dhc G. Liu
Internet-Draft Y. Tu
Intended status: Standards Track C. Zhu
Expires: September 12, 2013 ZTE Corporation
W. Hendericks
D. Derksen
L. Thiebaut
Alcatel-Lucent
March 11, 2013
DHCP Options for 3GPP Service
draft-liu-dhc-3gpp-option-03.txt
Abstract
This document defines a new option that can be used by DHCP clients
in their signaling sent to DHCP servers, when those clients need to
associate a request for an IP address or IPv6 prefix with a given
3GPP packet service.It is intended for scenarios of interworking
between a non-3GPP access and a 3GPP network.
Status of this Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on September 12, 2013.
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Convention & Terminology . . . . . . . . . . . . . . . . . . . 4
3. Problem Statement . . . . . . . . . . . . . . . . . . . . . . 5
4. 3GPP-Service Option Format . . . . . . . . . . . . . . . . . . 6
4.1. APN Sub-option Format . . . . . . . . . . . . . . . . . . 7
4.2. Non Seamless WLAN Offload
(3GPP-Service-Type)Sub-option Format . . . . . . . . . . . 7
5. DHCP Client Behavior . . . . . . . . . . . . . . . . . . . . . 10
6. DHCP Server Behavior . . . . . . . . . . . . . . . . . . . . . 11
7. Security Considerations . . . . . . . . . . . . . . . . . . . 12
8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
9. Normative References . . . . . . . . . . . . . . . . . . . . . 14
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 15
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1. Introduction
The Dynamic Host Configuration Protocol (DHCP) is built on a client-
server model, where designated DHCP server allocate network addresses
and deliver configuration parameters to dynamically configured hosts.
The changes to [RFC2131][RFC3315] defined in this document defines
the use of 3GPP specific option transferred to DHCP server by DHCP
client.
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2. Convention & 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 [RFC 2119].
The terminology in this document is based on the definitions in
[RFC2131][RFC3315], in addition to the ones specified in this section
3GPP 3rd Generation Partnership Project
TS Technical Specification
EPC Evolved Packet Core
APN Access Point Name
PDN Packet Data Network
GTP GPRS Tunnelling Protocol
PMIP Proxy Mobile IP
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3. Problem Statement
In 3GPP TS 23.402, 3GPP UE can access the 3GPP EPC through non-3GPP
IP access.
When the non 3GPP access is Trusted, there is no need for the 3GPP UE
to establish a Layer 3 tunnel (IPSec [RFC4301], DSMIPv6 [RFC 5555])
to access the EPC as it can rely upon the non 3GPP access security
mechanisms. In this case, the 3GPP UE may send DHCP signaling to non
3GPP access to acquire an IP address. However, the 3GPP UE may wish
to associate its request for an IP address with IP services provided
by the 3GPP EPC or may conversely explicitly require that its traffic
is not sent to the EPC but offloaded, even though the UE has been
authenticated via its 3GPP credentials (the service is called "NSO"
i.e. Non Seamless Offload).
The APN (Access Point Name) is the parameter by which a 3GPP UE
signals the kind of EPC service it desires. Based on the value of
this parameter, a 3GPP IP Edge (a PDN GW) is selected and the PDN GW
is able to determine the IP features to deliver to the traffic
exchanged by the UE as part of this APN.
It should be noted that the set of IP configuration parameters that
the UE may receive via a DHCP response (e.g. the DNS server(s)
address) may also be influenced by the value of the APN.
Thus when requesting an IP address via DHCP, a 3GPP UE should be able
to indicate:
o Whether this IP address is for NSO or whether it is for an EPC
service.
o If the IP address is for an EPC service, the value of the APN
corresponding to the IP services reached when using this IP address.
The UE may also request an EPC service without providing an APN
value; in this case, the network uses a default APN value.
Such DHCP request may be sent when the UE requests access to EPC via
non 3GPP access, or when the UE performs mobility from a 3GPP access
to a non 3GPP access.
This document is intended to define a new DHCP option for "3GPP
Service".
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4. 3GPP-Service Option Format
A DHCP client within a 3GPP based device sets the "3GPP-Service"
Option in the DHCP request it sends to the network to indicate the
desired 3GPP service associated with that request.
A DHCP server willing to indicate it has taken into account the
parameters / sub-options of a "3GPP-Service" Option included by the
client in a DHCP request mirrors these parameters in the DHCP
signaling it sends back to the client.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 3GPP-SERVICE | option-length | sub-options...
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1: 3GPP Service Option Format for DHCPv4
option-code 3GPP-Service (TBD)
option-len The number of octets in the option, minimum 1.
Sub-options The "3GPP-Service" Option may contain one or more Sub-options further defined in this document
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| 3GPP-SERVICE | option-length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| sub-options | -
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2: 3GPP Service Option Format for DHCPv6
option-code 3GPP-Service (TBD)
option-len The number of octets in the option, minimum 1.
Sub-options The "3GPP-Service" Option may contain one or more Sub-options further defined in this document
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4.1. APN Sub-option Format
The purpose of 3GPP-APN (Access Point Name) Sub-option is sent by UE
to network for identifing the packet data network associated with the
DHCP message. The APN is defined in 3GPP TS 23.401[TS23401].
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Length | Value
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 3: APN Sub-option Format for DHCPv4
Code 3GPP-APN(TBD).
Length The number of octets in the option, minimum 1.
Value The APN value, as defined in 3GPP TS 24.008 [TS24008] section 10.5.6.1.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | Length |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| value |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4: APN Sub-option Format for DHCPv6
Code 3GPP-APN(TBD).
