Subject: [dhcwg] additional option for dhcpv6

From: Vijay Bhaskar A K <[email-masked]>
Date: Sat, 19 Jan 2002 02:22:01 +0530 (IST)

I have  completed the text for the  additional  options  which are worth
adding.  Please go through it and tell me your comments

~ Vijay

- Network Time Protocol Server Option

This option  provides a list of one or more IP  addresses of NTP servers
available  to the  client.  NTP  Servers  SHOULD  be listed  in order of
preference.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      OPTION_NTP_SERVERS       |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                   NTP server (IP address)                     |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                   NTP server (IP address)                     |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          OPTION_NTP_SERVERS (TBD)

      option-len           See section 22.

      NTP server           IPv6 address of a NTP server available to 
                           the client.

- Network Information Service (NIS) Servers Option

This option  provides a list of one or more IP  addresses of NIS servers
available  to the  client.  NIS  Servers  SHOULD  be listed  in order of
preference.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |      OPTION_NIS_SERVERS       |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                   NIS server (IP address)                     |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                   NIS server (IP address)                     |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          OPTION_NIS_SERVERS (TBD)

      option-len           See section 22.

      NIS server           IPv6 address of a NIS server available to 
                           the client.

- Network Information Service V2 (NIS+) Servers Option

This option  provides a list of one or more IP addresses of NIS+ servers
available  to the  client.  NIS+  Servers  SHOULD be listed  in order of
preference.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |     OPTION_NISP_SERVERS       |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                  NIS+ server (IP address)                     |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                  NIS+ server (IP address)                     |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                              ...                              |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          OPTION_NISP_SERVERS (TBD)

      option-len           See section 22.

      NIS+ server          IPv6 address of a NSI+ server available to 
                           the client.

- FQDN Option

This  option  specifies  the name of the  client.  The  name  should  be
qualified  with the  local  domain  name.  See [15]  for  character  set
restrictions.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        OPTION_FQDN            |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                            FQDN                               |
   |                            ...                                |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          TBD

      option-len           See section 22.

      FQDN                 The FQDN of the client 

If there is a FQDN associated with a temporary  address  assigned to the
IA, then this  option  is  encapsulated  inside  the IA  address  option
associated  with the temporary  address.  It can occur as an independent
option, if the FQDN denotes the host itself.

- Static Route Option

This option  specifies a list of static  routes  that the client  should
install  in  its  routing   cache.  If  multiple   routes  to  the  same
destination  are  specified,  they are  listed  in  descending  order of
priority.

The routes consist of a list of IP address  pairs.  The first address is
the  destination  address, and the second  address is the router for the
destination.

    0                   1                   2                   3 
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |          OPTION_ROUTES        |             option-len        | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |    prefix-len   |                                             | 
   +-+-+-+-+-+-+-+-+-+                                             | 
   |                                                               | 
   |             destination prefix address (n bytes)              | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                    destination address                        |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    prefix-len   |                                             | 
   +-+-+-+-+-+-+-+-+-+                                             | 
   |                                                               | 
   |             destination prefix address (n bytes)              | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                      router address                           |
   |                                                               |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        ...                                    |

      option-code          TBD

      option-len           See section 22.

      prefix-len           prefix length of the destination subnet.

      destination          The subnet prefix of the destination subnet.
      prefix address       Its length is <n> byte, Where <n> is the minimum 
			   number of bytes required to represent <prefix-len> 
			   bits of the destination prefix address.

      router address       The router address for reaching the destination
                           subnet.

- Subnet Selection Option

This  option  allows the DHCP  client to specify  the subnet on which to
allocate an address.  This option takes precedence over the methods that
the DHCP  server  uses to  determine  the  subnet on which to  select an
address.

    0                   1                   2                   3 
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |       OPTION_SUBNET_SELECT    |             option-len        | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |    prefix-len   |                                             | 
   +-+-+-+-+-+-+-+-+-+                                             | 
   |                                                               | 
   |                 subnet prefix  (n bytes)                      | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
      
      option-code          TBD

      option-len           See section 22.

      prefix-len           prefix length of the subnet on which the 
                           client wants the server to allocate address.

      subnet prefix        prefix of the subnet on which the client wants
                           the server to allocate address. Its length is 
			   <n> byte, Where <n> is the minimum number of 
			   bytes required to represent <prefix-len> bits 
			   of the subnet prefix.

