such a
capability (possibly by negotiating with the ARs/access networks or
communicating with MIP protocols).

- If the path via a new AR could not accommodate the QoS requirement 
at all, either an alternative AR or decreased QoS reservation should 
be acceptable. As the resources in wireless radio networks are very
precious, it is desirable that there is some kind of QoS negotiation 
in the end system cooperating with the QoS signaling protocol or be 
able to specify a more flexible (ranged) QoS requirement. 

I find neither of these requirements as above is listed in the 
mip-qos-requirement draft. Nevertheless, this is definitely important 
in a mobile scenario. As this may be useful for general QoS 
signaling, I would like to propose it here.

Regards,
Xiaoming

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From: "Zheng Haihong (NRC/Dallas)" <[email-masked]>
Date: Thu, 8 Nov 2001 14:14:19 -0600

Hi, Xiaoming, 

> -----Original Message-----
> From: ext Xiaoming Fu [mailto:[email-masked]]
> Sent: 08 November, 2001 11:18 AM
> To: NSIS
> Subject: [NSIS] a scenario for QoS signaling in Mobile IP
> 
> 
> Hi,
> 

To make this requirement more generic, I would say it is the signaling
capability of modifying an existing QoS. Basically whenever a MN sees
the needs to change the QoS requirement either based on application
request or change of network connection type, it can signal the request
to modify the QoS it requested before. On the other hand, the network
should also have the similar capability to request or indicate the
change of QoS to MN.  

> able to specify a more flexible (ranged) QoS requirement. 

In cellular network, there is a concept of QoS profile. Based on
resource availability, the network can downgrade the QoS for the MN
based on profile. The same scheme can be applied here by either using
profile concept or specifying a wider range QoS requirement as you said
before. Of course the network should also signal the change of QoS to
the MN so that the application layer in MN can adjust its traffic
behavior. 

> signaling, I would like to propose it here.

Since we are talking about signaling requirement in NSIS, we should
focus on signaling. Thus, the requirement here could be the signaling
capability for QoS modification from both MN and network. 

BR,

Haihong

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From: Xiaoming Fu <[email-masked]>
Date: Thu, 8 Nov 2001 13:35:34 -0800 (PST)

Hi Haihong,

> should also have the similar capability to request or indicate the

What I tried point out here is a QoS signaling solution (perhaps
cooperating with other schemes) should be able to find an AR fulfiling
satisfying/better QoS. I believe the network-initiated or
end-system-initiated QoS negotiation is also important, as we discussed
below. 

> the MN so that the application layer in MN can adjust its traffic

Exactly! QoS profile is very useful for this purpose.

Regards,
Xiaoming

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From: [email-masked]
Date: Fri, 9 Nov 2001 11:11:14 +0200

Hi Karl,

> From: ext Holger Karl [mailto:[email-masked]]
> Sent: 09 November, 2001 10:58
> Cc: [email-masked]
> Subject: Re: [NSIS] a scenario for QoS signaling in Mobile IP
> 
> 
> Hello John,
> 
> 
> [email-masked] wrote:
> > 
> > to find an AR which best meets is QoS needs.  I don't
> > think it is reasonable to suggest anything more, as it
> > could be considered as opening the possibility of a Denial
> > of Service attack if the QoS signaling protocol would be
> > enabled to use more QoS resources than it is authorized for.
> > 
> 
> This is definitely true. Shouldn't there be some 
> considerations that QoS signaling needs to go hand-in-hand 
> with authorization protocols?

Yes, and the current charter mentions it:

 As with nearly all work being done in the IETF, security is a 
 very important concern for NSIS.  The working group will study 
 the security requirements for QoS Signaling, as well as create a 
 threat analysis of QoS signaling. Compatibility with authentication 
 and authorization mechanisms is also a concern.  These topics will 
 be addressed in the Signaling Requirements document.

John