Network Working Group L. Xue Internet-Draft Huawei Intended status: Informational February 18, 2013 Expires: August 22, 2013 DHCP option for STA Location Information draft-xue-dhc-location-option-00 Abstract This document introduces WTP information transported using DHCP. In this procedure, DHCP snooping is deployed on the WTP node or AC node. Then the WTP information can be inserted into the extension option of DHCP 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 22, 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 Expires August 22, 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. DHCP Operation . . . . . . . . . . . . . . . . . . . . . . . . 6 4. Location Information Option . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 8 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References . . . . . . . . . . . . . . . . . . . 8 7.2. Informative References . . . . . . . . . . . . . . . . . . 8 Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 8 Xue Expires August 22, 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 Expires August 22, 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 DHCP. In this procedure, DHCP snooping is deployed on the WTP node or AC node. The DHCP snooping node will recognize the DHCP packets and insert the WTP information into the extension option of DHCP 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 Expires August 22, 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 or CAPWAP tunnel 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 DHCP snooping mentioned in [SAVI-DHCP] is deployed on WTP or AC node. Any DHCP protocol agent and server that implements the mechanism described in this document assume that they follow the DHCP general procedure [RFC2131]. Xue Expires August 22, 2013 [Page 5] Internet-Draft sta location via DHCP February 2013 3. DHCP Operation The DHCP procedure when DHCP snooping is deployed on WTP/AC node is described in this section. Take the first scenario shown in figure 2 for example. The operation for the WTP information transport is shown in figure 4. +------+ | | | AC | | | +--+---+ +------+ +------+ Traffic for STA+--+---+ +------+ | | | +----------------+ | | | | STA | /-/ | WTP +----------------+ GW | | AAA | | | | | Layer 2 | | | | +------+ +------+ +------+ +------+ | | | | | 1 DHCP snooping | | | | | | | 2 DHCP Discover | | | +---------------->| | | | 3a Insert WTP info | | | into DHCP message | | | | | | | |DHCP Discover(WTP MAC)| | | +--------------------->| | | DHCP offer | | |<----------------+----------------------+ | | DHCP Request | | | +---------------->| | | | 3b Insert|WTP info | | | into DHCP message | | | | | | | |DHCP Request(WTP MAC) | | | +--------------------->| | | | 4 GW obtain WTP info | | DHCP ACK via DHCP option | |<----------------+----------------------+ | | Authentication Procedure | | |<----------------+--------------------->| 5 WTP info | | | | via RADIUS | | | +------------------->| | | | | Figure 4 DHCP Operation 1 DHCP snooping is deployed on WTP node. Then WTP node can capture Xue Expires August 22, 2013 [Page 6] Internet-Draft sta location via DHCP February 2013 the DHCP message. 2 STA initiates DHCP procedure via DHCP discovery message. 3 WTP recognizes the DHCP packets and inserts the WTP information,such as MAC address into the new DHCP option of DHCP message, both DHCP Discovery and DHCP Request . 4 The WTP information for the subscriber can be obtained by GW via DHCP 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 DHCP snooping function is deployed on AC node, and the procedure is same as shown in figure 4. 4. Location Information Option This documents defines a new option called Location Information Option. It is an optional option for the specific subscriber's WTP information transport. The format of the 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 5 Location Information Option 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 in WTP MAC address. Xue Expires August 22, 2013 [Page 7] Internet-Draft sta location via DHCP February 2013 5. IANA Considerations TBD 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. [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. Author's Address 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 Expires August 22, 2013 [Page 8]