- Network Information Service (NIS) Domain Name Option

This option  specifies  the name of the client's NIS domain.  The domain
is formatted as a character  string  consisting  of characters  from the
NVT-ASCII  character set.  The minimum length for this option is 1.  See
[15] for character set restrictions.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        OPTION_NIS_DN          |         option-len            |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                     NIS Domain Name                           |
   |                          ...                                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          TBD

      option-len           See section 22.
  
      NIS Domain Name      The name of the client's NIS domain.

- Network Information Service V2 (NIS+) Domain Option

This option  specifies the name of the client's NIS+ domain.  The domain
is formatted as a character  string  consisting  of characters  from the
NVT-ASCII  character set.  The minimum length for this option is 1.  See
[15] for character set restrictions.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        OPTION_NISP_DN          |         option-len           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                     NIS+ Domain Name                          |
   |                          ...                                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          TBD

      option-len           See section 22.
  
      NIS+ Domain Name      The name of the client's NIS+ domain.

- IEEE 1003.1 POSIX Timezone Option

This option  allows  delivery of timezone  information  in the form of a
IEEE 1003.1 POSIX Timezone specifier.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        OPTION_NISP_DN          |         option-len           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |              IEEE 1003.1 POSIX Timezone string                |
   |                          ...                                  |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

      option-code          TBD

      option-len           See section 22.

      Timezone string      Timezone  information  in the form of a
                           IEEE 1003.1 POSIX Timezone specifier.

- Service Location Protocol Directory Agent Option

The Directory Agent option specifies a one or more Directory Agents (DA),
along with zero or more scopes supported by the DAs.

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         OPTION_SLP_DA         |          option-len           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |    typed-scope-list-len       |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               | 
   |                                                               | 
   |                        SLP DA Address                         | 
   |                                                               | 
   |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                               |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
   |                                                               | 
   |                      Typed Scope list                         | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    typed-scope-list-len       |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               | 
   |                                                               | 
   |                        SLP DA Address                         | 
   |                                                               | 
   |                               +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |                               |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               |
   |                                                               | 
   |                      Typed Scope list                         | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        ...                                    |

      option-code            TBD

      option-len             See section 22.

      typed-scope-list-len   Length of the typed scope list.

      SLP DA Address         IP address of the Directory Agent.
 
      Typed Scope list       The string denoting the typed-scope-list 
                             formatted as per RFC 2608 and RFC 2609

- Service Location Protocol Service Scope Option

This option indicates scopes that should be used by a Service Agent (SA)
as described in RFC 2165, when responding to Service Request messages as
specified by the Service Location Protocol (SLP).

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         OPTION_SLP_DA         |          option-len           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ 
   |    typed-scope-list-len       |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               | 
   |                                                               | 
   |                      Typed Scope list                         | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |    typed-scope-list-len       |                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+                               | 
   |                                                               | 
   |                      Typed Scope list                         | 
   |                                                               | 
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                        ...                                    |

      option-code            TBD

      option-len             See section 22.

      typed-scope-list-len   Length of the typed scope list.

      Typed Scope list       specifies the scope that should be used by a 
			     Service Agent (SA) as described in RFC 2165, 
			     when responding to Service Request messages.
                             This should be formatted as per RFC 2608 
			     and RFC 2609

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---

From: Ted Lemon <[email-masked]>
Date: Fri, 18 Jan 2002 15:41:09 -0600

I don't think we need the subnet selection option anymore.   The DHCPv6 
server sends relay-reply messages to the IP source address from which it 
received the relay-forward message, so the relay-provided prefix doesn't 
have to even be a valid IP address, much less one of the relay agent's IP 
addresses.   It just has to represent a valid prefix on the link to which 
the client is attached, which is what the subnet selection option is.

---

From: Mark Stapp <[email-masked]>
Date: Fri, 18 Jan 2002 17:07:29 -0500

Vijay,
Thanks for putting this list together. I have a couple of observations.

