draft-ietf-dhc-leasequery-by-remote-id-02.txt   draft-ietf-dhc-leasequery-by-remote-id-03.txt 
DHC Working Group P. Kurapati DHC Working Group P. Kurapati
Internet-Draft R. Desetti Internet-Draft R. Desetti
Expires: January 14, 2010 B. Joshi Expires: April 29, 2010 B. Joshi
Infosys Technologies Ltd. Infosys Technologies Ltd.
July 13, 2009 October 26, 2009
DHCPv4 Leasequery by relay agent remote ID DHCPv4 Leasequery by relay agent remote ID
draft-ietf-dhc-leasequery-by-remote-id-02.txt draft-ietf-dhc-leasequery-by-remote-id-03.txt
Status of this Memo Status of this Memo
This Internet-Draft is submitted to IETF in full conformance with the This Internet-Draft is submitted to IETF in full conformance with the
provisions of BCP 78 and BCP 79. provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet- other groups may also distribute working documents as Internet-
Drafts. Drafts.
skipping to change at page 1, line 33 skipping to change at page 1, line 33
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 14, 2010. This Internet-Draft will expire on April 29, 2010.
Copyright Notice Copyright Notice
Copyright (c) 2009 IETF Trust and the persons identified as the Copyright (c) 2009 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents in effect on the date of Provisions Relating to IETF Documents in effect on the date of
publication of this document (http://trustee.ietf.org/license-info). publication of this document (http://trustee.ietf.org/license-info).
Please review these documents carefully, as they describe your rights Please review these documents carefully, as they describe your rights
skipping to change at page 2, line 21 skipping to change at page 2, line 21
agents to retrieve the lease information from the DHCP server as and agents to retrieve the lease information from the DHCP server as and
when this information is lost. Existing leasequery mechanism is data when this information is lost. Existing leasequery mechanism is data
driven which means that a relay agent can initiate the leasequery driven which means that a relay agent can initiate the leasequery
only when it starts receiving data from/to the clients. In certain only when it starts receiving data from/to the clients. In certain
scenarios, this model is not scalable. This document first looks at scenarios, this model is not scalable. This document first looks at
issues in existing mechanism and then proposes a new query type, issues in existing mechanism and then proposes a new query type,
query by remote ID, to address these issues. query by remote ID, to address these issues.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 6 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 5
3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 8 3. Motivation . . . . . . . . . . . . . . . . . . . . . . . . . . 7
4. Design Goals . . . . . . . . . . . . . . . . . . . . . . . . . 10 4. Design Goals . . . . . . . . . . . . . . . . . . . . . . . . . 9
4.1. Information Acquisition before Data Starts . . . . . . . . 10 4.1. Information Acquisition before Data Starts . . . . . . . . 9
4.2. Lessen Negative Caching . . . . . . . . . . . . . . . . . 10 4.2. Lessen Negative Caching . . . . . . . . . . . . . . . . . 9
4.3. Antispoofing in 'Fast Path' . . . . . . . . . . . . . . . 10 4.3. Antispoofing in 'Fast Path' . . . . . . . . . . . . . . . 9
5. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 11 5. Protocol Overview . . . . . . . . . . . . . . . . . . . . . . 10
6. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 13 6. Protocol Details . . . . . . . . . . . . . . . . . . . . . . . 11
6.1. Sending the DHCPLEASEQUERY Message . . . . . . . . . . . . 13 6.1. Sending the DHCPLEASEQUERY Message . . . . . . . . . . . . 11
6.2. Receiving the DHCPLEASEQUERY Message . . . . . . . . . . . 14 6.2. Receiving the DHCPLEASEQUERY Message . . . . . . . . . . . 12
6.3. Responding to the DHCPLEASEQUERY Message . . . . . . . . . 14 6.3. Responding to the DHCPLEASEQUERY Message . . . . . . . . . 12
6.4. Determining the IP address to be used in response . . . . 14 6.4. Determining the IP address to be used in response . . . . 12
6.5. Building a DHCPLEASEUNASSIGNED, DHCPLEASEUNKNOWN, or 6.5. Building a DHCPLEASEUNKNOWN or DHCPLEASEACTIVE Messages . 13
DHCPLEASEACTIVE Messages . . . . . . . . . . . . . . . . . 15 6.6. Sending a DHCPLEASEACTIVE or DHCPLEASEUNKNOWN Message . . 15
6.6. Sending a DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or 6.7. Receiving a DHCPLEASEACTIVE or DHCPLEASEUNKNOWN Message . 15
DHCPLEASEUNKNOWN Message . . . . . . . . . . . . . . . . . 17 6.8. Receiving No Response to the DHCPLEASEQUERY Message . . . 15
