Network Working Group L. Xue Internet-Draft Huawei Intended status: Informational B. Sarikaya Expires: August 22, 2013 Huawei USA February 18, 2013 DHCPv4 and DHCPv6 options for Access Point Location Information draft-xue-dhcp-location-option-00 Abstract This document introduces Control and Provisioning of Wireless Access Points Wireless Termination Point information transported using DHCP. In this procedure, DHCP snooping is deployed on the Wireless Termination Point node or Access Controller node. Then the Wireless Termination Point information can be inserted into the DHCP message in extension option. Because the DHCP messages is send out from the subscriber, so binding between Wireless Termination Point information and subscriber is set up after this procedure. Then Gateway obtains the Wireless Termination Point information through the subscriber access 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 Xue & Sarikaya Expires August 22, 2013 [Page 1] Internet-Draft AP location via DHCP February 2013 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 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 . . . . . . . . . . . . . . . . . . . . . . . . . 4 3. DHCP Operation . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Location Information Option . . . . . . . . . . . . . . . . . . 7 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7 6. Security Considerations . . . . . . . . . . . . . . . . . . . . 8 7. References . . . . . . . . . . . . . . . . . . . . . . . . . . 8 7.1. Normative References . . . . . . . . . . . . . . . . . . . 8 7.2. Informative References . . . . . . . . . . . . . . . . . . 8 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 8 Xue & Sarikaya Expires August 22, 2013 [Page 2] Internet-Draft AP 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 WLAN is used to supplement cellular (2G/3G/LTE) network. It provides a good chance for operators to provide broadband service with less CAPEX. Traditionally, the 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 in this point. There are two types to WTP in exiting network, defined as standalone WTP and controlled WTP. The standalone WTP refers to the WTP in autonomous WLAN architecture. WTP is responsible for all WLAN functionality, such as encryption/decryption, authentication, etc. Instead, controlled WTP refers to the WTP in centralized WLAN architecture. In that case, WTP management and subscriber authentication is implemented on AC device. It is possible that AC in the existing network 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 deployment the software and hardware upgrade risks for carriers. So it is a popular scenario to split the authentication function from AC to Service Gateway, 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 22, 2013 [Page 3] Internet-Draft AP location via DHCP February 2013 However, if the authentication moved out from the AC, some issues arise meanwhile. One of the issues is that Service 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 appreciated for operators in the charge bill, in order to the collect statistical parameter and push advertisement to special WTP, or locate the fault locating exactly, etc. 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 DHCP message in extension option. Because the DHCP messages is send out from the subscriber, so binding between WTP information and subscriber is set up after this procedure. Then GW obtain the WTP information through which the subscriber access network. 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]. 2. Applicability This specification applies when layer 2 network is deployed between WTP and GW, where DHCP relay function isn't deployed on the access device. In these cases, the procedure specified here should be used for WTP information transmission. This can occur for two scenarios. First, the AC is deployed as a standalone node, which doesn't transport the traffic for the subscriber at all, shown in figure 2. Other, the AC deployed on the path between WTP and GW, is involved in the subscriber traffic transport, shown in figure 3. In the second Xue & Sarikaya Expires August 22, 2013 [Page 4] Internet-Draft AP location via DHCP February 2013 case, the layer 2 connection is assumed between AC and GW as noted. +------+ | | | 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, the specification applies when DHCP snooping mentioned in [I-D.ietf-savi-dhcp] must be deployed on WTP or AC node. Any DHCP protocol agent and server that implements the mechanisms described in this document can assume that they follow the DHCP general procedure must follow [RFC2131]. 3. DHCP Operation The DHCP procedure when DHCP snooping is deployed on WTP/AC node is described in this section. Take the scenario as subscriber traffic bypass AC (figure 3) for example. The operation for the WTP information transport is shown in figure 4. Xue & Sarikaya Expires August 22, 2013 [Page 5] Internet-Draft AP location via DHCP February 2013 +------+ | | | 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 the DHCP message. 2 STA initiates DHCP procedure via DHCP discovery message. 3 WTP can insert the WTP information,such as MAC address into the new DHCP option of DHCP message, both DHCP Discovery and DHCP Request . Xue & Sarikaya Expires August 22, 2013 [Page 6] Internet-Draft AP location via DHCP February 2013 4 The WTP information for the subscriber can be obtained by GW via DHCP option. The 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. Then the subscriber bill can be created contain the access WTP information. This step is out the scope of this specification. As the other scenario shown in figure 3, the AC is deployed on the path between WTP and GW. Additionally, AC is responsible to transport subscriber traffic from AP to GW. In this case, AC manages and configures WTP. We assume AC has record the WTP MAC address. So here, the DHCP snooping function is deployed on AC node in this scenario. However, 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: code length WTP information field +-------+-------+-----------------------------------------------+ | | | | | | | | | | | | +-------+-------+-----------------------------------------------+ 8 16 n 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. 5. IANA Considerations TBD Xue & Sarikaya Expires August 22, 2013 [Page 7] Internet-Draft AP 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. [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 [I-D.ietf-savi-dhcp] Bi, J., Wu, J., Yao, G., and F. Baker, "SAVI Solution for DHCP", draft-ietf-savi-dhcp-15 (work in progress), September 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 22, 2013 [Page 8] Internet-Draft AP location via DHCP February 2013 Behcet Sarikaya Huawei USA 5340 Legacy Dr. Plano, TX 75024 Email: sarikaya@ieee.org Xue & Sarikaya Expires August 22, 2013 [Page 9]