DHC J. Brzozowski
Internet-Draft Comcast Cable
Expires: December 18, 2006 K. Kinnear
B. Volz
S. Zeng
Cisco Systems, Inc.
June 16, 2006
DHCPv6 Leasequery
<draft-brzozowski-dhc-dhcvp6-leasequery-00.txt>
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Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This document specifies leasequery for the Dynamic Host Configuration
Protocol for IPv6 (DHCPv6) which can be used as a means to obtain
lease information about DHCPv6 clients from a DHCPv6 server. This
document specifies the scope of data that can be retrieved as well as
both DHCPv6 leasequery requestor and server behavior.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3
3. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 4
3.1. On-demand Leasequery . . . . . . . . . . . . . . . . . . . 4
3.2. Anticipatory Leasequery . . . . . . . . . . . . . . . . . 4
3.3. Query Types . . . . . . . . . . . . . . . . . . . . . . . 5
4. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 6
4.1. Message and Option Definitions . . . . . . . . . . . . . . 6
4.1.1. Messages . . . . . . . . . . . . . . . . . . . . . . . 6
4.1.2. Options . . . . . . . . . . . . . . . . . . . . . . . 7
4.1.3. Status Codes . . . . . . . . . . . . . . . . . . . . . 12
4.1.4. Transmission and Retransmission Parameters . . . . . . 13
4.2. Message Validation . . . . . . . . . . . . . . . . . . . . 13
4.2.1. LEASEQUERY . . . . . . . . . . . . . . . . . . . . . . 13
4.2.2. LEASEQUERY-REPLY . . . . . . . . . . . . . . . . . . . 13
4.3. DHCPv6 Leasequery Requestor Behavior . . . . . . . . . . . 13
4.3.1. Creation of LEASEQUERY . . . . . . . . . . . . . . . . 14
4.3.2. Transmission of LEASEQUERY . . . . . . . . . . . . . . 14
4.3.3. Receipt of LEASEQUERY-REPLY . . . . . . . . . . . . . 15
4.3.4. Handling DHCPv6 Client Data from Multiple Sources . . 16
4.4. DHCPv6 Leasequery Server Behavior . . . . . . . . . . . . 17
4.4.1. Receipt of LEASEQUERY Messages . . . . . . . . . . . . 17
4.4.2. Processing a LEASEQUERY . . . . . . . . . . . . . . . 18
4.4.3. Constructing a Client's OPTION_CLIENT_DATA . . . . . . 19
4.4.4. Transmission of LEASEQUERY-REPLY Messages . . . . . . 19
4.5. Processing of Bulk Queries . . . . . . . . . . . . . . . . 19
4.5.1. Conceptual Model . . . . . . . . . . . . . . . . . . . 20
4.5.2. Requestor Processing . . . . . . . . . . . . . . . . . 21
4.5.3. Server Processing . . . . . . . . . . . . . . . . . . 23
5. Security Considerations . . . . . . . . . . . . . . . . . . . 24
6. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 25
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 26
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 26
8.1. Normative References . . . . . . . . . . . . . . . . . . . 26
8.2. Informative References . . . . . . . . . . . . . . . . . . 27
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 28
Intellectual Property and Copyright Statements . . . . . . . . . . 29
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1. Introduction
The DHCPv6 [2] protocol specifies a mechanism for the assignment of
both IPv6 address and configuration information to IPv6 nodes. IPv6
Prefix Options for DHCPv6 [4] specifies a mechanism for the automated
delegation of IPv6 prefixes and related options. Similar to DHCPv4
[5], DHCPv6 servers maintain authoritative information related to its
operations including but not limited to lease information for IPv6
addresses and delegated prefixes.
The requirement exists in various types of IPv6 deployments,
particularly those of a broadband variety, to leverage DHCPv6 [2] for
retrieving data related to the operation of DHCPv6 servers
programmatically. In particular it is desirable to be able to
extract lease information about IPv6 addresses and delegated prefixes
assigned using DHCPv6 [2, 4]. Specific examples where this
information has illustrated value are in broadband networks to
facilitate access control by edge devices. This capability to
programitcally extract lease data from the DHCPv6 server is called
leasequery.
Existing specifications, such as [3] are leveraged as a basis for the
definition of the DHCPv6 leasequery protocol. The motivations and
justifications identified in [3] also generally apply to this
specification. Furthermore, advancements in DHCPv6 [2] are expanded
upon to specify additional means by which IPv6 address and delegated
prefix lease data can be retrieved through DHCPv6 leasequery.
2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [1].
DHCPv6 terminology is defined in [2]. Terminology specific to DHCPv6
leasequery can be found below:
client(s) The nodes that have one or more bindings
with a DHCPv6 server. This does not refer to
the node issuing the LEASEQUERY unless it
itself has one or more bindings with a DHCPv6
server.
requestor The node that sends LEASEQUERY messages to one
or more servers to retrieve information on the
bindings for a client or clients.
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3. Protocol Overview
The focus of this document is to define a protocol that allows
processes and devices that wish to access information from a DHCPv6
server to do so in a lightweight and convenient manner. It is
especially appropriate for processes and devices that already
interpret DHCPv6 messages.
One important motivating example is that the LEASEQUERY message
allows access concentrators to query DHCP servers to obtain location
information of broadband access network devices.
The LEASEQUERY message is a query message only and does not affect
the state of the IPv6 address or prefix, or the binding information
associated with it.
The leasequery capability described in this document parallels the
DHCPv4 leasequery capability documented in [3]. As such, it shares
many of the basic motivations, design goals and constraints as the
capability described in Section 4 of [3]. While the DHCPv4
leasequery capability was structured to return only a relatively
small amount of information on each request, some aspects of the
DHCPv6 leasequery capability may require the return of considerably
more data than will fit in a single DHCPv6 reply. The following
sections describe these situations.
