Network Working Group L. Xue Internet-Draft B. Sarikaya Intended status: Informational Huawei Expires: August 29, 2013 February 25, 2013 DHCP option for STA Location Information draft-xue-dhc-location-option-01 Abstract This document introduces WTP information transported using DHCPv4/v6. In this procedure, DHCPv4/v6 snooping is deployed on the WTP node or AC node. Then the WTP information can be inserted into the extension option of DHCPv4/v6 message. GW obtain the WTP information of the subscriber through which the subscriber accesses network. Requirements Language 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 [RFC2119]. 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 August 29, 2013. Copyright Notice Copyright (c) 2013 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 Xue & Sarikaya Expires August 29, 2013 [Page 1] Internet-Draft sta location via DHCP February 2013 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. Table of Contents 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1.1. Terminology . . . . . . . . . . . . . . . . . . . . . . . 4 2. Applicability . . . . . . . . . . . . . . . . . . . . . . . . 5 3. DHCPv4/v6 Operation . . . . . . . . . . . . . . . . . . . . . 6 3.1. DHCPv4 Operation . . . . . . . . . . . . . . . . . . . . . 6 3.2. DHCPv6 Operation . . . . . . . . . . . . . . . . . . . . . 7 4. Location Information Option . . . . . . . . . . . . . . . . . 8 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 9 6. Security Considerations . . . . . . . . . . . . . . . . . . . 10 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 10 7.1. Normative References . . . . . . . . . . . . . . . . . . . 10 7.2. Informative References . . . . . . . . . . . . . . . . . . 10 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 10 Xue & Sarikaya Expires August 29, 2013 [Page 2] Internet-Draft sta location via DHCP February 2013 1. Introduction WLAN (Wireless Local Area Network) features low cost and flexible, and even high speed wireless data access with open spectrum. So it is becoming very popular these years. Especially, it is a general case that currently WLAN is used to supplement cellular (2G/3G/LTE) network. This provides a good chance for operators to offer broadband service with less CAPEX. Traditionally, WLAN consists of WTP and AC device as optional. WTP is the physical or logical network entity that contains an RF antenna and wireless physical layer (PHY) to transmit and receive station traffic for wireless access networks, and then transmit the packet to the wireline network. It works as media converter. There are two kinds of WTP in exiting network, defined as standalone WTP and Controlled WTP. The standalone WTP refers to the WTP in autonomous WLAN architecture. Here standalone WTP response for all WLAN functionality, such as encryption/decryption, authentication, etc. Instead, controlled WTP refers to the WTP in centralized WLAN architecture. In this case, WTP management and subscriber authentication are implemented on AC device. It is possible that AC isn't intelligent enough to aggregate all the WLAN critical functions in one, because the AC device is always enterprise device instead of carrier device. It is costly in large- scale intelligent AC deployment, also it is challenge for operators. So it is a popular scenario to split the authentication function from AC to Gateway(GW), which is the existing authentication gateway for other service, such as PPP, etc. This enables a better environment that diminishes the software and hardware upgrade for operators, shown in figure 1. +------+ | | | AC | | | +--+---+ | | | +------+ +------+ +--+---+ /-------\ | | | | | | | | | STA | /-/ | WTP +--------------+ GW +----+ Service | | | | | | | | | +------+ +------+ +------+ \-------/ Figure 1 Centralized WLAN Architecture Xue & Sarikaya Expires August 29, 2013 [Page 3] Internet-Draft sta location via DHCP February 2013 However, some issues arise meanwhile if the authentication moved out from the AC. One of the issues is that Gateway can't obtain the WTP information(MAC address, etc) because the WTP management function is located in AC device. The challenge is that WTP information for the subscriber is actually appreciated for operators. For example, subscriber's location information (WTP information ) is required in the charging bill, in order to the collect statistical parameter or push advertisement to special WTP, or locate the fault exactly, etc. This document introduces WTP information transported using DHCPv4/v6. In this procedure, DHCPv4/v6 