6.7. Receiving a DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or 6.9. Lease Binding Data Storage Requirements . . . . . . . . . 15
DHCPLEASEUNKNOWN Message . . . . . . . . . . . . . . . . . 17
6.8. Receiving No Response to the DHCPLEASEQUERY Message . . . 18
6.9. Lease Binding Data Storage Requirements . . . . . . . . . 18
6.10. Using the DHCPLEASEQUERY Message with Multiple DHCP 6.10. Using the DHCPLEASEQUERY Message with Multiple DHCP
Servers . . . . . . . . . . . . . . . . . . . . . . . . . 18 Servers . . . . . . . . . . . . . . . . . . . . . . . . . 16
7. RFC 4388 Considerations . . . . . . . . . . . . . . . . . . . 19 7. RFC 4388 Considerations . . . . . . . . . . . . . . . . . . . 17
8. Security Considerations . . . . . . . . . . . . . . . . . . . 20 8. Security Considerations . . . . . . . . . . . . . . . . . . . 18
9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 21 9. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 19
10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 22 10. Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . 20
11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
11.1. Normative Reference . . . . . . . . . . . . . . . . . . . 23 11.1. Normative Reference . . . . . . . . . . . . . . . . . . . 21
11.2. Informative Reference . . . . . . . . . . . . . . . . . . 23 11.2. Informative Reference . . . . . . . . . . . . . . . . . . 21
Appendix A. Why a New Leasequery is Required? . . . . . . . . . . 24 Appendix A. Why a New Leasequery is Required? . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 27 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 25
1. Introduction 1. Introduction
DHCP relay agents snoop DHCP messages and append relay agent DHCP relay agents snoop DHCP messages and append relay agent
information option before relaying it to the configured DHCP Servers. information option before relaying it to the configured DHCP Servers.
In this process, some relay agents also glean the lease information In this process, some relay agents also glean the lease information
sent by the server and maintain this locally. This information is sent by the server and maintain this locally. This information is
used for prevention of spoofing attempts from the clients and also used for prevention of spoofing attempts from the clients and also
sometimes used to install routing information. When relay agent sometimes used to install routing information. When relay agent
reboots, this information is lost. RFC 4388 [RFC4388] has defined a reboots, this information is lost. RFC 4388 [RFC4388] has defined a
skipping to change at page 11, line 25 skipping to change at page 10, line 25
Suppose that the access concentrator (e.g., DSLAM) lost the lease Suppose that the access concentrator (e.g., DSLAM) lost the lease
information when it was rebooted. When the access concentrator comes information when it was rebooted. When the access concentrator comes
up, it would initiate a DHCPLEASEQUERY message for each connection/ up, it would initiate a DHCPLEASEQUERY message for each connection/
circuit containing the Relay Agent Information option [RFC3046] with circuit containing the Relay Agent Information option [RFC3046] with
sub-option remote ID. DHCP server must return an IP address in the sub-option remote ID. DHCP server must return an IP address in the
ciaddr if it has any record of the client described by the remote ID. ciaddr if it has any record of the client described by the remote ID.
In the absence of specific configuration information to the contrary, In the absence of specific configuration information to the contrary,
it SHOULD be the IP address with the latest client-last-transaction- it SHOULD be the IP address with the latest client-last-transaction-
time associated with the client described by the remote ID. The DHCP time associated with the client described by the remote ID. The DHCP
servers that implement this document always send a response servers that implement this document always send a response
(DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or DHCPLEASEUNKNOWN) to the (DHCPLEASEACTIVE or DHCPLEASEUNKNOWN) to the DHCPLEASEQUERY message.
DHCPLEASEQUERY message. The reasons why a DHCPLEASEUNASSIGNED, The reasons why a DHCPLEASEACTIVE or DHCPLEASEUNKNOWN message might
DHCPLEASEACTIVE, or DHCPLEASEUNKNOWN message might be generated are be generated are explained in the specific query regimes below.
explained in the specific query regimes below. Servers that do not Servers that do not implement the DHCPLEASEQUERY based on remote ID
implement the DHCPLEASEQUERY based on remote ID message SHOULD simply message SHOULD simply not respond.
not respond.