1) The FQDN option needs, I think, to look a lot like the FQDN option for 
dhcpv4. The name encoding must be specified. There needs to be 
specification about hosts who do not initially know their entire fqdn. 
There needs to be a way to communicate about which party (if any) will be 
updating DNS. It's probably on my plate to produce that, actually.

2) The subnet-selection option text should not compel the server to somehow 
obey the client's suggestion. It should be explict that the server 
administrator's configuration takes precedence, and that the client's 
indication that it desires a specific subnet can only be a hint that's 
considered along with all of the other information available to the server.

A nit: isn't the option-len sufficient to determine the prefix length? Is 
the prefix-len byte necessary?

3) The encoding for the domain names in the NIS and NIS+ Domain Name 
options should be DNS encoding, shouldn't it? That seems more robust than 
ASCII to me.

4) The 'Service Location Protocol Directory Agent Option' places the 
'typed-scope-list-len' field before the 'DA address', rather than before 
the 'typed scope list'. Couldn't the length of the list immediately precede 
the list?

-- Mark

---

From: Vijay Bhaskar A K <[email-masked]>
Date: Sun, 20 Jan 2002 20:04:24 +0530 (IST)

Mark,

Thanks for your thorough review. See my comments inline.

~ Vijay

> dhcpv4. 

The option i defined here is, for just  transfering the FQDN releated to
temporary  address.  It is  similar  to  hostname  option in  DHCPv4.  I
will rename it to hostname  option.  I feel like, since the DDNS updates
are still TBD, we can define the FQDN  option  with  appropriate  fields
needed later, once DDNS specs are finalised.

> The name encoding must be specified. 

Yes. It is needed. I will add the appropriate text.

> There needs to be 

For the  temporary  addresses,  DNS update is done by server.  So, these
fields are not necessary.

> considered along with all of the other information available to the server.

This is the only way the client can tell its  prefernce  for the prefix.
If the server is not supposed to allocate  address for that prefix, then
it wont.  If the  client is not very  particular  about the  prefix,  it
should not use this  option.  This  option  will be more  helpful in the
network with two prefixes and the client wants a particular one.

> the prefix-len byte necessary?

No, it is not sufficient.  Without the prefix-len field, you cannot find
out the exact prefix length.  For example, you can identify  whether the
prefix  length  is  between  57 and 64.  You  cannot  find out the exact
prefix length.

> options should be DNS encoding, shouldn't it? That seems more robust than 

Agreed.

> the 'typed scope list'. Couldn't the length of the list immediately precede 

I think,  it won't  make any  difference.  Let me  know, if there are any
serious issues on this.

---

From: Mark Stapp <[email-masked]>
Date: Mon, 21 Jan 2002 09:44:31 -0500

Vijay,

1) FQDN Option. I really think that we should use a single option that can 
convey both a complete FQDN or a partial 'hostname'. It's unnecessary to 
try to specify two options and the relationship between them. Certainly, 
there's no need to include the RCODE fields that were part of the v4 FQDN 
option: like the two name encodings in the v4 version, those fields were 
left in place because there was a large base of deployed clients who 
expected those fields to be present. I'd suggest that we specify the same 
method that's used in the v4 option to distinguish between fully-qualified 
and unqualified names: if the last label in the name field is null-length, 
the name is fully-qualified. If a client believes it knows a complete FQDN, 
it sends that name and terminates it accordingly. If it only knows a 
partial name, it sends the labels it knows.

>fields are not necessary.

As I said, I think that DNS updates will be performed by different parties 
in different environments, just as they are in IP4 networks. The option 
must contain enough information to permit a network's administrators to 
influence the choice of updater for zones that are under their control.

Like Bernie, I don't know what you mean here when you claim that no 
additional data is necessary. Your claim that temporary addresses' updates 
will be done by servers is a little confusing to me. Why do you assume 
that? You imply that non-temporary updates are clearly understood to be the 
responsibility of one party. I disagree: I think that the years of field 
experience we have demonstrates that there are a variety of valid dns 
update models.

>network with two prefixes and the client wants a particular one.

I think that the specification must be clear about the behavior that the 
paragraph in your reply describes. The server MAY consider the subnet 
specified as it considers the other information available to it about its 
allocation policies and about the client.