3.1. On-demand Leasequery
One approach for requesting information from a DHCPv6 server using
the leasequery capability is to request just the information
necessary to satisfy an immediate need. If the requestor is an
access concentrator, then the immediate need will typically be that
it has received an IPv6 packet and it needs to refresh its
information concerning the DHCPv6 client to which that an IPv6
address is currently leased. In this case, the request will
typically be by Address, DUID, or by Device ID. See Section 3.3 for
details. The information returned will typically be for a single
client. The information will fit in the return message, and so no
special handling is required. This approach fits clearly into the
single request/response cycle common to other DHCPv6 message
exchanges.
3.2. Anticipatory Leasequery
A second approach for requesting information from a DHCPv6 server is
to use the leasequery capability to rebuild an internal data store
containing information available from a DHCPv6 server. The
rebuilding of the data store in this approach takes place as soon as
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possible after the need to rebuild it is discovered (such as on
booting), and doesn't wait on the receipt of specific packets to
trigger a piecemeal database update (as is the case for on-demand
leasequery). In this approach, the requestor will send LEASEQUERY
messages in advance of actually receiving any packets to which the
leasequery information should relate.
The requests that a requestor would use to employ this approach would
typically be those by Prefix or Link.
The challenge presented by this approach is that the quantity of
information returned to the requestor is usually many times more than
could fit into a single LEASEQUERY-REPLY message. Thus, to support
the anticipatory leasequery approach we need to develop a way to
return multiple reply messages that all relate to a single query.
When the reply to a LEASEQUERY message will not fit entirely within
one LEASEQUERY-REPLY message, then an OPTION_LQ_COOKIE option is
returned in the LEASEQUERY-REPLY message. The appearance of the
OPTION_LQ_COOKIE option in a LEASEQUERY-REPLY message indicates to
the requestor that additional data beyond that in the current
LEASEQUERY-REPLY message is available for the query. The requestor
then submits the LEASEQUERY message, with the same OPTION_LQ_QUERY
option but with the addition of the OPTION_LQ_COOKIE option, to the
DHCPv6 server. When the DHCPv6 server receives the LEASEQUERY
message, the information in the OPTION_LQ_COOKIE option allows the
DHCPv6 server to return additional information concerning the results
of the query.
If you visualize the information that a DHCPv6 server would return
from a single leasequery as a sequence of OPTION_CLIENT_DATA options,
then the contents of the OPTION_LQ_COOKIE option are essentially a
key into that sequence, and allow the server to return the next items
in the sequence along with a different OPTION_LQ_COOKIE option with a
new key into the sequence of OPTION_CLIENT_DATA options still to be
returned.
See Section 4.5 for specific details of this approach.
3.3. Query Types
Leasquery provides for the following queries:
Query by DUID - This query allows a device to request from a server
the bindings for a specific client on a specific link or any
instances of the client on any of the server's configured links.
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Query by IPv6 address - This query allows a device to request from a
server the bindings for a client that either is bound to the
address or has been delegated the prefix that contains the
address. This is likely the on-demand request that an access
concentrator that receives an IPv6 packet would make.
Query by IPv6 prefix - This query allows a device to request from a
server the bindings for clients that have been assigned addresses
or delegated prefixes within the requested prefix, or were
delegated the prefix.
Query by Link - This query allows a device to request from a server
the bindings for clients on a particular link or on all links
configured in a server. This is likely the anticipatory request
that an access concentrator would make when it discovers a need to
rebuild its data store.
Query by Remote ID - This query allows a device to request from a
server the clients and their bindings that match a remote-id.
Query by Device ID - This query allows a device to request from a
server the clients and their bindings that match a device-id.
It is important to note that all queries determine the clients to be
returned and that all bindings for a client (on a link) are returned.
Thus, a Query by IPv6 address may return one client and will return
all of the bindings that client has on the link for the address. It
is up to the receiver of the information as to what information it
wants to use.
4. Protocol Details
4.1. Message and Option Definitions
4.1.1. Messages
The LEASEQUERY and LEASEQUERY-REPLY messages use the Client/Server
message formats described in [2], section 6. Two new message codes
are defined:
LEASEQUERY (TBD) - A requestor sends a LEASEQUERY message to any
available server to obtain information on a client's or clients'
leases. The options in an OPTION_LQ_QUERY determine the query.
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LEASEQUERY-REPLY (TBD) - A server sends a LEASEQUERY-REPLY message
containing client data in response to a LEASEQUERY message.
4.1.2. Options
4.1.2.1. Query Option
The Leasequery Query option is used only in a LEASEQUERY message and
identifies the query being performed. The option includes the query
type, link-address (or 0::0 for all links), and option(s) to provide
data needed for the query.
The format of the Query option is shown below:
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_LQ_QUERY | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| query-type | |
+-+-+-+-+-+-+-+-+ |
| |
| link-address |
| |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| | .
+-+-+-+-+-+-+-+-+ .
. query-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_LQ_QUERY (TBD)
option-len 17 + length of query-options field.
link-address A global address that will be used by the
server to identify the link to which the
query applies, or 0::0 if the server is to
search all its links.
query-type the query requested (see below).
query-options the options related to the query.
The query-type and required query-options for the query types
(Section 3.3) are:
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QUERY_BY_CLIENTID (1) - The query-options MUST contain an
OPTION_CLIENTID option [2]. The link-address field MUST specify
an address for the link on which the client is located or 0::0 for
all links for which the server is configured. Only the requested
client's information is returned (if available) in the
OPTION_CLIENT_DATA option. If the link-address is 0::0, multiple
OPTION_CLIENT_DATA options may be returned, one for each link on
which the client has one or more bindings.
QUERY_BY_ADDRESS (2) - The query-options MUST contain an
OPTION_IAADDR option [2]. The link-address field MUST specify an
address for the link on which the address is located if the
address in the OPTION_IAADDR option is of insufficient scope or
0::0. Only the information for a client that has a lease for the
specified address or was delegated a prefix that contains the
specified address is returned (if available).