The query regime is described below: The query regime is described below:
o Query by Agent Remote ID sub-option: o Query by Agent Remote ID sub-option:
For this query, the requester supplies only a option 82 which will For this query, the requester supplies only a option 82 which will
include only an Agent Remote ID sub-option in the DHCPLEASEQUERY include only an Agent Remote ID sub-option in the DHCPLEASEQUERY
message. The DHCP server will return any information that it has on message. The DHCP server will return any information that it has on
the IP address most recently accessed by a client with that Agent the IP address most recently accessed by a client with that Agent
Remote ID. In addition, it SHOULD supply any additional IP addresses Remote ID. In addition, it SHOULD supply any additional IP addresses
that have been associated with Agent Remote ID in different subnets. that have been associated with Agent Remote ID in different subnets.
Information about these bindings can then be found using the Query by Information about these bindings can then be found using the Query by
IP Address, as described in RFC 4388[RFC4388]. IP Address, as described in RFC 4388[RFC4388].
The DHCP server MUST reply with a DHCPLEASEACTIVE message if the The DHCP server MUST reply with a DHCPLEASEACTIVE message if the
Agent Remote ID in the DHCPLEASEQUERY message currently has an active Agent Remote ID in the DHCPLEASEQUERY message currently has an active
lease on an IP address in this DHCP server. The server MUST reply lease on an IP address in this DHCP server. Otherwise, the server
with a DHCPLEASEUNASSIGNED if it has information of the said remote MUST reply with a DHCPLEASEUNKNOWN message.
ID but no lease is assigned for the same. The server MAY keep track
of the remote ID values for which it has currently active leases as
well as any which it has served in the past but for which it has no
currently active leases. The server MUST reply with a
DHCPLEASEUNKNOWN message if it has no information of the said remote
ID.
6. Protocol Details 6. Protocol Details
In this section, DHCPLEASEQUERY message refers to DHCPLEASEQUERY In this section, DHCPLEASEQUERY message refers to DHCPLEASEQUERY
message with query by remote ID. message with query by remote ID.
6.1. Sending the DHCPLEASEQUERY Message 6.1. Sending the DHCPLEASEQUERY Message
The DHCPLEASEQUERY message is typically sent by an access The DHCPLEASEQUERY message is typically sent by an access
concentrator. The DHCPLEASEQUERY message uses the DHCP message concentrator. The DHCPLEASEQUERY message uses the DHCP message
format as described in RFC2131[RFC2131], and uses message number 10 format as described in RFC2131[RFC2131], and uses message number 10
in the DHCP Message Type option (option 53). The DHCPLEASEQUERY in the DHCP Message Type option (option 53). The DHCPLEASEQUERY
message has the following pertinent message contents: message has the following pertinent message contents:
o The giaddr MUST be set to the IP address of the requester (i.e., o The giaddr MUST be set to the IP address of the requester (i.e.,
the access concentrator). The giaddr is the return address of the the access concentrator). The giaddr is the return address of the
DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or DHCPLEASEUNKNOWN message DHCPLEASEACTIVE or DHCPLEASEUNKNOWN message from the DHCP server.
from the DHCP server. Note that this use of the giaddr is Note that this use of the giaddr is consistent with the definition
consistent with the definition of giaddr in RFC2131[RFC2131], of giaddr in RFC2131[RFC2131], where the giaddr is always used as
where the giaddr is always used as the return address of the DHCP the return address of the DHCP response message. In some (but not
response message. In some (but not all) contexts in RFC 2131, the all) contexts in RFC 2131, the address to allocate to a client is
giaddr is used as the "key" to access the appropriate address selected based on 'giaddr'.
pool.
o The Parameter Request List option (option 55) SHOULD be set to the o The Parameter Request List option (option 55) SHOULD be set to the
options of interest to the requester. It MUST include the Relay options of interest to the requester. It MUST include the Relay
Agent Information option (option 82). The other interesting Agent Information option (option 82). The other interesting
options are likely to include the IP Address Lease Time option options are likely to include the IP Address Lease Time option
(option 51), and possibly the Vendor class identifier option (option 51), and possibly the Vendor class identifier option
(option 60). In the absence of a Parameter Request List option, (option 60). In the absence of a Parameter Request List option,
the server SHOULD return the same options it would return for a the server SHOULD return the same options it would return for a
DHCPREQUEST message that didn't contain a DHCPLEASEQUERY message, DHCPREQUEST message that didn't contain Parameter Request List
which includes those mandated by Section 4.3.1 of [RFC2131] as option (option 55), which includes those mandated by Section 4.3.1
well as any options that the server was configured to always of [RFC2131] as well as any options that the server was configured
return to a client. to always return to a client.
