Internet DRAFT - draft-zhou-dhc-gre-option
draft-zhou-dhc-gre-option
DHC WG X. Zhou
Internet-Draft ZTE Corporation
Intended status: Standards Track October 11, 2012
Expires: April 14, 2013
DHCPv4 and DHCPv6 options for GRE
draft-zhou-dhc-gre-option-00
Abstract
This document specifies how the Generic Routing Encapsulation
parameters are exchanged using Dynamic Host Configuration Protocol
(DHCPv4 and DHCPv6) signaling in an IP network.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress."
This Internet-Draft will expire on April 14, 2013.
Copyright Notice
Copyright (c) 2012 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Zhou Expires April 14, 2013 [Page 1]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention and Terminology . . . . . . . . . . . . . . . . . . 4
3. GRE Key Option for DHCPv4 . . . . . . . . . . . . . . . . . . 5
4. GRE Key Option for DHCPv6 . . . . . . . . . . . . . . . . . . 6
5. Option Usage . . . . . . . . . . . . . . . . . . . . . . . . . 7
5.1. Usage of GRE Key Option for DHCPv4 . . . . . . . . . . . . 7
5.1.1. Mobile Node Behavior . . . . . . . . . . . . . . . . . 7
5.2. Usage of GRE Key Option for DHCPv6 . . . . . . . . . . . . 7
5.2.1. Mobile Node Behavior . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . 9
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
8. Normative References . . . . . . . . . . . . . . . . . . . . . 11
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 12
Zhou Expires April 14, 2013 [Page 2]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
1. Introduction
There are scenarios where the point-to-point access link types are
required to be supported. For example, Proxy Mobile IPv6 [RFC5213]
supports only point-to-point access link types which assumes that the
mobile node and mobile access gateway are the only two nodes on the
access link. In this case, both IP layer and layer-2 point-to-point
can be used for this requirement. When there is IP routed node being
deployed between the two point-to-point nodes, only IP layer point-
to-point mode can be used. In this case, Generic Routing
Encapsulation (GRE) [RFC2784] is one of ideal IP layer modes which
can be used to implementate layer-3 point-to-point link. In other
hand, DHCP is widely used to assign configuration parameters in
addtion to IP address.
This document defines new Dynamic Host Configuration Protocol (DHCPv4
and DHCPv6) options to enable a mobile node to obtain the dynamically
assigned Generic Routing Encapsulation key. In this way, the mobile
node achieves to negotiate the uplink/downlink GRE key via DHCP
signaling. In this specification, it assumes that the DHCP server
makes sure the corresponding GRE tunnel endpoint can obtain the
negotiated GRE key if DHCP server is not co-located with the
corresponding GRE tunnel endpoint.
Zhou Expires April 14, 2013 [Page 3]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
2. Convention and 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 [RFC2119].
The following term used in this document.
Uplink GRE Key
The GRE key is assigned by the DHCP server and used by the mobile
node, i.e. DHCP client to mark the uplink traffic that belongs to
a specific IP connection as described in this specification.
Downlink GRE Key
The GRE key is assigned by the DHCP client and used by the
corresponding GRE tunnel endpoint to mark the downlink traffic
that belongs to a specific IP connection as described in this
specification. In current specification, it is optional for the
mobile node i.e. DHCP client side to assign the downlink GRE key.
If the DHCP cilent does not set the value of the downlink GRE key
in the option, it is considered that the value of the downlink GRE
key is equal to the value of uplink GRE key by default.
Thus, both the uplink GRE key and downlink GRE key are used to
identify the specific IP connection which are unique within the scope
of the DHCP client side.
Zhou Expires April 14, 2013 [Page 4]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
3. GRE Key Option for DHCPv4
This section describes the GRE Key Option for DHCPv4. The option
layout is depicted 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 Code | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GRE Key Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option Code
OPTION-IPv4_GREKEY(To be assigned).
Length
8-bit unsigned integer indicating the length of the option in
octets, excluding the Option Code and length fields.
GRE Key Identifier
A four-byte field containing the GRE key identifier as specified
in [RFC2890].
Zhou Expires April 14, 2013 [Page 5]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
4. GRE Key Option for DHCPv6
This section describes the GRE Key Option for DHCPv6. The option
layout is depicted 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 Code | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| GRE Key Identifier |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
. .
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Option Code
OPTION-IPv6_GREKEY(To be assigned).
Length
16-bit unsigned integer indicating the length of the option in
octets, excluding the Option Code and length fields.