QUERY_BY_PREFIX (3) - The query-options MUST contain an
OPTION_IAPREFIX option [4]. The link-address field MUST specify
an address for the link on which the prefix is located if the
prefix in the OPTION_IAPREFIX option is of insufficient scope or
0::0. Only the information for clients with bindings on the
prefix or were delegated the specified prefix are returned (if
available).
QUERY_BY_LINK (4) - There are no required query-options options for
this query. The link-address field MUST specify an address for
the link on which the clients are located or 0::0 for all links
for which the server is configured. Only information for the
clients that were assigned addresses or delegated prefixes on the
specified link is returned (if available).
QUERY_BY_REMOTE_ID (5) - The query-options MUST contain an
OPTION_REMOTE_ID option [7]. The link-address field MUST specify
an address for the link on which the client is located or 0::0 for
all links for which the server is configured. Only the clients on
the link or on all links that have the specified remote-id are
returned.
QUERY_BY_DEVICE_ID (6) - The query-options MUST contain an
OPTION_DEVICE_ID [8]. The link-address field MUST specify an
address for the link on which the client is located or 0::0 for
all links for which the server is configured. Only the clients on
the link or on all links that have the specified device-id are
returned.
The query-options MAY also include an OPTION_ORO option [2] to
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indicate the options for each client that the requestor would like
the server to return. Note that this OPTION_ORO is distinct and
separate from an OPTION_ORO that may be in the requestor's LEASEQUERY
message.
If a server receives an OPTION_LQ_QUERY with a query-type it does not
support, the server SHOULD return an UnknownQueryType status-code.
If a server receives a supported query-type but the query-options is
missing a required option, the server SHOULD return a MalformedQuery
status-code.
4.1.2.2. Reply Size Option
The Reply Size option is sent to a server in a LEASEQUERY message to
indicate the largest LEASEQUERY-REPLY message that the requestor is
prepared to receive. A server uses the option to determine how much
data it can return to the requestor in a single reply.
The format of the Reply Size option is shown below:
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_REPLY_SIZE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| reply-size |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_REPLY_SIZE (TBD)
option-len 2
reply-size The maximum number of octets the requestor
is prepared to receive from the server. This
limits the size of the LEASEQUERY-REPLY
message.
If a requestor does not supply this option, the server MUST use 1024
octets. The requestor must be aware of the recommendations on packet
sizes and the use of fragmentation in section 5 of [6].
Given a reply size, if a LEASEQUERY-REPLY message can not contain at
least one OPTION_CLIENT_DATA (and OPTION_LQ_COOKIE if more than one
client's data is to be returned) the server must return the
LEASEQUERY-REPLY with an OPTION_STATUS_CODE option [2] with the
TooShort status-code.
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4.1.2.3. Cookie Option
The Leasequery Cookie option is returned by a server when the reply
can not fit into a single LEASEQUERY-REPLY message. The requestor
may then send the same request, including the server's Cookie Option,
to obtain the next portion of the reply. A server's reply is
complete when no Cookie option is included.
If a requestor sends a request with this option, it MUST also include
the OPTION_SERVERID option [2] that was returned in the LEASEQUERY-
REPLY. A server MUST discard any request that includes this option
without an OPTION_SERVERID option.
The format of the LEASEQUERY Cookie option is shown below:
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_LQ_COOKIE | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. cookie-data .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_LQ_COOKIE (TBD)
option-len length, in octets, of the cookie-data field.
The minimum length is 1 octet.
cookie-data The opaque cookie data.
The cookie-data field's contents and length are completely up to the
server and MUST be treated as opaque data by the requestor. The
requestor MUST send the same option back to the server to retrieve
the next portion of a reply. The cookie-data serves to identify to
the server the next client to return.
If the server receives this option with cookie-data that it can not
validate, the server MUST return a LEASEQUERY-REPLY with an
OPTION_STATUS_CODE option [2] with the StaleCookie status-code.
4.1.2.4. Client Data Option
The Client Data option is used to encapsulate the data for a single
client on a single link in a LEASEQUERY-REPLY message. If a query is
done for multiple links, multiple Client Data options for the same
client may be returned and the addresses and/or delegated prefixes in
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the binding for the client should be sufficient for the requestor to
determine the link.
The format of the Client Data option is shown below:
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_CLIENT_DATA | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
. client-options .
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_CLIENT_DATA (TBD)
option-len length, in octets, of the encapsulated client-
options field.
client-options the options associated with this client.
The encapsulated client-options include the OPTION_CLIENTID,
OPTION_IAADDR, OPTION_IAPREFIX, and OPTION_CLT_TIME options and other
options specific to the client and requested by the requestor in the
OPTION_ORO in the OPTION_LQ_QUERY's query-options. The server MUST
return all of the clients' statefully assigned addresses and
delegated prefixes, with a non-zero valid lifetime, on the link.
4.1.2.5. Client Last Transaction Time Option
The Client Last Transaction Time option is encapsulated in an
OPTION_CLIENT_DATA and identifies how long ago the server last
communicated with the client, in seconds.
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The format of the Client Last Transaction Time option is shown below:
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_CLT_TIME | option-len |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| client-last-transaction-time |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
option-code OPTION_CLT_TIME (TBD)
option-len 4
client-last-transaction-time
the number of seconds since the server last
communicated with the client (on that link).
The client-last-transaction-time is a positive value and reflects the
number of seconds since the server last communicated with the client
(on that link).
4.1.3. Status Codes
The following new status codes are defined:
UnknownQueryType (TBD) - The query-type is unknown to or not
supported by the server.
MalformedQuery (TBD) - The query is not valid, for example a required
query-option is missing from the OPTION_LQ_QUERY.
StaleCookie (TBD) - The cookie supplied by the requestor in a
LEASEQUERY message is not (or no longer) valid. The requestor
SHOULD repeat the LEASEQUERY from the beginning (i.e., without a
cookie). However, it SHOULD only retry a query a limited number
of times.