Additional details concerning different query types are Additional details concerning different query types are
o Query by Agent Remote ID sub-option: o Query by Agent Remote ID sub-option:
* There MUST be a Relay Agent Information option (option 82) with * There MUST be a Relay Agent Information option (option 82) with
only Agent Remote ID sub-option (sub-option 2) in the only Agent Remote ID sub-option (sub-option 2) in the
DHCPLEASEQUERY message. DHCPLEASEQUERY message.
* The "ciaddr" field MUST be set to zero. * The "ciaddr" field MUST be set to zero.
skipping to change at page 14, line 25 skipping to change at page 12, line 22
6.2. Receiving the DHCPLEASEQUERY Message 6.2. Receiving the DHCPLEASEQUERY Message
A DHCPLEASEQUERY message MUST have a non-zero giaddr. The A DHCPLEASEQUERY message MUST have a non-zero giaddr. The
DHCPLEASEQUERY message MUST have a zero ciaddr, a zero htype/hlen/ DHCPLEASEQUERY message MUST have a zero ciaddr, a zero htype/hlen/
chaddr, and no Client-identifier option. The DHCPLEASEQUERY message chaddr, and no Client-identifier option. The DHCPLEASEQUERY message
MUST have a relay agent option 82 with only remote ID sub-option. MUST have a relay agent option 82 with only remote ID sub-option.
6.3. Responding to the DHCPLEASEQUERY Message 6.3. Responding to the DHCPLEASEQUERY Message
There are three possible responses to a DHCPLEASEQUERY message: There are two possible responses to a DHCPLEASEQUERY message:
o DHCPLEASEUNASSIGNED
The server MUST respond with a DHCPLEASEUNASSIGNED message if this
server has information about the remote ID, but there is no
associated active lease. The DHCPLEASEUNASSIGNED indicates that the
server manages the IP address allocation for the given remote ID, but
there is no currently active lease.
o DHCPLEASEUNKNOWN o DHCPLEASEUNKNOWN
The DHCPLEASEUNKNOWN message indicates that the client specified in The DHCPLEASEUNKNOWN message indicates that the client specified in
the DHCPLEASEQUERY message is not managed by the server. the DHCPLEASEQUERY message is not allocated any lease or it is not
managed by the server.
o DHCPLEASEACTIVE o DHCPLEASEACTIVE
The DHCPLEASEACTIVE message indicates that the server not only knows The DHCPLEASEACTIVE message indicates that the server not only knows
the client specified in the DHCPLEASEQUERY message, but also knows the client specified in the DHCPLEASEQUERY message, but also knows
that there is an active lease for that client. that there is an active lease for that client.
6.4. Determining the IP address to be used in response 6.4. Determining the IP address to be used in response
Since the response to a DHCPLEASEQUERY request can only contain full Since the response to a DHCPLEASEQUERY request can only contain full
skipping to change at page 15, line 28 skipping to change at page 13, line 18
If there is only a single IP address that fulfills this criteria, If there is only a single IP address that fulfills this criteria,
then it MUST be placed in the "ciaddr" field of the DHCPLEASEACTIVE then it MUST be placed in the "ciaddr" field of the DHCPLEASEACTIVE
message. message.
In the case where more than one IP address has been accessed by the In the case where more than one IP address has been accessed by the
client specified by the Remote ID, then the DHCP server MUST return client specified by the Remote ID, then the DHCP server MUST return
the IP address returned to the client in the most recent transaction the IP address returned to the client in the most recent transaction
with the client unless the DHCP server has been configured by the with the client unless the DHCP server has been configured by the
server administrator to use some other preference mechanism. server administrator to use some other preference mechanism.
