Subject: [mif] FW: I-D Action:draft-hong-mif-virtual-interface-00.txt

From: "Yong-Geun Hong" <[email-masked]>
Date: Mon, 2 Mar 2009 15:35:14 +0900

Hi, all.

We submit another draft "Virtual network interface model for multiple
network interfaces in a host ".

Please review and comment on it.

Best regards.

Yong-Geun.

-----Original Message-----
From: [email-masked] [mailto:[email-masked]]
On Behalf Of [email-masked]
Sent: Monday, March 02, 2009 2:00 PM
To: [email-masked]
Subject: I-D Action:draft-hong-mif-virtual-interface-00.txt 

A New Internet-Draft is available from the on-line Internet-Drafts
directories.

	Title           : Virtual network interface model for multiple
network interfaces in a host
	Author(s)       : Y. Hong, J. Youn
	Filename        : draft-hong-mif-virtual-interface-00.txt
	Pages           : 7
	Date            : 2009-03-01

The use of multiple interfaces in a host with existing TCP/IP stack may
have some problems.  This document discusses how to solve the problems of
multiple interfaces in a host and proposes a virtual network interface
model which describes the use of original TCP/IP stack to support multiple
network interfaces in a host.

A URL for this Internet-Draft is:
http://www.ietf.org/internet-drafts/draft-hong-mif-virtual-interface-00.txt

Internet-Drafts are also available by anonymous FTP at:
ftp://ftp.ietf.org/internet-drafts/

Below is the data which will enable a MIME compliant mail reader
implementation to automatically retrieve the ASCII version of the Internet-
Draft.
[InternetShortcut]
URL=ftp://ftp.ietf.org/internet-drafts/draft-hong-mif-virtual-interface-00.txt

---

From: <[email-masked]>
Date: Mon, 2 Mar 2009 22:08:14 +0100

Hi,

To clarify, does this propose to use virtual interface when host either has same IP address(es) configured for physical interfaces (e.g. with help of netlmm) or when host is utilizing mobile IP (e.g. DSMIP6)? And for such hosts the draft proposes that connection manager chooses which physical interface shall be used for outbound traffic?

And am I correct that the virtual interface is not to be used when host does not have mobile IP and when physical interfaces happen to have different IP addresses?

Best regards,

	Teemu 

>From: [email-masked] [mailto:[email-masked]] On 
>Behalf Of ext Yong-Geun Hong
>Sent: 02 March, 2009 08:35
>To: [email-masked]
>Subject: [mif] FW: I-D Action:draft-hong-mif-virtual-interface-00.txt
>
>Hi, all.
>
>We submit another draft "Virtual network interface model for 
>multiple network interfaces in a host ".
>
>A New Internet-Draft is available from the on-line 
>Internet-Drafts directories.
>
>The use of multiple interfaces in a host with existing TCP/IP 
>stack may have some problems.  This document discusses how to 
>solve the problems of multiple interfaces in a host and 
>proposes a virtual network interface model which describes the 
>use of original TCP/IP stack to support multiple network 
>interfaces in a host.
>
>Below is the data which will enable a MIME compliant mail 
>reader implementation to automatically retrieve the ASCII 
>version of the Internet- Draft.
>

---

From: "Yong-Geun Hong" <[email-masked]>
Date: Tue, 3 Mar 2009 10:58:32 +0900

Hi, Teemu.

See reply inline.

> From: [email-masked] [mailto:[email-masked]]
> Sent: Tuesday, March 03, 2009 6:08 AM
> To: [email-masked]; [email-masked]
> Subject: RE: [mif] FW: I-D Action:draft-hong-mif-virtual-interface-00.txt
> 
> Hi,
> 
> To clarify, does this propose to use virtual interface when host either
> has same IP address(es) configured for physical interfaces (e.g. with help
> of netlmm) or when host is utilizing mobile IP (e.g. DSMIP6)?

  => When we implement the virtual interface, each physical network
interfaces
   are connected to different access networks (one is CDMA network and the
other is
   WLAN network) and the configured IP address of each physical network
interfaces
   is different. (because the operator of CDMA is different to WLAN)

   If session continuity is important, then we used Mobile IPv6 (RFC 3775
based)
   HoA is mapped to the virtual interface and CoA is mapped to the physical
network interface.

   But, if session continuity is not important, then one of IP addresses of
the physical
  network interfaces can be mapped to the virtual interface.

 And for such
> hosts the draft proposes that connection manager chooses which physical
> interface shall be used for outbound traffic?

  => Yes.
  
> 
> And am I correct that the virtual interface is not to be used when host
> does not have mobile IP and when physical interfaces happen to have
> different IP addresses?

  => No, as I said in first answer, it depends on the requirement of
session continuity. 
      If session continuity is needed, virtual interface can be helped from
other mobility protocol.

 Best regards.

 Yong-Geun.

---

From: <[email-masked]>
Date: Tue, 3 Mar 2009 06:00:19 +0100

Hi,

Thanks for your quick reply, inline 

>From: ext Yong-Geun Hong [mailto:[email-masked]] 
>Sent: 03 March, 2009 03:59
>To: Savolainen Teemu (Nokia-D-MSW/Tampere); [email-masked]
>Subject: RE: [mif] FW: I-D 
>Action:draft-hong-mif-virtual-interface-00.txt
>
>   But, if session continuity is not important, then one of IP 
>addresses of the physical

This is good clarification I don't recall seeing in the draft? If so, would be good to have there.

Does it then also mean then that the IP addresses of another physical interfaces cannot be used for IP communication at the same time - or would the apps bypass the virtual interface in that case and directly use the physical interface?