TooShort (TBD) - The Reply Message Size option (or the default size)
is too short to contain at least a single OPTION_CLIENT_DATA. The
requestor should retry the query with a larger reply-size value.
A simple policy is to use a small size until a larger is needed,
and then use the largest desired to complete that query.
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NotConfigured (TBD) - The server does not have the target address,
prefix, or link in its configuration.
NotAllowed (TBD) - The server does not allow the requestor to issue
this LEASEQUERY.
4.1.4. Transmission and Retransmission Parameters
This section presents a table of values used to describe the message
transmission behavior for leasequery.
Parameter Default Description
----------------------------------
LQ_TIMEOUT 1 sec Initial LEASEQUERY timeout
LQ_MAX_RT 10 secs Max LEASEQUERY timeout value
LQ_MAX_RC 5 Max LEASEQUERY retry attempts
4.2. Message Validation
4.2.1. LEASEQUERY
Requestors and clients MUST discard any received LEASEQUERY messages.
Servers MUST discard any received LEASEQUERY messages that meet any
of the following conditions:
o the message does not include an OPTION_CLIENTID option.
o the message includes an OPTION_SERVERID option but the contents of
the OPTION_SERVERID option does not match the server's identifier.
o the message does not include an OPTION_LQ_QUERY option.
4.2.2. LEASEQUERY-REPLY
Requestors MUST discard any received LEASEQUERY-REPLY messages that
meet any of the following conditions:
o the message does not include an OPTION_SERVERID option.
o the message does not include an OPTION_CLIENTID option or the
contents of the OPTION_CLIENTID option do not match the DUID of
the requestor.
o the "transaction-id" field in the message does not match the value
used in the original message.
Servers and Relay Agents (on the server port, 547 [2]) MUST discard
any received LEASEQUERY-REPLY messages.
4.3. DHCPv6 Leasequery Requestor Behavior
This section describes how a requestor initiates lease data retrieval
from DHCPv6 servers. If the server generates more data than can fit
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into one reply message, then the requestor continues lease data
retrieval as described in Section 4.5.
4.3.1. Creation of LEASEQUERY
The requestor sets the "msg-type" field to LEASEQUERY. The requestor
generates a transaction ID and inserts this value in the
"transaction-id" field.
The requestor MUST include an OPTION_CLIENTID option to identify
itself to the server.
The requestor MUST include an OPTION_LQ_QUERY option and set the
query-type, link-address, and query-options as appropriate to the
query-type (Section 4.1.2.1).
The requestor SHOULD include an OPTION_SERVERID if it is not
unicasting the LEASEQUERY yet only wants a response from a specific
server.
The requestor SHOULD include an OPTION_REPLY_SIZE to specify the
largest LEASEQUERY-REPLY it is willing to accept.
4.3.2. Transmission of LEASEQUERY
The requestor MAY be configured to use a list of destination
addresses, which MAY include unicast addresses, the All_DHCP_Servers
multicast address, or other addresses selected by the network
administrator. If the requestor has not been explicitly configured,
it MAY use the All_DHCP_Servers multicast address as the default.
The requestor SHOULD send LEASEQUERY to one or more DHCPv6 servers
which are known to possess authoritative information concerning the
query target.
In the absence of information concerning which DHCPv6 servers might
possess authoritative information on the query target, the requestor
SHOULD send LEASEQUERY to all DHCPv6 servers that the requestor knows
about or is configured with. For example, the requestor MAY send
LEASEQUERY to the All_DHCP_Servers multicast address.
The requestor transmits LEASEQUERY messages according to section 14
of [2], using the following parameters:
IRT LQ_TIMEOUT
MRT LQ_MAX_RT
MRC LQ_MAX_RC
MRD 0
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If the message exchange fails, the requestor takes an action based on
the requestor's local policy. Examples of actions the requestor
might take include:
o Select another server from a list of servers known to the
requestor.
o Send to multiple servers by multicasting to the All_DHCP_Servers
address.
o Terminate the leasequery.
4.3.3. Receipt of LEASEQUERY-REPLY
If a LEASEQUERY-REPLY contains an OPTION_LQ_COOKIE, the requestor
SHOULD continue the bulked leasequery as described in Section 4.5.
This section specifies the behavior of the requestor regarding the
processing of a single (or initial) LEASEQUERY-REPLY message.
A successful LEASEQUERY-REPLY is one without an OPTION_STATUS_CODE
with an error code and may or may not contain client data in
OPTION_CLIENT_DATA options. A successful LEASEQUERY MAY contain no
OPTION_CLIENT_DATA if no clients matched the query.
An unsuccessful LEASEQUERY-REPLY is one that has an
OPTION_STATUS_CODE with an error code.
4.3.3.1. Receiving Successful LEASEQUERY-REPLY
Upon the receipt of a successful LEASEQUERY-REPLY in response to a
LEASEQUERY, the requestor MUST extract the client data in the
LEASEQUERY-REPLY and may update its binding information database.
The LEASEQUERY-REPLY SHOULD contain an OPTION_SERVER_RSN option [9]
and the requestor SHOULD only update its binding information database
as described in [9].
If an OPTION_CLIENT_DATA contains no OPTION_CLT_TIME, then the
requestor SHOULD silently discard the OPTION_CLIENT_DATA option. The
existence of such an OPTION_CLIENT_DATA SHOULD NOT affect the
processing of other OPTION_CLIENT_OPTIONs by the requestor.
The requestor MUST be prepared to handle an OPTION_CLIENT_DATA that
contains more or fewer options than listed in the OPTION_ORO of the
LEASEQUERY message, and to handle multiple OPTION_CLIENT_DATA
options, as many queries may return data on more than a single
client.
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4.3.3.2. Receiving Unsuccessful LEASEQUERY-REPLY
An unsuccessful LEASEQUERY-REPLY contains an OPTION_STATUS_CODE with
one of the status codes listed in Section 4.1.3 or in [2] except
Success.
