Subject: comments on shirasaki-dualstack-service-00

From: Pekka Savola <[email-masked]>
Date: Sun, 16 Mar 2003 13:44:54 +0200 (EET)

Hi,

(It's amazing how many drafts you can read on a 12h flight.. :-)

Thanks for documenting the NTT DSL access service.  I think this is very 
useful.  A few comments, mostly editorial in nature, below.

non-editorial:
--------------

2. Requirements

   The keywords MUST, MUST NOT, REQUIRED, SHALL, SHALL NOT, SHOULD,
   SHOULD NOT, RECOMMENDED, MAY, and OPTIONAL, when they appear in this
   document, are to be interpreted as described in [RFC2119].

==> I'd remove this section completely and switch to lower case must,
should, etc. because this isn't exactly a document with interop interest :-)

   When CPE receives packets which are destined for the delegated
   prefix, CPE MUST NOT forward the packets to a PE. CPE SHOULD return
   ICMPv6 Destination Unreachable message to a source address or
   silently discard the packets.

==> would it be worthwhile to describe how this is accomplished?  Null0
route is at least trivial, but it won't return an unreachable message
except by explicit config in some implementations.  But maybe this is
outside of scope..

editorial:
----------

INTERNET-DRAFT                                        Yasuhiro Shirasaki
Expires: August, 2003                                      Shin Miyakawa
                                                      Toshiyuki Yamasaki
                                                        Ayako Takenouchi
==> initial of the first name only

   service should have mechanism to configure IPv6 specific parameters
==> s/service/services/

   Here are some antecedents of the architecture.  The architecture
   mainly targets at a leased line ADSL service for home users. It
==> s/mainly targets/is mainly targeted/
   assumes that there is a PPP logical link between CPE and Provider
==> spell out PPP

   follows.

  o  IPv6 and IPv4 connectivity are provided over a single PPP logical
     link.

 ==> bullets are one character left of the normal intendation, shit a few
chars right?

  o  IPv6 connectivity is independent of IPv4 connectivity.  IPV6CP and
     IPCP works independently over a single PPP logical link.
==> s/works/work/

   The automatic configuration function aims at simplication of user
==> s/cation/fication/

   setup.  Usually, users have to configure at least two IPv6 specific
   parameters, prefix(es) and IPv6 DNS servers addresses. The function
==> s/servers/servers'/ (if this was the intent)

   In this section, details of the user network interface specification
   are described. Only PPPoE and its upper layer are mentioned. The
==> spell out PPPoE
   other layers such as ethernet and lowers are out of scope.  IPv4
==> s/eth/Eth/

   The service uses PPP connection and CHAP authentication to identify
==> spell out CHAP.

   without any side-effect for each other. It is intended that users can
   choose three services, IPv4 only, IPv6 only and IPv4/IPv6 dual stack.
==> s/choose/choose between/ ?

   CPE MUST reply with LCP Echo-Reply when it is in the LCP Opened state
   and receives LCP Echo-Request as described in [RFC1661]
==> s/]/]./

3.3. Prefix Delegation

   PE delegates prefixes to CPE by DHCPv6 [DHCPv6] with prefix
   delegation options [PD]. The model of sequence for prefix delegation
   is as follows:

==> perhaps could use like "a DHCPv6 Solicit", "an IA_PD options" etc. more
in this section (rather than without a/an/the)

  o  A CPE requests prefixes to a PE by sending DHCPv6 Solicit message
==> s/to/from/

  o  The PE chooses prefix(es) which is notified by AAA server or
     choosen from PE's local pool and returns Advertise message which
     contains IA_PD and IA_PD Prefix option.  The prefix-length in the
     IA_PD Prefix option is 48.

==> reword" which is notified by AAA server"
==> s/choosen/chosen/
==> s/contains ... option/contain ... options/

   Once IPV6CP is terminated or restarted by any reason, CPE MUST
   initiate a Rebind/Reply message exchange as described in [PD].
==> s/Once/If/ ?

3.4. Address Assignment

   The CPE assigns global-scope prefixes subnetted from the delegated
   prefix to its downstream interfaces with its length /64.  Because

==> s|prefixes .. with its length /64|/64 prefixes .../

3.6. Obtaining Addresses of DNS Servers

   The service provides IPv6 DNS cache servers in the ISP site as same
   as IPv4 case. PE notifies the global unicast addresses of these
==> reword "as same as IPv4 case"

3.7. Miscellaneous Information

   PE may notify other IPv6 enabled server addresses such as Network
   Time Protocol servers [OPT-NTP], SIP servers [OPT-SIP], etc in
   Advertise/Reply message on the prefix delegation message exchange if
   it is available.
==> s/it is/those are/

   packet when it receives ICMPv6 Echo Request packet. The health check
   packets are destined for subnet-rouer anycast address for the
   delegated prefix.
==> s/for/to/, s/rouer/router

[RFC2472]
     D. Haskin and E. Allen, "IP Version 6 over PPP", RFC 2472, December
     1998.
==> author's surname should be listed first, same in some other refs.

Author's Address
==> s/Author's Address/Authors' Addresses/

-- 
Pekka Savola                 "You each name yourselves king, yet the
Netcore Oy                    kingdom bleeds."
Systems. Networks. Security. -- George R.R. Martin: A Clash of Kings

---

From: SHIRASAKI Yasuhiro <[email-masked]>
Date: Tue, 18 Mar 2003 09:32:31 +0900 (JST)

Hi Pekka,

> should, etc. because this isn't exactly a document with interop interest :-)

agree. I'll remove it.

> except by explicit config in some implementations.  But maybe this is

I've imagined reject route behavior of KAME stack first at that time.

Anyway, thank you for your comments. I'll update the draft.

--
SHIRASAKI Yasuhiro @ NTT Communications