6.5. Building a DHCPLEASEUNASSIGNED, DHCPLEASEUNKNOWN, or 6.5. Building a DHCPLEASEUNKNOWN or DHCPLEASEACTIVE Messages
DHCPLEASEACTIVE Messages
DHCPLEASEUNASSIGNED and DHCPLEASEUNKNOWN messages are created alike For a DHCPLEASEUNKNOWN message, DHCP server MUST echo the received
except for message type. DHCP server MUST echo the received Option Option 82 available in DHCPLEASEQUERY in the response. No other
82 available in DHCPLEASEQUERY in the response. No other options are options are returned for this message. With that the processing for
returned for these messages. With that the processing for a a DHCPLEASEUNKNOWN message is complete.
DHCPLEASEUNASSIGNED or DHCPLEASEUNKNOWN message is complete.
For the DHCPLEASEACTIVE message, the rest of the processing largely For the DHCPLEASEACTIVE message, the rest of the processing largely
involves returning information about the IP address specified in the involves returning information about the IP address specified in the
"ciaddr" field. "ciaddr" field.
The MAC address of the DHCPLEASEACTIVE message MUST be set to the The MAC address of the DHCPLEASEACTIVE message MUST be set to the
values that identify the client associated with the IP address in the values that identify the client associated with the IP address in the
"ciaddr" field of the DHCPLEASEACTIVE message. "ciaddr" field of the DHCPLEASEACTIVE message.
If the Client-identifier option (option 61) is specified in the If the Client-identifier option (option 61) is specified in the
skipping to change at page 17, line 13 skipping to change at page 15, line 5
specified, above). specified, above).
In the event that two servers are cooperating to provide a high- In the event that two servers are cooperating to provide a high-
availability DHCP server, as supported by [RFC2131], they would have availability DHCP server, as supported by [RFC2131], they would have
to communicate some information about IP address bindings to each to communicate some information about IP address bindings to each
other. In order to properly support the DHCPLEASEQUERY message, other. In order to properly support the DHCPLEASEQUERY message,
these servers MUST ensure that they communicate the Relay Agent these servers MUST ensure that they communicate the Relay Agent
Information option information to each other in addition to any other Information option information to each other in addition to any other
IP address binding information. IP address binding information.
6.6. Sending a DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or 6.6. Sending a DHCPLEASEACTIVE or DHCPLEASEUNKNOWN Message
DHCPLEASEUNKNOWN Message
The server expects a giaddr in the DHCPLEASEQUERY message, and The server expects a giaddr in the DHCPLEASEQUERY message, and
unicasts the DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or unicasts the DHCPLEASEACTIVE or DHCPLEASEUNKNOWN message to the
DHCPLEASEUNKNOWN message to the giaddr. giaddr.
6.7. Receiving a DHCPLEASEUNASSIGNED, DHCPLEASEACTIVE, or 6.7. Receiving a DHCPLEASEACTIVE or DHCPLEASEUNKNOWN Message
DHCPLEASEUNKNOWN Message
When a DHCPLEASEACTIVE message is received in response to the When a DHCPLEASEACTIVE message is received in response to the
DHCPLEASEQUERY message, it means that there is a currently active DHCPLEASEQUERY message, it means that there is a currently active
lease for this IP address in this DHCP server. The access lease for this IP address in this DHCP server. The access
concentrator SHOULD use the information in the "htype", "hlen", and concentrator SHOULD use the information in the "htype", "hlen", and
"chaddr" fields of the DHCPLEASEACTIVE as well as Relay Agent "chaddr" fields of the DHCPLEASEACTIVE as well as Relay Agent
Information option information included in the packet to refresh its Information option information included in the packet to refresh its
location information for this IP address. An access concentrator is location information for this IP address. An access concentrator is
likely to query by IP address for all the IP addresses specified in likely to query by IP address for all the IP addresses specified in
the associated-ip option in the response, if any, at this point in the associated-ip option in the response, if any, at this point in
time. time.
When a DHCPLEASEUNASSIGNED message is received in response to the
DHCPLEASEQUERY message, it means that there is currently no active
lease associated with the client specified by remote ID in the DHCP
server, but that this server does in fact manage the IP address
allocation for the client specified by remote ID. Access
Concentrator MAY store this information for future use.