Depending on the status code, the requestor may retry the query (such
as for TooShort, but with a larger reply-size in the
OPTION_REPLY_SIZE option, and for StaleCookie, but without the
OPTION_LQ_COOKIE option), try a different server (such as for
NotAllowed, NotConfigured, and UnknownQueryType), or try a different
or corrected query (such as for UnknownQueryType and MalformedQuery).
4.3.4. Handling DHCPv6 Client Data from Multiple Sources
A requestor may receive lease data on the same client from the same
DHCPv6 server in response to different types of LEASEQUERY. If a
LEASEQUERY is sent to multiple servers, the requestor may receive
from several servers lease data on the same DHCPv6 client.
Additionally, if a requestor is an access concentrator, it may
receive lease data from other than leasequery exchanges, e.g., [9].
This section describes how the requestor handles multiple lease data
sources on the same DHCPv6 client from the same server or different
servers.
The client data from the different sources may be disjoint or
overlapping. The disjoint and overlapping relationship can happen
between data from the same server or different servers.
If client data from two sources on the same client are of different
types or values, then the data are disjoint. An example of data of
different types is when a requestor receives an IPv6 address lease
from one server and a prefix lease from another server, both assigned
to the same client. An example of different values (but the same
type) is when a requestor receives two IPv6 address leases from two
different servers, both assigned to the same client, but the leases
are on two different IPv6 addresses. If the requestor receives
disjoint client data from different sources, it SHOULD merge them.
If client data from two sources on the same client are of the same
type and value, then the data are overlapping. An example of
overlapping data is when a requestor receives a lease on the same
IPv6 address from two different servers. Overlapping client data are
also called conflicting data.
The requestor SHOULD use the OPTION_SERVER_RSN [9] to resolve data
conflicts originated from the same server, and SHOULD accept data
with the higher server-sequence-number. The requestor SHOULD use the
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OPTION_CLT_TIME to resolve data conflicts originated from different
servers, and SHOULD accept data with most recent OPTION_CLT_TIME.
4.4. DHCPv6 Leasequery Server Behavior
A DHCPv6 server sends LEASEQUERY-REPLY messages in response to valid
LEASEQUERY messages it receives to return the statefully assigned
addresses, delegated prefixes, and other information about clients
that match the query.
4.4.1. Receipt of LEASEQUERY Messages
Upon receipt of a valid LEASEQUERY message, the DHCPv6 server locates
the requested clients, collects data on the clients, and constructs
and returns a LEASEQUERY-REPLY. A LEASEQUERY message can not be used
to assign, release, or otherwise modify bindings or other
configuration information.
The server constructs a LEASEQUERY-REPLY message by setting the "msg-
type" field to LEASEQUERY-REPLY, and copying the transaction ID from
the LEASEQUERY message into the transaction-id field.
If the query-type in the OPTION_LQ_QUERY option is not a known or
supported value, the server adds an OPTION_STATUS_CODE option with
the UnknownQueryType status code and sends the LEASEQUERY-REPLY to
the requestor. If the query-options do not contain the required
options for the query-type, the server adds an OPTION_STATUS_CODE
option with the MalformedQuery status code and sends the LEASEQUERY-
REPLY to the client.
A server may also restrict LEASEQUERY messages, or query-types, to
certain requestors. In this case, the server MAY discard the
LEASEQUERY message or MAY add an OPTION_STATUS_CODE option with the
NotAllowed status code and send the LEASEQUERY-REPLY to the
requestor.
If the OPTION_LQ_COOKIE option is present in the LEASEQUERY message,
the server is engaged in a bulked query with the requestor. The
server behaviors upon the receipt of such a LEASEQUERY is described
in Section 4.5.
If the OPTION_LQ_QUERY specified a non-zero link-address, the server
MUST use the link-address to find the appropriate link for the
client. Otherwise, the server uses the address from the
OPTION_IAADDR option (if the query-type is QUERY_BY_ADDRESS) or the
prefix from the OPTION_IAPREFIX option (if the query-type is
QUERY_BY_PREFIX), to find the appropriate link for the client. There
are three possible outcomes from this processing:
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1. No address or prefix is specified, in which case the server MUST
perform the query on all of its configured links.
2. The server locates the specified link, in which case the server
MUST only perform the query on that link.
3. No link is found, in which case the server adds an
OPTION_STATUS_CODE option with the NotConfigured status code and
sends the LEASEQUERY-REPLY to the client.
At this point, the server uses the data in the OPTION_LQ_QUERY and
OPTION_LQ_COOKIE (if present) to initiate or resume the query. The
result of the query will be zero or more clients. This will result
in zero or more OPTION_CLIENT_DATA option being added to the
LEASEQUERY-REPLY and possibly a OPTION_LQ_COOKIE option as discussed
in Section 4.4.3 and Section 4.5.
4.4.2. Processing a LEASEQUERY
The following sections assume a single link is being searched for the
targets of a query. If multiple links are being searched, the order
is up to the server and it essentially performs the actions below on
each link. How and in what order a server performs the query is
completely up to it; however, note the requirements in Section 4.5 to
assure that a query eventually terminates. Requestors MUST NOT
assume any specific behavior or order of the returned data.
4.4.2.1. QUERY_BY_DUID
This query requires that the server return the client identified by
the OPTION_CLIENTID in the LEASEQUERY, if that client has a binding.
4.4.2.2. QUERY_BY_ADDRESS
This query requires that the server return the client that is bound
to the address or that has been delegated the prefix that contains
the address.
4.4.2.3. QUERY_BY_PREFIX
This query requires that the server return the clients that have
bindings for addresses or delegated prefixes that are contained in
the specified prefix. The server MUST only search its explicitly
configured prefixes; this query type is not provided to allow a
requestor to specify an arbitrary range of addresses about which to
return bindings.
4.4.2.4. QUERY_BY_LINK
This query requires that the server return the clients that have
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bindings for addresses or delegated prefixes on the specified link.
4.4.2.5. QUERY_BY_REMOTE_ID
This query requires that the server return the clients that match the
specified OPTION_REMOTE_ID [7].