GRE Key Identifier
A four-byte field containing the GRE key identifier as specified
in [RFC2890].
Zhou Expires April 14, 2013 [Page 6]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
5. Option Usage
5.1. Usage of GRE Key Option for DHCPv4
The requesting and sending of the proposed DHCPv4 options follow the
rules for DHCP options in [RFC2131].
5.1.1. Mobile Node Behavior
In order to request for GRE Key exchanging, the mobile node (i.e.
DHCP client) MUST include a GRE Key option in the Parameter Request
List (PRL) in the respective DHCP messages as defined in [RFC2131]
and [RFC2132]. The DHCP client MAY initiate a new DHCP exchange or
piggyback on other DHCP message exchanges. DHCP client-handling PRL
options are specified in [RFC2131], Section 4.4.
If the mobile node include GRE Key option and set 0 in the GRE Key
identifier field, it indicates that the downlink GRE key has the same
value with the uplink GRE key. If the mobile node include GRE Key
option and set non-zero in the GRE Key identifier field, it
explicitly assigns the downlink GRE key to the corresponding GRE
tunnel endpoint. In this specification, the GRE Key identifier field
is set 0 by default.
If the mobile node receives the DHCP message sent by the DHCPv4
server without GRE key option, the mobile node MUST consider that the
DHCPv4 server does not support the GRE Key option and MUST not
include the GRE Key option in the subsequent DHCPv4 message.
5.2. Usage of GRE Key Option for DHCPv6
The requesting and sending of the proposed DHCPv6 options follow the
rules for DHCP options in [RFC3315].
5.2.1. Mobile Node Behavior
In order to request for GRE Key exchanging, the mobile node (i.e.
DHCP client) MUST include a GRE Key option in the Option Request
Option (ORO) in the respective DHCP messages as defined in [RFC3315].
The DHCP client MAY initiate a new DHCP exchange or piggyback on
other DHCP message exchanges. DHCP client-handling ORO options are
specified in [RFC3315], Section 17.1 and 18.1.
If the mobile node include GRE Key option and set 0 in the GRE Key
identifier field, it indicates that the downlink GRE key has the same
value with the uplink GRE key. If the mobile node include GRE Key
option and set non-zero in the GRE Key identifier field, it
explicitly assigns the downlink GRE key to the corresponding GRE
Zhou Expires April 14, 2013 [Page 7]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
tunnel endpoint. In this specification, the GRE Key identifier field
is set 0 by default.
If the mobile node receives the DHCP message sent by the DHCPv6
server without GRE key option, the mobile node MUST consider that the
DHCPv6 server does not support the GRE Key option and MUST not
include the GRE Key option in the subsequent DHCPv6 message.
Zhou Expires April 14, 2013 [Page 8]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
6. Security Considerations
TBD
Zhou Expires April 14, 2013 [Page 9]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
7. IANA Considerations
This document defines two new DHCP options as described in Sections 3
and 4.
GRE Key Option for DHCPv4(OPTION-IPv4_GREKEY) TBA
GRE Key Option for DHCPv6 (OPTION-IPv6_GREKEY) TBA
Zhou Expires April 14, 2013 [Page 10]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
8. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2131] Droms, R., "Dynamic Host Configuration Protocol",
RFC 2131, March 1997.
[RFC2132] Alexander, S. and R. Droms, "DHCP Options and BOOTP Vendor
Extensions", RFC 2132, March 1997.
[RFC2784] Farinacci, D., Li, T., Hanks, S., Meyer, D., and P.
Traina, "Generic Routing Encapsulation (GRE)", RFC 2784,
March 2000.
[RFC2890] Dommety, G., "Key and Sequence Number Extensions to GRE",
RFC 2890, September 2000.
[RFC3315] Droms, R., Bound, J., Volz, B., Lemon, T., Perkins, C.,
and M. Carney, "Dynamic Host Configuration Protocol for
IPv6 (DHCPv6)", RFC 3315, July 2003.
[RFC5213] Gundavelli, S., Leung, K., Devarapalli, V., Chowdhury, K.,
and B. Patil, "Proxy Mobile IPv6", RFC 5213, August 2008.
Zhou Expires April 14, 2013 [Page 11]
Internet-Draft DHCPv4 and DHCPv6 options for GRE October 2012
Author's Address
Xingyue Zhou
ZTE Corporation
No.50 Software Avenue, Yuhuatai District
Nanjing
China
Phone: +86-25-8801-4634
Email: zhou.xingyue@zte.com.cn
Zhou Expires April 14, 2013 [Page 12]
