Internet Draft H. Cheng S. Govindan Document: Functionality Classifications for Panasonic Singapore Labs Control and Provisioning of Wireless Access Points Expires: August 2004 February 2004 Functionality Classifications for Control and Provisioning of Wireless Access Points (CAPWAP) draft-cheng-capwap-classifications-00.txt Status of this Memo This document is an Internet-Draft and is in full conformance with all provisions of Section 10 of RFC2026 [1]. Internet-Drafts are working documents of the Internet Engineering Task Force (IETF), its areas, and its working groups. Note that other groups may also distribute working documents as Internet- Drafts. 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." The list of current Internet-Drafts can be accessed at http://www.ietf.org/ietf/1id-abstracts.txt The list of Internet-Draft Shadow Directories can be accessed at http://www.ietf.org/shadow.html. Abstract This document presents a means for classifying wireless local area network (WLAN) functionality for the Control and Provisioning of Wireless Access Points framework. It also puts forth the advantages of using consistent classifications in dividing functionality between the Access Controllers and Access Points that make up a WLAN. Conventions used in this document 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 [2]. H. Cheng Expires - August 2004 [Page 1] Internet-Draft Functionality Classifications February 2004 Table of Contents 1. Introduction...................................................3 2. WLAN Functionality Classifications.............................4 3. Need for Classifications.......................................5 4. Conclusion.....................................................6 Security Considerations...........................................7 References........................................................7 Author's Addresses................................................7 Intellectual Property.............................................7 Full Copyright Statement..........................................8 H. Cheng Expires - August 2004 [Page 2] Internet-Draft Functionality Classifications February 2004 1. Introduction Wireless local area networks (WLANs) have generated tremendous interests among both consumers and the industry. Consequently, developments in this field are fast-paced and are taken up by a number of participants. As with any process that involves diversified participation, developments in WLAN technologies have led to the introduction of different types of devices, architectures and strategies. Although these advancements are based on the standardized IEEE 802.11 specifications, they nonetheless present a host of incompatibility issues that ultimately affect the end market. A particular example of such incompatibility is related to WLAN architectures that incorporate centralized controller entities or Access Controllers (ACs). ACs were introduced to simplify the deployment and management of large-scale WLANs by aggregating control of a number of Access Points (APs) at a single controller entity. Additionally, designs for these entities include consolidating some WLAN functionality at the ACs and leaving the remaining to the APs. While such division of functionality among APs and ACs is widely endorsed, the specifics in which they are accomplished vary among manufacturers and their implementations. These differences introduce complications for consumers and enterprises, which in turn adversely affects WLAN adoption. This document presents a means for classifying WLAN functions based on operational similarities. The functionality may then be divided between ACs and APs on the basis of the classifications. H. Cheng Expires - August 2004 [Page 3] Internet-Draft Functionality Classifications February 2004 2. WLAN Functionality Classifications Table 1 illustrates means for classifying WLAN functionality. --------------------------------------------------------------------- | Type | Type | Constituent | Justifications | | | Description | Functions | | --------------------------------------------------------------------- | 1 | Radio | Transmission/ | Functionality common| | | Frequency (RF) | Reception, | to the RF interface | | | | Coding, | are to be placed | | | | Modulation, | together. This makes| | | | Power control, | for easier design | | | | Wireless interface | and operation. | | | | monitoring, | | | | | Beacon control | | | | | | | | 2 | L2 Processing | Authentication, | Functionality common| | | | Association, | to the MAC layer are| | | | Encryption/ | to be classified | | | | Decryption, | together so that L2 | | | | Bridging | PDUs are processed | | | | | in one unit. This | | | | | follows from the | | | | | established ISO-OSI | | | | | layering. | | | | | | | 3 | L3 Processing | QoS processing, | Functionality common| | | | Routing, | to the IP layer are | | | | IP processing | to be classified | | | | | together so that | | | | | processing of L3 | | | | | PDUs may be | | | | | consolidated in one | | | | | functional unit. | | | | | | | 4 | Control | Policy management, | General control is | | | | Parameter settings, | common to all APs. | | | | Configuration, | As such, these are | | | | QoS management | to be aggregated. | | | | Access control | | --------------------------------------------------------------------- Table 1 H. Cheng Expires - August 2004 [Page 4] Internet-Draft Functionality Classifications February 2004 The functionality types are classified based on their relations to the ISO-OSI protocol layers. Functionality type 1, Radio Frequency (RF), relates to those functional aspects that are common to the RF interface between an AP and a mobile client. This is the physical layer. Next, L2 processing relates to the subsequent MAC layer while type 3 L3 processing deals with the network layer. Finally, type 4 functionality combines control aspects that are common to all APs. The advantage of such classifications is that it is based on well established concepts of protocol layering. This ensures that the execution of different types of functionality may be optimized in independent and efficient ways. And with the expected growth in WLAN load levels, optimal performance of network entities becomes a significant priority. It is quite obvious from the table that the Type 2 functions corresponds to the MAC layer functions defined by the IEEE802.11. Therefore, it would be possible that the functions to be split in further detail. For example, the security part, e.g. 802.11i, and the QoS control part, e.g. 802.11e, could be separate as Type 2A, Type 2B etc. But this kind of split of the IEEE802.11 MAC function needs to be rectified by the IEEE. The general principle is that the split functions could operate separately. 3. Need for Classifications The classifications of WLAN functionality represent the integral units that may be implemented in ACs and APs as parts of their WLAN service capabilities. As such, enterprises may choose for example, APs comprising types 1, 2 and 4 functionalities and a corresponding controller capable of type 3 IP processing. Alternatively, APs may be simplified to realize only type 1 RF functionality while a sophisticated AC realizes the other remaining types of functionalities. This follows from the prevailing trend where ACs aggregate some WLAN functionality leaving only the remaining for the APs, albeit in a structured manner. As such, standardized means of classifications allow for consistency in addressing various types of WLAN devices and divisions. This leads to increased flexibility in designs for ACs and APs. Such flexibility in turn ensures that different market requirements are addressed in efficient and focused ways. So in addition to providing various options for dividing functionality, the classifications also promote interoperability between different types of devices. The classifications also form a based for identifying different types of APs, ACs and their compatibilities. For example, APs incorporating H. Cheng Expires - August 2004 [Page 5] Internet-Draft Functionality Classifications February 2004 functionality types 1 and 2 would require support from a corresponding types 3 and 4 AC or from a set of ACs of types 3 and 4. In essence, the classifications present opportunities for certification processes between APs and ACs. 4. Conclusion The classifications for WLAN functionalities presented so far need to be realized as part of the CAPWAP effort. Doing so would allow for ease and flexibility in WLAN deployments. Also, establishing a consistent means of classifications would ensure interoperability between different types of APs and ACs from different manufacturers. Additionally, it presents opportunities to optimize network entities so as to deliver performance commensurate with WLAN needs and expectations. There is also a need for devising appropriate policies for dividing functionality among ACs and APs which would further simplify the deployment of WLANs comprising different types of devices with varying types of functionality. These aspects would give manufacturers greater flexibility in designing their products knowing that they would be compatible with devices from other manufacturers. Similarly, consumers gain with the flexibility in choosing and deploying equipment suited to their particular needs. H. Cheng Expires - August 2004 [Page 6] Internet-Draft Functionality Classifications February 2004 Security Considerations Security is an integral issue to CAPWAP. As such, the aspects put forth in this document will base their security requirements on that of the broader CAPWAP goals. References 1 "The Internet Standards Process -- Revision 3", BCP 9, October 1996, 2 "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, March 1997, Author's Addresses Hong Cheng Panasonic Singapore Laboratories Pte Ltd Blk 1022 Tai Seng Ave #06-3530 Tai Seng Industrial Estate Singapore 534415 Phone: (+65) 6554 5477 Email: hcheng@psl.com.sg Saravanan Govindan Panasonic Singapore Laboratories Pte Ltd Blk 1022 Tai Seng Ave #06-3530 Tai Seng Industrial Estate Singapore 534415 Phone: (+65) 6554 5441 Email: sgovindan@psl.com.sg Intellectual Property The IETF takes no position regarding the validity or scope of any intellectual property or other rights that might be claimed to pertain to the implementation or use of the technology described in H. 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