4.4.2.6. QUERY_BY_DEVICE_ID
This query requires that the server return the clients whose
associated Device-IDs match the specified OPTION_DEVICE_ID in the
LEASEQUERY [8].
4.4.3. Constructing a Client's OPTION_CLIENT_DATA
An OPTION_CLIENT_DATA option in a LEASEQUERY-REPLY message MUST
minimally contain the following data.
1. OPTION_CLIENTID
2. OPTION_IAADDR
3. OPTION_IAPREFIX
4. OPTION_CLT_TIME
Depending on the bindings the client has on a link, either
OPTION_IAADDR options, IAPREFIX options, or both may be present.
The OPTION_CLIENT_DATA SHOULD include options requested in the
OPTION_ORO of the OPTION_LQ_QUERY option in the LEASEQUERY message
and that are acceptable to return based on the list of "sensitive
options", discussed below.
DHCPv6 servers SHOULD be configurable with a list of "sensitive
options" that must not be returned to the requestor when specified in
the OPTION_ORO of the OPTION_LQ_QUERY option in the LEASEQUERY
message. Any option on this list MUST NOT be returned to a
requestor, even if requested by that requestor.
4.4.4. Transmission of LEASEQUERY-REPLY Messages
The server sends the LEASEQUERY-REPLY message as described in the
"Transmission of Reply Messages" section of [2].
4.5. Processing of Bulk Queries
Any time there is more data than will fit into a particular
LEASEQUERY-REPLY message, then the DHCPv6 server MUST return a
LEASEQUERY-REPLY message with an OPTION_LQ_COOKIE option indicating
that there is more data available for this query.
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All requestors MUST support bulked queries unless they restrict their
queries to those that will only return a single client's data. For
example, a Query By DUID with a specific link-address can ever only
return a single client. A Query By Address should only return a
single client; however that only holds if the DHCPv6 server is not
performing stateful address assignment or prefix delegation for a
delegated prefix.
Whenever a DHCPv6 server is preparing information for transmission to
the requestor, it MUST ensure that all of the information in a
particular OPTION_CLIENT_DATA option will fit in the LEASEQUERY-REPLY
message. That is to say that the information in a single
OPTION_CLIENT_DATA option MUST NOT be split over two LEASEQUERY-REPLY
messages.
In the event that an OPTION_CLIENT_DATA will not fit entirely within
a LEASEQUERY-REPLY message, the OPTION_CLIENT_DATA MUST NOT be placed
in that message but instead an OPTION_LQ_COOKIE option MUST BE placed
in the LEASEQUERY-REPLY message indicating that additional
information is available from the DHCPv6 server regarding the current
LEASEQUERY query. If there is not enough space, then the last
OPTION_CLIENT_DATA option (or options) MUST be removed from the
LEASEQUERY-REPLY message in order to make enough room for the
OPTION_LQ_COOKIE option.
The information in the OPTION_LQ_COOKIE option is opaque to everyone
but the DHCPv6 server who created the OPTION_LQ_COOKIE option. It is
only used to tell the DHCPv6 server to continue returning additional
data for this query and to give the DHCPv6 server some information as
to which information remains to be returned. There is no requirement
placed on the DHCPv6 server for any particular structure in the
OPTION_LQ_COOKIE option.
The conceptual basis of the OPTION_LQ_COOKIE option is that this
option is a key which moves through the database and represents the
position before which data has been returned and after which data has
not been returned. It represents a "scan" through the database for
all information to return to a particular LEASEQUERY.
4.5.1. Conceptual Model
The conceptual model for the OPTION_LQ_COOKIE option and bulk queries
in general is as follows. Please note that this is a conceptual
model only, and does not presuppose a particular implementation
approach. Again, this is only a way to think about the
OPTION_LQ_COOKIE option, not a recommendation on how to implement it.
Imagine the OPTION_CLIENT_DATA options that the DHCPv6 server would
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like to return for a particular LEASEQUERY message. These
OPTION_CLIENT_DATA options are ordered in a particular sequence -- a
sequence likely known only to the DHCPv6 server. The
OPTION_LQ_COOKIE option is essentially a key into this sequence of
OPTION_CLIENT_DATA options. Thus, when the DHCPv6 server has more
information in the sequence of OPTION_CLIENT_DATA options to return
than fits in one message, it returns an OPTION_LQ_COOKIE. The
OPTION_LQ_COOKIE is essentially a key to the next OPTION_CLIENT_DATA
option that it would return for this query if there were more space
in the LEASEQUERY-REPLY message.
When the requestor receives a LEASEQUERY-REPLY containing a
OPTION_LQ_COOKIE option, it knows that additional data is available
for the query in the original LEASEQUERY message. It processes the
data that is received in the LEASEQUERY-REPLY message and then, in
order to receive the next message-worth of data, it sends another
LEASEQUERY message which MUST contain exactly the same query
parameters as the previous message and which MUST contain the
OPTION_LQ_COOKIE option and the OPTION_SERVERID option from the last
LEASEQUERY-REPLY.
The DHCPv6 server then receives the new LEASEQUERY message and looks
for an OPTION_LQ_COOKIE option which it finds. From the key in the
OPTION_LQ_COOKIE option it determines where in the sequence of
OPTION_CLIENT_DATA options it stopped when filling up the previous
LEASEQUERY-REPLY message, and it fills up another LEASEQUERY-REPLY
message with the next OPTION_CLIENT_DATA options that fit, and
returns an OPTION_LQ_COOKIE option which points to the first
OPTION_CLIENT_DATA option that didn't fit into the LEASEQUERY-REPLY
message.
This is only a conceptual model, because the DHCPv6 server is not
required to keep a list of all of the OPTION_CLIENT_DATA options that
it would like to return in response to a particular LEASEQUERY
message - that would require a potentially large amount of state to
be held for every active sequence of LEASEQUERY query series. A
DHCPv6 server implementation may hold such state, but there is no
requirement that it do so. The issues that may arise from not
holding such state for active queries are discussed below.