When a DHCPLEASEUNKNOWN message is received by an access concentrator When a DHCPLEASEUNKNOWN message is received by an access concentrator
that has sent out a DHCPLEASEQUERY message, it means that the DHCP that had sent out a DHCPLEASEQUERY message, it means that the DHCP
server does not have definitive information concerning the DHCP server does not have definitive information concerning the DHCP
client specified in the Agent Remote ID sub-option of the client specified in the Agent Remote ID sub-option of the
DHCPLEASEQUERY message. The Access Concentrator MAY store this DHCPLEASEQUERY message. The access concentrator MAY store this
information for future use. However, a DHCPLEASEQUERY SHOULD NOT be information for future use. However, a DHCPLEASEQUERY SHOULD NOT be
attempted with the same Remote ID sub-option. attempted with the same Remote ID su-option.
In both the cases above, the impact of negative caching is greatly For leasequry by remote-id, the impact of negative caching is greatly
reduced as the leasequery by remote-id leads to "definitive" and reduced as the the response leads to "definitive" information on all
complete information on all the hosts connected through a connection. the hosts connected behind the connection. Note that in the case of
Note that in the case of RFC 4388 [RFC4388], a host spoofing several RFC 4388 [RFC4388], a host spoofing several IP addresses can lead to
IP addresses can lead to negative caching of greater magnitude. negative caching of greater magnitude. Another important change this
draft brings is the removal of "periodic" leasequeries generated from
negative caching caused by DHCPLEASEUNKNOWN. Since the information
obtained through query by remote-id is complete, there is no need of
attempting leasequery again for the same remote-id.
6.8. Receiving No Response to the DHCPLEASEQUERY Message 6.8. Receiving No Response to the DHCPLEASEQUERY Message
When an access concentrator receives no response to a DHCPLEASEQUERY When an access concentrator receives no response to a DHCPLEASEQUERY
message, it should be handled in the same manner as suggested in RFC message, it should be handled in the same manner as suggested in RFC
4388 [RFC4388]. 4388 [RFC4388].
6.9. Lease Binding Data Storage Requirements 6.9. Lease Binding Data Storage Requirements
IMPLEMENTATION: IMPLEMENTATION:
skipping to change at page 19, line 20 skipping to change at page 17, line 20
provided it uses RFC 4388 [RFC4388] defined query types. Also, a provided it uses RFC 4388 [RFC4388] defined query types. Also, a
server supporting this document can work with a client not supporting server supporting this document can work with a client not supporting
this query type. However, there are some changes that this document this query type. However, there are some changes that this document
proposes with respect to RFC 4388 [RFC4388]. Implementors extending proposes with respect to RFC 4388 [RFC4388]. Implementors extending
RFC 4388 [RFC4388] implementation to support this document, should RFC 4388 [RFC4388] implementation to support this document, should
take note of the following points: take note of the following points:
o RFC 4388 [RFC4388] suggests that a DHCPLEASEUNASSIGNED is returned o RFC 4388 [RFC4388] suggests that a DHCPLEASEUNASSIGNED is returned
only in the case of 'query by IP address'. All other query types only in the case of 'query by IP address'. All other query types
will have a return message of either DHCPLEASEACTIVE or will have a return message of either DHCPLEASEACTIVE or
DHCPLEASEUNKNOWN'. This document proposes that DHCPLEASEUNKNOWN'. Although it is possible to return
DHCPLEASEUNASSIGNED can be returned for the query by remote ID. DHCPLEASEUNASSIGNED in case of a query by remote-id, in order to
maintain compatibility with other similar query types (MAC and
Client-id) a query by remote-id does not support a
DHCPLEASEUNASSIGNED response.
o There may be cases where a query by IP address/MAC address/Client o There may be cases where a query by IP address/MAC address/Client
Identifier has an option 82 containing remote ID. In that case, Identifier has an option 82 containing remote ID. In that case,
the query will still be recognized as query by IP address/MAC the query will still be recognized as query by IP address/MAC
address/Client Identifier as specified by RFC 4388 [RFC4388]. address/Client Identifier as specified by RFC 4388 [RFC4388].
o Section 6.4 of RFC 4388 [RFC4388] suggests that a DHCPLEASEUNKNOWN o Section 6.4 of RFC 4388 [RFC4388] suggests that a DHCPLEASEUNKNOWN
MUST NOT have any other option present. But for a query by remote MUST NOT have any other option present. But for a query by remote
ID, option 82 MUST be present in the reply. ID, option 82 MUST be present in the reply.
 End of changes. 23 change blocks. 
100 lines changed or deleted 78 lines changed or added

This html diff was produced by rfcdiff 1.37a. The latest version is available from http://tools.ietf.org/tools/rfcdiff/