Subject: [NSIS] Suggestions on Multi-homing section of Mobility Draft

From: "Shivanajay Marwaha" <[email-masked]>
Date: Thu, 16 Feb 2006 19:41:23 +0800

Dear Sung-Hyuck, Seong-Ho, Mobility Applicabilty Draft Authors and
other NSIS WG members, 
 
We have been studying the NSIS Mobility Applicability draft
http://www.ietf.org/internet-drafts/draft-ietf-nsis-applicability-mobili
ty-signaling-03.txt and have some suggestions. 
 
Here are few of the Comments/suggestion on section 5 in the NSIS
mobility applicability draft:- (More to follow in the subsequent emails
:)

------------------------------------------------------------
Suggestion 1 -
General introduction of multihoming seems to be lacking
 
Discussion -
In section 5.2, current text lacks a general introduction to
multihoming. The first two sentences talk only about a specific issue
concerning multihomed host. Therefore it would be better to include some
general description of multihoming environment to give readers a
complete picture. In our view, the text from section 5.2.1 of version 02
suits the Purpose better. So, we suggest that the first two sentences of
section 5.2 be replaced with the following text (from section 5.2.1 of
version 02):-
 
Suggested Text -
"Multihoming refers to a situation where an end node has several
parallel communication paths to use.  An end node (e.g., an MN in mobile
environments) may have multiple homogeneous/heterogeneous interfaces.
Multiple interfaces can be used in order to increase bandwidth
availability or to select the most appropriate interface according to
the type of flow or choices of the user [17].
 
Basically, each network interface has different performance, bandwidth,
access range, and reliability.  Users may want to select the most
appropriate set of network interface(s) depending on the network
environment, particularly in wireless networks which are less reliable
than wired networks.  Users may also want to select the most appropriate
interface based on certain criteria or to combine a set of interfaces to
get sufficient bandwidth [17].
 
In multihomed environments, multiple addresses can be allocated to
either a single interface or multiple interfaces to provide ubiquitous
and fault-tolerant access to the Internet.  Other benefits of having
multiple interfaces include load balancing, bi-casting, load sharing,
and etc."
 
------------------------------------------------------------------
 
Suggestion 2 -
 Section 5.2.1, Para below Figure 14: (homogenous interface vs. multiple
interfaces)

Current text: - (Section 5.2.1)
 " We assumed homogeneous wireless interfaces in this draft although
multihoming with multiple interfaces would be more efficient on
heterogeneous interfaces due to the increased path diversity.  The
issues on heterogeneous interfaces are for further study. "

Discussion -
According to the diagram the issue discussed in this section is about
using one connection for communication (although multiple connections
may be available/possible). This does not even depends on the number of
interfaces available on the MN, since in a site multihoming environment,
MN can still have multiple address (in turn multiple connections to CN)
on one interface.  Therefore, the use of "homogeneous" and
"heterogeneous" in the above text does not reflect the actual issue. It
would be better to clarify the difference. 
Furthermore, in section 5.2.5, some discussion was provided about the
case of using mulitple connections. This should be also reflected in the
text. So we suggest to replace the 4th paragraph of section 5.2.1 with
following text:

Suggested Text -
"This section deals with the scenario where only one connection is used
for data traffic at a time. In some case multiple connections via
heterogeneous interfaces may be necessary and more efficient.
Discussion about host multihoming issues is included in section 5.2.5 of
this draft"
 
Regards,
Shivanajay Marwaha
(On Behalf of Takako Sanda, Toyoki Ue and Cheng Hong)

_______________________________________________
nsis mailing list
[email-masked]
https://www1.ietf.org/mailman/listinfo/nsis

---

From: Sung-Hyuck Lee <[email-masked]>
Date: Mon, 20 Feb 2006 19:45:21 +0900

Dear Shivanajay,

Thank you for your interests.
Please refer to my comments in line.

Warm regards,

Sung-Hyuck

----- Original Message ----- 
From: "Shivanajay Marwaha" <[email-masked]>

> Dear Sung-Hyuck, Seong-Ho, Mobility Applicabilty Draft Authors and other
> NSIS WG members, 
>  
> mobility applicability draft:-
> (More to follow in the subsequent emails :)
> 
> concerning multihomed host. Therefore it would be better to include
> some general description of multihoming environment to give readers a
> suits the
> Purpose better. So, we suggest that the first two sentences of section
> 5.2 be
> replaced with the following text (from section 5.2.1 of version 02):-
>  
> Suggested Text - 
> parallel communication paths to use.  An end node (e.g., an MN in  
> mobile environments) may have multiple homogeneous/heterogeneous
> interfaces.  Multiple interfaces can be used in order to increase 
> bandwidth availability or to select the most appropriate interface
> according to the type of flow or choices of the user [17].
>  
> Basically, each network interface has different performance,
> bandwidth, access range, and reliability.  Users may want to select 
> the most appropriate set of network interface(s) depending on the
> network environment, particularly in wireless networks which are less
> reliable than wired networks.  Users may also want to select the most
> appropriate interface based on certain criteria or to combine a set
> of interfaces to get sufficient bandwidth [17].
> 
> either a single interface or multiple interfaces to provide  
> ubiquitous and fault-tolerant access to the Internet.  Other benefits
> of having multiple interfaces include load balancing, bi-casting,
> load sharing, and etc."