Best regards,

	Teemu

---

From: Scott Brim <[email-masked]>
Date: Tue, 3 Mar 2009 07:07:43 +0100

> http://www.ietf.org/internet-drafts/draft-hong-mif-virtual-interface-00.txt

Could you compare this to ...

- shim6?  Shim6 presents a single IP address to the layers above and
  manages multiple interfaces.  It is well-developed.

- hip?  HIP presents a "virtual" interface address to upper layers
  while being able to send data packets over any src/dst pair.

- SCTP?  etc.

- Trilogy "resource pooling" transport?  I don't have any pointers to
  text but

  http://www.ietf.org/proceedings/08jul/slides/tsvarea-2.pdf
  https://fit.nokia.com/lars/talks/2008-ccw-trilogy.pdf

  Trilogy transport proposes to use multiple interfaces for data all
  of the time.  One of the interesting questions is how to balance
  traffic across src/dst pairs.

Thank you ... Scott

---

From: "Yong-Geun Hong" <[email-masked]>
Date: Tue, 3 Mar 2009 15:57:49 +0900

Hi, Teemu.

Thanks for your comments.

See reply inline. 

> Sent: Tuesday, March 03, 2009 2:00 PM
> Does it then also mean then that the IP addresses of another physical
> interfaces cannot be used for IP communication at the same time - or would
> the apps bypass the virtual interface in that case and directly use the
> physical interface?

 => Because the virtual interface model is designed for the host with
multiple 
    interfaces but none layer do not support (This is described in section
3.1 of
    "Analysis and scenarios of multiple interfaces in a host",
    http://www.ietf.org/internet-drafts/draft-hong-mif-analysis-scenario-00.
txt),
    using original TCP/IP stack is an important key. 

    So, in current virtual interface model, IP addresses of another physical
    interfaces cannot be used for IP communication at the same time. 
    (If applications bypass the virtual interface in that case and directly
use the 
     physical interface, it is needed to modify applications to support
this feature.)

    We know that this situation may limit the simultaneous usage of
multiple interfaces.
    To support simultaneous usage of multiple interfaces in the virtual
interface model, 
    I think that we can do some needed job (e.g., enhance the connection
manager to do)

    Best regards.

    Yong-Geun.

---

From: "Yong-Geun Hong" <[email-masked]>
Date: Tue, 3 Mar 2009 17:10:25 +0900

Hi, Scott.

I try to answer your question.

See inline. 

> From: [email-masked] [mailto:[email-masked]] On Behalf Of
> Scott Brim
> Sent: Tuesday, March 03, 2009 3:08 PM
> To: [email-masked]
> Subject: Re: [mif] FW: I-D Action:draft-hong-mif-virtual-interface-00.txt
> 
    => IMHO, shim6 and hip are for site multi-homing not host's multiple
interfaces.
        (I think that this issue is well described in the following
documents)
       http://www.ietf.org/internet-drafts/draft-hui-ip-multiple-
connections-ps-01.txt
       http://www.ietf.org/internet-drafts/draft-yang-mif-req-00.txt

        BTW, The virtual interface model is for multiple interfaces in a
host without modifying
       TCP/IP stack and it is located below network layer.

> - SCTP?  etc.
    => As far as I know, I understand that SCTP provide multi-homing and
multi-streaming at 
       transport layer. So, it is not directly related to multiple
interfaces in a host. 
  
>   traffic across src/dst pairs.

    => To support multiple interfaces in a host, there may be various ways
to do.
        I understand that Trilogy transport can provide multi-path
communication at transport layer
        with the help of multiple interfaces. So, this scenario could be in
the section 3.3 Multiple
        interfaces and network layer and transport layer support in
"Analysis and scenarios of
        multiple interfaces in a host",  http://www.ietf.org/internet-
drafts/draft-hong-mif-analysis-scenario-00.txt),

    => But, the virtual interface model is for the host with multiple
interfaces but none layer do 
        not support (This is described in section 3.1 of "Analysis and
scenarios of multiple interfaces in a host")

    Best regards.

    Yong-Geun.

> 
> Thank you ... Scott
> _______________________________________________
> mif mailing list
> [email-masked]
> https://www.ietf.org/mailman/listinfo/mif

---

From: Jari Arkko <[email-masked]>
Date: Tue, 03 Mar 2009 09:21:33 +0100

Yong-Geun, Scott,

>     => IMHO, shim6 and hip are for site multi-homing not host's multiple

I don't think this is true.

However, a better distinction may be that Shim6 and Hip both assume 
either the peer or some network "proxy" agent is there to talk the 
Shim6/Hip with the host. My understanding is that MIF assumes it is 
simply talking with plain old peers in the Internet, and has to cope 
without any e2e protocol changes.

Jari

---

From: George Tsirtsis <[email-masked]>
Date: Tue, 3 Mar 2009 08:32:19 +0000

Hi Yong-Geun,

I wonder whether this is the right place to start from.

In this draft you assume that the host stack cannot handle multiple
interfaces and you proceed to add a virtual interface and presumably
some functionality to deal with this transparently from the rest of
the stack.

While this might have a place in the Internet Universe, I think a
potential IETF WG should be more ambitious. The "real" work to be done
is to define how an IP stack should behave in the presence of multiple
Interfaces without the need of hiding them under the carpet. This
could be done mainly by extending the host requirements document.

As an analogy,  what you seem to be  doing here with the virtual
interface, is equivalent to the early IPv6 designers deciding to first
of all design "Bump in the Stack" as opposed to defining how a host
IPv6 stack should look like. Of course a Bump in the Stack, as well as
your virtual interface are both implementation short-cuts and not the
real think.

My 2 pence
George