Length The number of octets in the option, minimum 1.
Value The APN value, as defined in 3GPP TS 24.008 [TS24008] section 10.5.6.1.
The 3GPP-APN Sub-option SHOULD only be present once in a DHCP
message. If it is present more than once, the value of the last
occurrence of the option supersedes the value of the other
occurrences of this sub-option.
4.2. Non Seamless WLAN Offload (3GPP-Service-Type)Sub-option Format
The purpose of 3GPP-Service-Type (Non Seamless Offload) Sub-option is
to identify whether the DHCP message is to be associated with a Non
Seamless Offload service or with an EPC service.
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The 3GPP Non Seamless Offload service is defined in 3GPP TS 23.402
[TS23402].
0
0 1 2 3 4 5 6 7 8 9
+-+-+-+-+-+-+-+-+-+-+
| Code |S| V |
+-+-+-+-+-+-+-+-+-+-+
Figure 5: 3GPP-Service-Type Sub-option Format for DHCPv4
Code 3GPP-Service-Type (TBD).
S Bit 4 of octet 1 is spare and shall be coded as zero.
V The 3GPP-Service-Type value, the defination is as follows,
Bits 0 1
0 1 NSO
0 0 EPC
All other values are reserved.
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
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Code | S |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| V |
+-+-+
Figure 6: 3GPP-Service-Type Sub-option Format for DHCPv6
Code 3GPP-Service-Type (TBD).
S This is spare and shall be coded as zero.
V The 3GPP-Service-Type value, the defination of is as follows,
Bits 0 1
0 1 NSO
0 0 EPC
All other values are reserved.
The presence of the 3GPP-Service-Type Sub-option in a DHCP message
indicates whether the DHCP signalling is associated with a NSO
service or an EPC service rendered to the UE.
The 3GPP-Service-Type Sub-option SHOULD NOT be provided in the same
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DHCP message than the 3GPP-APN Sub-option, when the 3GPP-Service-Type
sub-option includes NSO indication. If present, the 3GPP-APN Sub-
option SHOULD be provided in the same DHCP message than the 3GPP-
Service-Type Sub-option, when the 3GPP-Service-Type sub-option
includes EPC indication. NSO indication and EPC indication are
exclusive.
If the 3GPP-Service-Type Sub-option includes NSO indication, and if
3GPP-APN Sub-option is included, the 3GPP-APN Sub-option is ignored.
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5. DHCP Client Behavior
For DHCPv4 protocol, a DHCP client may include a "3GPP-Service"
option in the option payload of DHCPDISCOVER and DHCP REQUEST
messages being sent toward a DHCP server in order to associate its
request with IP services provided by the 3GPP EPC or to explicitly
require that its traffic is not sent to the EPC but offloaded
For DHCPv6 protocol, DHCP client may include a "3GPP-Service" option
in the option payload of SOLICIT message being sent toward a DHCP
server in order to associate its request with IP services provided by
the 3GPP EPC or to explicitly require that its traffic is not sent to
the EPC but offloaded.
If the answer from the DHCP server does not include a "3GPP-Service"
option, the DHCP client assumes that the answer is not associated
with an EPC service.
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6. DHCP Server Behavior
A DHCP server that receives a "3GPP-Service" option from a DHCP
client but does not support this option, MUST ignore this option and
MUST NOT provide this option in the signaling it sends back towards
the DHCP client.
Conversely, when a DHCP server has taken this option into account it
MUST provide this option in the signaling it sends back towards the
DHCP client.
A DHCP server supporting this option SHOULD take the content of this
option into account when trying to serve the DHCP client. This may
involve making sure relevant signaling (e.g. GTP,PMIP [RFC5213]) is
sent to an EPC gateway determined using the parameters of the "3GPP-
Service" option.
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7. Security Considerations
Security considerations in DHCPv4 are described in [RFC3118].
Security considerations in DHCPv6 are described in [RFC3315].
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8. IANA Considerations
IANA is requested to assign one new DHCP option code defined in
section 5.
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9. 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.
[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.
[TS23401] 3GPP, "General Packet Radio Service (GPRS) enhancements
for Evolved Universal Terrestrial Radio Access Network(E-
UTRAN) access", 2011.
[TS23402] 3GPP, "Architecture enhancements for non-3GPP accesses",
2011.
[TS24008] 3GPP, "Mobile radio interface Layer 3 specification; Core
network protocols", 2010.
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Authors' Addresses
Guoyan Liu
ZTE Corporation
No.68 Zijinghua Avenue, Yuhuatai District
Nanjing
China
Phone: +86-25-5287-1362
Email: liu.guoyan@zte.com.cn
Yangwei Tu
ZTE Corporation
No.68 Zijinghua Avenue, Yuhuatai District
Nanjing
China
Phone: +86-25-5287-1362
Email: tu.yangwei@zte.com.cn
Chunhui Zhu
ZTE Corporation
No.68 Zijinghua Avenue, Yuhuatai District
Nanjing
China
Phone: +86-25-5287-4634
Email: zhu.chunhui@zte.com.cn
Wim Hendericks
Alcatel-Lucent
Email: Wim.Henderickx@alcatel-lucent.com
Daniel Derksen
Alcatel-Lucent
Email: Daniel.Derksen@alcatel-lucent.com
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Laurent Thiebaut
Alcatel-Lucent
Email: laurent.thiebaut@alcatel-lucent.com
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