Subject: Re: [mobile-ip] MobileIPv6 VS DNS

From: "Jaehoon Jeong" <[email-masked]>
Date: Thu, 13 Mar 2003 11:56:16 +0900

[mobile-ip] MobileIPv6 VS DNSHello, I am the author of this draft.
http://www.ietf.org/internet-drafts/draft-jeong-hmipv6-dns-optimization-00.txt 
(Title : The Autoconfiguration of Recursive DNS Server and 
 the Optimization of DNS Name Resolution in Hierarchical Mobile IPv6)
This draft is one of RA-based DNS discovery solutions.

>----- Original Message ----- 
>From: Warodom Werapun 
>To: [email-masked] 
>Sent: Monday, March 10, 2003 7:19 PM
>Subject: [mobile-ip] MobileIPv6 VS DNS

>Following this link: 
>http://www.ietf.org/internet-drafts/draft-jeong-hmipv6-dns-optimization-00.txt 
>When mobile node move, we only map to new DNS server. 

  When mobile node moves into another MAP domain in hierarchical mobile IPv6 network, 
  it needs to find a new recursive DNS server  for the optimization of DNS resolution process 
  in the respect of name resolution time.

>We can reach mobile node in new location by using name in DNS. 

  Yes, your're right. But when a mobile node tries to connect to an Internet service, such as web server,
  first of all, it should resolve the service's DNS name into IP address.
  In current DNS operation, the mobile node uses a fixed recursive DNS server normally placed in its home network.
  If the mobile node can find a new recursive DNS server in the visited network, 
  it can use the new one for DNS name resolution instead of the previous one.
  In the result, the time for name resolution can be saved. This is the main object of this draft.
  I think the idea of the draft can be applied to IPv6 or mobile IPv6 network as well as hierarchical mobile IPv6 network.

>So, we don't need to set up any Home agent, are we? 
>/Warodom 
>Ps: I'm so newbies in MIPv6. 
>  Thank you for your reply. 

Thanks for your question.

Regards,
Jaehoon

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---

From: [email-masked]
Date: Sat, 15 Mar 2003 09:31:31 +0900

Hi, Warodom.

I'll answer your question as inline.

From: Warodom Werapun[[email-masked]]
To: Jaehoon Jeong
Sent: Re: [mobile-ip] MobileIPv6 VS DNS
Date: 2003/03/15 Sat 01:43

	 I thought, we could use DHCPv6 [if it has] do same processing with 
your draft-propose,are we? 
==> yes, you're right.
How about performance of use DHPCv6 VS your draft?
==> I think my solution is better and more suitable to HMIPv6 in the
respect of the resolution time.
==> If we use DHCPv6, our mobile nodes should send DHCP request message to
get the information
==> of recursive DNS server. But when we use my solution, we need not to
send a request message, 
==> because our mobile nodes get MAP option message with recursive DNS
server's address in a new MAP domain.

==> Jaehoon

- Warodom
>  In current DNS operation, the mobile node uses a fixed recursive DNS
server normally placed in its home network. 
>  I think the idea of the draft can be applied to IPv6 or mobile IPv6
network as well as hierarchical mobile IPv6 network.

---

From: [email-masked]
Date: Sat, 15 Mar 2003 09:50:36 +0900

inline..

From: Warodom Werapun[[email-masked]]
To: Jaehoon Jeong
Cc:[email-masked]; DNSOP WG
Subject: Re: [mobile-ip] MobileIPv6 VS DNS
Date: 2003/03/15 Sat 02:15

If we have change DNS Server IP with Anycast IP address.[in the future] 
Then, MN doesn't need to configure any DNS IP address. 
==> In the past, IPv6 wg tried to use anycast for DNS server discovery, 
==> but because anycast has some problems, they gave up that approach.
==> Please look at the draft, http://www.ietf.org/internet-drafts/draft-
ietf-ipv6-dns-discovery-07.txt,
==>to see the problem of anycast. The related paragraph is as follows;
----------------------------------------------------------------------------
---------------------------------
...
  On top of the classic problems (TCP sessions, ICMP messages,...) using
   an anycast address would hide the real locations of the recursive DNS
   servers to the stub resolver, prohibiting it to keep track of which
   servers are performing correctly. 
...
----------------------------------------------------------------------------
---------------------------------
==> This draft suggests a new approach in use of well-known site-local
addresses for recursive DNS server.

But one problem remain, some networks can't use same network prefix. 
    
How do you think about this solution?
==> I think the approach of site-local address is better than that of
anycast. 
==> But the limitation of site-local address approach is that all the
networks should run recursive DNS server with
==> well-known site-local address(es) for recursive DNS server(s) in the
managed network.
==> Thanks for your suggestion.

==> /Jaehoon
Regards, 
- Warodom