[SHL] It is not easy to evaluate which introduction is better because 
we need to consider various views on editing of drafts: The way of 
editing can be different dependent on what preference is, simpler or 
more detailed expression. Till now, the mobility authors have tried to 
make the mobility draft simpler with clearer text. However, the authors 
will refer to your valuable comments.

> may be available/possible). This does not even depends on the number
> of interfaces available on the MN, since in a site multihoming
> environment, MN can still have multiple address (in turn multiple
> connections to CN) on one interface.  Therefore, the use of
> "homogeneous" and "heterogeneous" in the above text does not reflect
> the actual issue. It would be better to clarify the difference. 
> case of using mulitple connections. This should be also reflected in
> the text. So we suggest to replace the 4th paragraph of section 5.2.1
> with
> following text:

[SHL] You seem to misunderstand the terms, "homogeneous" and 
"heterogeneous".  Homogeneous interfaces mean that the interfaces 
consist just same physical air interface, for example, only IEEE 802.11. 
Heterogeneous interfaces mean that the interfaces simultaneously consist 
different physical air interfaces, for example, WIFI and 3G, WIFI and 
WIMAX/WiBro, etc.

> Suggested Text - 
> "This section deals with the scenario where only one connection is
> used for data traffic at a time. In some case multiple connections
> via heterogeneous interfaces may be necessary and more efficient.
> Discussion about host multihoming issues is included in section 5.2.5
> of this draft"
> 
> Regards,
> Shivanajay Marwaha

---

From: Sung-Hyuck Lee <[email-masked]>
Date: Mon, 20 Feb 2006 20:47:22 +0900

Hi Cheng,

----- Original Message ----- 
From: "Cheng Hong" <[email-masked]>
To: "Sung-Hyuck Lee" <[email-masked]>; "Shivanajay Marwaha" <[email-masked]>; <[email-masked]>
Cc: "Takako Sanda" <[email-masked]>; "Toyoki Ue" <[email-masked]>; "Pek Yew Tan" <[email-masked]>; "Seong-Ho Jeong" <[email-masked]>; "Xiaoming Fu" <[email-masked]>; "Hannes Tschofenig" <[email-masked]>; "Jukka MJ Manner" <[email-masked]>
Sent: Monday, February 20, 2006 7:57 PM
Subject: RE: Suggestions on Multi-homing section of Mobility Draft

> Hi Sung-Hyuck,
>
> Thanks a lot for your reply. Since Shivanajay is on leave today, I would
> like to repond one of the comment for him:
> 
> That is exactly the point Shiv wants to make. Having "homogeneous"
> interface does not necessary mean that only one connection is being used
> at one time (which is what section 5.2.1 is discussing about: selecting
> the best connection for communication). 

[SHL] Selecting the best connection is just one example which shows the use 
case for multihoming in NSIS scenarios.
 
> It is possible for the terminal to have multiple "homogeneous"
> interface, e.g. my laptop can have two wireless LAN connections (one
> through integrated card -- thanks to Centreno :), one through external
> card). 
>
> Also, it is possible for a terminal with a single "homogeneous"
> interface to have multiple addresses in a site multihoming environment,
> e.g. several prefixs are offered. 

[SHL] Yes.
 
> Therefore, we think that it would be better to avoid use of the
> "homogeneous" to describe the problem discussed in section 5.2.1.

[SHL] The use of terms, "homogeneous" and "heterogeneous" is needed to
identify the differences between multihoming scenarios in homogeneous and 
heterogeneous environments. That is why the terms were used in the mobility 
draft.

Warm regards,

Sung-Hyuck

> -----Original Message-----
> From: Sung-Hyuck Lee [mailto:[email-masked]] 
> Sent: Monday, February 20, 2006 6:43 PM
> To: Shivanajay Marwaha; [email-masked]
> Cc: Takako Sanda; Toyoki Ue; Cheng Hong; Pek Yew Tan; 
> Seong-Ho Jeong; 'Xiaoming Fu'; 'Hannes Tschofenig'; 'Jukka MJ Manner'
> Subject: Re: Suggestions on Multi-homing section of Mobility Draft
> 
> Dear Shivanajay,
>