snooping is deployed on the WTP node or AC node. The DHCPv4/v6 snooping node will recognize the DHCPv4/v6 packets and insert the WTP information into the extension option of DHCPv4/v6 messages . Then the subscriber's WTP information is transported. GW obtains the WTP information through which the subscriber access network. If the WTP information is MAC address, the subscriber location information will be obtained by GW. Also GW can inform location information to AAA server, etc. The operators can use this information to achieve some management, such as locating fault, push advertisement to special WTP, etc. 1.1. Terminology This document uses the following terms. Wireless Termination Point (WTP) The physical or logical network entity that contains an RF antenna and wireless physical layer (PHY) to transmit and receive station traffic for wireless access networks. This definition has the same meaning used in [RFC4118]. It also called AP. Access Controller (AC) The network entity that provides WTP access to the network infrastructure in the data plane, control plane, management plane, or a combination therein, as defined in[RFC4118]. Also the terms used in this document are accordant with the terminologies in [RFC2131]. Gateway (GW) A device in operator access network, who can charge the subscriber authentication. It maybe BRAS (Broadband Remote Access Server) or BNG (Broadband Network Gateway). Xue & Sarikaya Expires August 29, 2013 [Page 4] Internet-Draft sta location via DHCP February 2013 2. Applicability This specification applies when layer 2 network is deployed between WTP and GW or layer 2 network is deployed between WTP and AC. In these cases, the procedure specified in this document should be used for WTP information transmission. It occurs for two scenarios. o AC is deployed as a standalone node, which is WTP management device and doesn't transport the traffic for the subscriber at all, shown in figure 2. o AC is involved in the subscriber traffic transport, shown in figure 3. The subscriber traffic can be transported via Layer 2 network between WTP and AC. Note:the layer 2 connection is assumed between AC and GW. +------+ | | | AC | | | +--+---+ | | | +------+ +------+ Traffic for STA+--+---+ /-------\ | | | +----------------+ | | | | STA | /-/ | WTP +----------------+ GW +----+ Service | | | | | Layer 2 | | | | +------+ +------+ +------+ \-------/ Figure 2 Traffic bypass AC Traffic +------+ +------+ for STA +------+ +------+ /-------\ | | | +-----------+ | | | | | | STA | /-/ | WTP +-----------+ AC +---+ GW +--+ Service | | | | | Layer 2/ | | | | | | +------+ +------+ CAPWAP TUN+------+ +------+ \-------/ Figure 3 Traffic through AC Moreover, this specification applies when DHCPv4/v6 snooping mentioned in [SAVI-DHCP] is deployed on WTP or AC node. Any DHCPv4/v6 protocol agent and server that implements the mechanism described in this document assume that they follow the DHCPv4/v6 general procedure [RFC2131]. Xue & Sarikaya Expires August 29, 2013 [Page 5] Internet-Draft sta location via DHCP February 2013 3. DHCPv4/v6 Operation The DHCPv4/v6 procedure when DHCPv4/v6 snooping is deployed on WTP/AC node is described in this section. Take the first scenario shown as follows for example. The operation for the WTP information transport is shown in figure 4 via DHCPv4 and in figure 5 via DHCPv6 3.1. DHCPv4 Operation +------+ | | | AC | | | +--+---+ +------+ +------+ Traffic for STA+--+---+ +------+ | | | +----------------+ | | | | STA | /-/ | WTP +----------------+ GW | | AAA | | | | | Layer 2 | | | | +------+ +------+ +------+ +------+ | | | | | DHCP snooping | | | | | | | DHCPv4 Discover | | | +---------------->| | | | Insert WTP info | | | into DHCPv4 Message | | | | | | | DHCPv4 Discover(WTP MAC)| | | +--------------------->| | | DHCPv4 offer | | |<----------------+----------------------+ | | DHCPv4 Request | | | +---------------->| | | | Insert|WTP info | | | into DHCPv4 Message | | | | | | | DHCPv4 Request(WTP MAC) | | | +--------------------->| | | | GW obtain WTP info | | DHCPv4 ACK via DHCPv4 option | |<----------------+----------------------+ | | Authentication Procedure | | |<----------------+--------------------->| WTP info | | | | via RADIUS | | | +------------------->| | | | | Xue & Sarikaya Expires August 29, 2013 [Page 6] Internet-Draft sta location via DHCP February 2013 Figure 4 DHCPv4 Operation 1 DHCPv4 snooping is deployed on WTP node. Then WTP node can capture the DHCPv4 message. 2 STA initiates DHCPv4 procedure via DHCPv4 discovery message. 