Re: [Mip4] Problem of using layer 2 triggers alone for the Low latency Handoff for MIPv4

Hello, Stephane,
                               Thanks for your query.

                                Please note my responses in-line.

Regards,
     Sebastian

ANTOINE Stephane RD-ILAB-LON wrote:

> Hello,
>
> I would like to get some feedback about the problem, as described 
> below, of using layer 2 triggers alone to initiate the Low latency 
> Handoff for MIPv4:
>
>   
>
> The Low Latency Handoff for MIPv4 as described in
>
> http://www.ietf.org/internet-drafts/draft-ietf-mobileip-lowlatency-handoffs-v4-11.txt
>
> assumes availability of the L2 triggers which contain Layer 3 
> information such as the IP address of the new Foreign Agent. 
> Availability of the Layer 3 information is assumed in the Layer 2 
> trigger. However the method by which the Layer 3 information is made 
> available in the Layer 2 trigger has not been specified.
>
st> The specific procedure used to acquire the L3 information, such as 
the IP address of the appropriate access gateway is dependent on the 
access technology over which the low-latency handoff scheme is applied. 
For instance, the radio access point or base station identifier could be 
used to determine the L3 information associated with the radio access 
point or the base station (L2 entities). The L3 information could be 
statically or dynamically configured at the L2 entity based on the 
connectivity to an L3 entity (access gateway).

> Moreover, Layer 2 trigger will actually occur in response or in 
> prevision to certain link events such as the fading of the relative 
> signal noise ratio below a certain level.
>
st> Yes.

> Relying only on link information to initiate a handoff does not 
> generally gather enough information for the Mobile Node to handoff to 
> the most suitable available access network at the most suitable time.
>
st> See the previous response on L3 information acquisition.

>  
>
> Information from layers higher than Layer 2 (that may come from 
> various protocols) can be used as triggers to compensate the 
> insufficiency of using Layer 2 triggers alone for the Low latency 
> Handoff for MIPv4.
>
st> The L2 trigger information is used to assist the upper layer 
protocols, in the case of wireless mobility with minimum latency, and 
not vice-versa. Using access technology specific schemes, the required 
L3 information, such as the serving access gateway IP address can be 
obtained from the L2 trigger information.

>  
>
> I would also appreciate receiving some feedback upon the work 
> presenting scenarios describing how the low latency Handoff for MIPv4 
> is initiated by higher layer triggers.
>
> http://www.ietf.org/internet-drafts/draft-antoine-mip4-lowlatency-handoff-triggers-00.txt
>
>  
>
> Cheers
>
>  
>
> Stephane
>
>  
>