4.5.2. Requestor Processing
Whenever a requestor sends a LEASEQUERY message to a DHCPv6 server
which contains an OPTION_LQ_COOKIE option, the data within that
option MUST be identical to bytes received in an OPTION_LQ_COOKIE
option in the last LEASEQUERY-REPLY from that same DHCPv6 server.
The requestor MUST be prepared to process a LEASEQUERY-REPLY message
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which contains an OPTION_LQ_COOKIE option, indicating additional data
is available. The requestor MUST also be prepared to receive an
error when sending any subsequent LEASEQUERY message containing an
OPTION_LQ_COOKIE option.
It is possible that some implementations of the LEASEQUERY message
will require state memory on the DHCPv6 server, and so a server may
encode some state identifier in the OPTION_LQ_COOKIE option. If that
state information is not available when the DHCPv6 server receives a
LEASEQUERY message with an OPTION_LQ_COOKIE option, then the DHCPv6
server MUST return a StaleCookie error status. This is only an
example of why a DHCPv6 server might return an error to a LEASEQUERY
message which contains an OPTION_LQ_COOKIE option -- it is not meant
to restrict the DHCPv6 server in any way. An error may be returned
on any LEASEQUERY message with an OPTION_LQ_COOKIE and the requestor
MUST be able to deal with it.
In the event that the requestor who sent a LEASEQUERY receives a
StaleCookie error on a LEASEQUERY-REPLY message from the DHCPv6
server, then the requestor SHOULD restart the LEASEQUERY exchange
message from the beginning. In particular, the requestor MUST NOT
include an OPTION_LQ_COOKIE option in the subsequent LEASEQUERY
message. It SHOULD NOT throw away all of the existing information
already received, but it MUST be prepared to receive different and
possibly more up to date information than it received previously.
The requestor needs to recognize that information that is returned in
multiple LEASEQUERY-REPLYs resulting from a single query MAY not be
from one instant in time, but rather MAY represent a series of
snapshots of different segments of the database.
The requestor SHOULD use the OPTION_SERVER_RSN and OPTION_CLT_TIME
options to distinguish more current from less current
OPTION_CLIENT_DATA information as discussed in Section 4.3.4.
In the event that the requestor is sending in a LEASEQUERY message in
order to perform an "Anticipatory Leasequery", as described in
Section 3.2, presumably there is some internal database it is
attempting to reestablish by using the LEASEQUERY messages. In the
usual case, this internal database is maintained by a mechanism other
than leasequery (e.g. [9]), and the LEASEQUERY messages are just used
to reestablish the current state of this internal database. In the
cases where this situation exists, the requestor SHOULD reestablish
the mechanism used to maintain this internal database prior to the
time that it sends the first anticipatory LEASEQUERY message.
If this is done, then there may well be some cases where the data
obtained from a LEASEQUERY exchange is different than the data
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determined from the database maintenance mechanism; how to handle
this is described in Section 4.3.4.
4.5.3. Server Processing
When the DHCPv6 server receives a LEASEQUERY message containing a
OPTION_LQ_COOKIE option and an OPTION_SERVERID option, it compares
the OPTION_SERVERID option with its DUID to determine if the
LEASEQUERY message is directed at itself. It then uses the
OPTION_LQ_COOKIE and OPTION_LQ_QUERY options to generate additional
OPTION_CLIENT_DATA options to return to the requestor. The DHCPv6
server MUST be able to generate output in such a way that it can use
information in the OPTION_LQ_COOKIE option to determine which
information it has already returned and which information has yet to
be returned as a result of the query embodied in the LEASEQUERY
message.
One issue is that the underlying data may well have changed in the
time since the first query was received and processed, yielding
several possible inconsistencies in the data returned to the
requestor.
The most obvious issue is that the information contained in the
OPTION_LQ_COOKIE option may be a key of some kind to the next
information that was to be returned to the requestor but did not fit
in the LEASEQUERY-REPLY message. By the time that the subsequent
LEASEQUERY message is received, however, that information may not be
supposed to be returned to the requestor. In this case, the DHCPv6
server MUST return the next OPTION_CLIENT_DATA option not already
returned to sender of the LEASEQUERY message that is beyond the "key"
in the OPTION_LQ_COOKIE.
In situations where ambiguity exists, the DHCPv6 server MAY return
duplicate information but SHOULD NOT make this a common occurrence --
or it will be possible for a query series to never terminate. The
DHCPv6 server MUST ensure that a query series will terminate and not
continue indefinitely.
The DHCPv6 server processing a LEASEQUERY message which contains an
OPTION_LQ_COOKIE MUST NOT return an error if the only problem with
the data in the OPTION_LQ_COOKIE option is that it refers to a
particular chunk of client data that is not now supposed to be
returned as a response to this LEASEQUERY. In this case, the DHCPv6
server MUST return the next available chunk of client data that
should now be returned from this LEASEQUERY. If these guidelines are
not followed, it would be possible to end up with a situation where a
series of LEASQUERY with OPTION_LQ_COOKIE option exchanges might
never terminate.
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If there is OPTION_CLIENT_DATA option information that was not sent
in the initial response to the LEASEQUERY message but which is now
available, but precedes the "key" in the OPTION_LQ_COOKIE option, the
DHCPv6 server SHOULD NOT return it. Likewise if there is information
that was returned in the initial response to the LEASEQUERY message
but which would not now be returned as a response from the identical
LEASEQUERY message, the DHCPv6 server SHOULD NOT do anything about
this.
5. Security Considerations
The senders of LEASEQUERY messages are expected to be within the same
security domain as the DHCPv6 server. As such, the security threat
to DHCPv6 leasequery is inherently an insider threat. However, this
document doesn't prohibit entities in external security domains from
sending LEASEQUERY messages to DHCPv6 servers. Regardless of the
network configuration, however, the potential attacks by insiders and
outsiders are the same.