3 WTP recognizes the DHCPv4 packets and inserts the WTP information,such as MAC address into the new DHCPv4 option of DHCPv4 message, both DHCPv4 Discovery and DHCPv4 Request . 4 The WTP information for the subscriber can be obtained by GW via DHCPv4 option. GW treats this information as subscriber profile. 5 After IP address assignment, the authentication procedure is initiated. During the authentication procedure, WTP info can be transported to AAA service via RADIUS message. The operators can use this information to achieve some management, such as locating fault, push advertisement to special WTP, etc. This step is out the scope of this specification. As the other scenario shown in figure 3, AC is responsible to transport subscriber traffic from AP to GW. Because AC manages and configures WTP, it is assumed that AC has record the WTP MAC address. So here, the DHCPv4 snooping function is deployed on AC node, and the procedure is same as shown in figure 6. 3.2. DHCPv6 Operation Xue & Sarikaya Expires August 29, 2013 [Page 7] Internet-Draft sta location via DHCP February 2013 +------+ | | | AC | | | +--+---+ +------+ +------+ Traffic for STA+--+---+ +------+ | | | +----------------+ | | | | STA | /-/ | WTP +----------------+ GW | | AAA | | | | | Layer 2 | | | | +------+ +------+ +------+ +------+ | | | | | DHCP snooping | | | | | | | DHCPv6 Solicit | | | +---------------->| | | | Insert WTP info | | | into DHCPv6 Message | | | | | | | DHCPv6 Solicit (WTP MAC)| | | +--------------------->| | | DHCPv6 Advertise | | |<----------------+----------------------+ | | DHCPv6 Request | | | +---------------->| | | | Insert|WTP info | | | into DHCPv6 Message | | | | | | | DHCPv6 Request(WTP MAC) | | | +--------------------->| | | | GW obtain WTP info | | DHCPv6 Reply via DHCPv6 option | |<----------------+----------------------+ | | Authentication Procedure | | |<----------------+--------------------->| WTP info | | | | via RADIUS | | | +------------------->| | | | | Figure 5 DHCPv6 Operation The procedure of DHCPv6 is similar as DHCPv4. The detailed description is ignored. 4. Location Information Option This documents defines a new option called Location Information Xue & Sarikaya Expires August 29, 2013 [Page 8] Internet-Draft sta location via DHCP February 2013 Option. It is an optional option for the specific subscriber's WTP information transport. The format of the DHCPv4 Location Information Option is: 0 1 2 3 4 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 | WTP information | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | WTP information (cont) | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 6 Location Information Option for DHCPv4 The code is recommended to the value still unassigned. In this document, value 140 is suggested. The length is 6, while the WTP information field is just filled with WTP MAC address. The format of the DHCPv6 location information option for DHCPv6 is shown as follows. The location information option follows the common base format defined in [RFC3315]. 0 1 2 3 4 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 | option-len | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | WTP information | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 7 Locaiton information Option for DHCPv6 The option-code is recommended an unsigned integer to identify location information option for DHCPv6. Value 35 is suggested. The length is 6, while the WTP information field is just filled with WTP MAC address. However, the WTP information will be extended in next version if more requirement can be clarified. 5. IANA Considerations TBD Xue & Sarikaya Expires August 29, 2013 [Page 9] Internet-Draft sta location via DHCP February 2013 6. Security Considerations TBD 7. References 7.1. 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. [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. [RFC3369] Housley, R., "Cryptographic Message Syntax (CMS)", RFC 3369, August 2002. [RFC4118] Yang, L., Zerfos, P., and E. Sadot, "Architecture Taxonomy for Control and Provisioning of Wireless Access Points (CAPWAP)", RFC 4118, June 2005. 7.2. Informative References [SAVI-DHCP] "draft-ietf-savi-dhcp", June 2012. Authors' Addresses Li Xue Huawei No.156 Beiqing Rd. Z-park, Shi-Chuang-Ke-Ji-Shi-Fan-Yuan, Beijing, HaiDian District 100095 China Email: xueli@huawei.com Xue & Sarikaya Expires August 29, 2013 [Page 10] Internet-Draft sta location via DHCP February 2013 Behcet Sarikaya Huawei 5340 Legacy Dr. Plano, TX 75024 Email: sarikaya@ieee.org Xue & Sarikaya Expires August 29, 2013 [Page 11]