>I think,  it won't  make any  difference.  Let me  know, if there are any

There are so many examples of the field len/field value convention that I 
think it's much clearer to continue using that convention unless there's a 
very good reason not to. I don't think that there is such a reason in this 
case, and I think that it will make the specification and implementation of 
this option more robust if we retain that convention.

-- Mark

---

From: Vijay Bhaskar A K <[email-masked]>
Date: Wed, 23 Jan 2002 22:06:16 +0530 (IST)

> partial name, it sends the labels it knows.

Agreed.  But, i feel that,  insteading  of discussing  now on the fields
needed for FQDN  option, we can finalise  the DDNS updates and then come
back to format definition for FQDN option.

> allocation policies and about the client.

I will include whatever i have explained in the text for this option.

> this option more robust if we retain that convention.

I assumed  SLP DA address  and scope list as data, i didn't  want put an
len field in between.

-- 
____Vijay_Bhaskar_A_K____
______Inet_Services______
________HP_ISO___________
______Ph:_2051424________
____Telnet:_847_1424_____
___Pager:_9624_371137____

---

From: Richard Barr Hibbs <[email-masked]>
Date: Wed, 23 Jan 2002 21:59:30 -0800

> -----Original Message-----
> From: Vijay Bhaskar A K
> Sent: Friday, January 18, 2002 12:52
>
> - FQDN Option
>
...I want to reserve comments on this option until I've thought about it a
little bit more... comments by Mark, Bernie, and others have provoked my
curiosity to review this more thoroughly

> the  destination  address, and the second  address is the router for the
...I don't disagree with the anything but the unfortunate duplication of
field names: "destination prefix address" is used for both destination
address and router address.  I suggest that the prefix used for router
address should be renamed as "router prefix address."

> along with zero or more scopes supported by the DAs.
...here, the illustration is unclear:  it seems to suggest that there are
precisely two DA's and that the Typed Scope List is mandatory (and of
non-zero length).

> specified by the Service Location Protocol (SLP).
...here, again, the illustration is unclear, confusion arising because the
two Typed Scope Lists shown having identical names.

I also appreciate the effort that Vijay put into this proposal.

--Barr

---

From: Erik Guttman <[email-masked]>
Date: Mon, 28 Jan 2002 18:54:15 +0100 (MET)

Richard, Vijay,

I can briefly clarify the SLP DHC options.  These are being
revised from RFC 2610 in draft-guttman-svrloc-rfc2610bis-01.txt
I will add text to specify DHCPv6 options in the next revision.

> precisely two DA's and that the Typed Scope List is mandatory (and of

Please note that it is possible for the DA option to be sent 
without sending the SLP scope option.  When an SLP agent is 
configured with the DA option, it will request a SLPv2 DAAdvert 
from the DA whose address is listed, in order to obtain information 
about the DA, including which scopes the DA is configured with.
This is described in detail in draft-guttman-svrloc-rfc2608bis-02.txt

---

The analogy to v4 option 78, SLP Directory Agent Option, will be 

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |         OPTION_SLPDA          |             option-len        |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                                                               |
   |                          DA Address #1                        |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
                                . . . .
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |                                                               |
   |                                                               |
   |                          DA Address #N                        |
   |                                                               |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

One or more DA addresses are supplied.  The minimum length of the 
option will be 36 bytes.  The interpretation of this is field is
exactly the same as for option 78, except that it is used to 
configure a SLP v2 agent with the IPv6 address of a SLPv2 DA.
   
> two Typed Scope Lists shown having identical names.

Only one SLP Service Scope Option is sent to configure an SLP
agent.

---

The analogy to v4 option 79, SLP Service Scope Option, will be 

    0                   1                   2                   3
    0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   |        OPTION_SLPSCOPES       |          option-len           |
   +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
   | <Scope List> ...
   +--------------------

This option includes zero or more bytes of UTF-8 string.  Its 
minimum length is 4 bytes.  The interpretation of this field
is exactly as per DHCP option 79.

I have no doubt that these options will eventually assigned 
DHCPv6 option IDs as the rfc2610bis document proceeds.

Erik