If the requestor is an access concentrator, DHCPv6 leasequery
security SHOULD follow security between the relay agent and the
DHCPv6 server as described in [2] Sections 21.1 and 22.11.
Requestors are essentially a DHCPv6 client for the purposes of the
LEASEQUERY message. Thus, DHCPv6 authentication [2] is also an
appropriate mechanism for securing LEASEQUERY and LEASEQUERY-REPLY
messages.
Access concentrators are expected to be common leasequery requestors.
Access concentrators that use DHCPv6 gleaning (i.e., [9]), refreshed
with LEASEQUERY messages, will maintain accurate client/binding
information. This ensures that the access concentrator can forward
data traffic to the intended destination in the broadband access
network, can perform IPv6 source address verification of datagrams
from the access network, and can encrypt traffic that can only be
decrypted by the intended access modem (e.g., [BPI] and [BPI+]).
Thus, the LEASEQUERY message allows an access concentrator to provide
considerably enhanced security. DHCPv6 servers SHOULD prevent
exposure of their information (particularly the mapping of hardware
address to IPv6 address, which can be an invasion of broadband
subscriber privacy) by employing the techniques detailed in [2],
Section 21, "Authentication of DHCP Messages".
DHCPv6 servers SHOULD also provide for the ability to restrict the
information that they make via leasequery, as described in
Section 4.4.3.
DHCPv6 servers supporting LEASEQUERY SHOULD ensure that they cannot
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be successfully attacked by being flooded with large quantities of
LEASEQUERY messages in a short time. In some environments, it may be
appropriate to configure a DHCPv6 server with the IPv6 source
addresses of the relay agents for which it may respond to LEASEQUERY
messages, thereby allowing it to respond only to requests from only a
handful of relay agents. This does not provide any true security,
but may be useful to thwart unsophisticated attacks of various sorts.
Replayed messages can represent a DOS attack through exhaustion of
processing resources, bogus leasequery requestors can send a lot of
LEASEQUERY messages to overwhelm a DHCPv6 server, thus preventing the
server from serving legitimate and regular DHCPv6 clients as well as
legitimate DHCPv6 leasequery requestors, denying configurations to
legitimate DHCPv6 clients as well lease information to legitimate
DHCPv6 leasequery requestors.
One attack specific to an access concentrator as a requestor is the
establishment of a malicious server with the intent of providing
incorrect lease or route information to the access concentrator,
thwarting source IPv6 address verification and preventing correct
routing.
The use of the OPTION_SERVER_RSN option does provide an attacker that
also knows the server's DUID the ability to effectively lock out
future updates from the real server by supply a large sequence
number.
6. IANA Considerations
IANA is requested to assign the following new DHCPv6 Message types in
the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:
LEASEQUERY
LEASEQUERY-REPLY
IANA is requested to assign the following new DHCPv6 Option Codes in
the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:
OPTION_LQ_QUERY
OPTION_REPLY_SIZE
OPTION_LQ_COOKIE
OPTION_CLIENT_DATA
OPTION_CLT_TIME
IANA is requested to assign the following new DHCPv6 Status Codes in
the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters:
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UnknownQueryType
MalformedQuery
StaleCookie
TooShort
NotConfigured
NotAllowed
IANA is requested to create a new registry for the OPTION_LQ_QUERY
option query-type codes in the registry maintained in
http://www.iana.org/assignments/dhcpv6-parameters with the following
initial assignments:
QUERY_BY_CLIENTID 1
QUERY_BY_ADDRESS 2
QUERY_BY_PREFIX 3
QUERY_BY_LINK 4
QUERY_BY_REMOTE_ID 5
QUERY_BY_DEVICE_ID 6
7. Acknowledgements
Thanks to Ralph Droms, Richard Johnson, Josh Littlefield, Hemant
Singh, and Pak Siripunkaw for their input, ideas, and review during
the production of this document.
8. References
8.1. Normative References
[1] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[2] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C., and M.
Carney, "Dynamic Host Configuration Protocol for IPv6 (DHCPv6)",
RFC 3315, July 2003.
[3] Woundy, R. and K. Kinnear, "Dynamic Host Configuration Protocol
(DHCP) Leasequery", RFC 4388, February 2006.
[4] Troan, O. and R. Droms, "IPv6 Prefix Options for Dynamic Host
Configuration Protocol (DHCP) version 6", RFC 3633,
December 2003.
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8.2. Informative References
[5] Droms, R., "Dynamic Host Configuration Protocol", RFC 2131,
March 1997.
[6] Deering, S. and R. Hinden, "Internet Protocol, Version 6 (IPv6)
Specification", RFC 2460, December 1998.
[7] Volz, B., "DHCPv6 Relay Agent Remote ID Option
(draft-ietf-dhc-dhcpv6-remoteid-*)", March 2006.
[8] Droms, R., "DHCPv6 Device ID Option
(draft-droms-dhc-dhcpv6-deviceid-*)", June 2006.
[9] Droms, R., Volz, B., and O. Troan, "DHCP Relay Agent Assignment
Notification Option
(draft-ietf-dhc-dhcpv6-agentopt-delegate-*)", June 2006.
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Authors' Addresses
John Jason Brzozowski
Comcast Cable
1800 Bishops Gate Boulevard
Mt. Laurel, NJ 08054
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Kim Kinnear
Cisco Systems, Inc.
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Phone: +1 978 936 0000
Email: kkinnear@cisco.com
Bernard Volz
Cisco Systems, Inc.
1414 Massachusetts Ave.
Boxborough, MA 01719
USA
Phone: +1 978 936 0000
Email: volz@cisco.com
Shengyou Zeng
Cisco Systems, Inc.
1414 Massachusetts Ave.
Boxborough, MA 01719
USA
Phone: +1 978 936 0000
Email: szeng@cisco.com
Brzozowski, et al. Expires December 18, 2006 [Page 28]
Internet-Draft DHCPv6 Leasequery June 2006
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Brzozowski, et al. Expires December 18, 2006 [Page 29]