6lo B. Sarikaya, Ed. Internet-Draft Huawei USA Intended status: Standards Track P. Thubert, Ed. Expires: April 21, 2016 Cisco October 19, 2015 Address Protected Neighbor Discovery for Low-power and Lossy Networks draft-sarikaya-6lo-ap-nd-01 Abstract This document defines an extension of 6LoWPAN Neighbor Discovery for application in low-power and lossy networks. The protocol is specified to be protected and to support multi-hop operation. A node computes its Cryptographic, Unique Interface ID, and associates one or more of its Registered Addresses with that Cryptographic ID in place of the EUI-64 that is used in RFC 6775 to uniquely identify the interface of the Registered Address. Once an address is registered with a Cryptographic ID, only the owner of that ID can modify the state in the 6LR and 6LBR regarding the Registered Address. 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 April 21, 2016. Copyright Notice Copyright (c) 2015 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 Sarikaya & Thubert Expires April 21, 2016 [Page 1] Internet-Draft Address Protection ND for LLN October 2015 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 . . . . . . . . . . . . . . . . . . . . . . . . 2 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 3 3. Requirements . . . . . . . . . . . . . . . . . . . . . . . . 4 4. Protocol Interactions . . . . . . . . . . . . . . . . . . . . 4 4.1. Overview . . . . . . . . . . . . . . . . . . . . . . . . 4 4.2. Protocol Operations . . . . . . . . . . . . . . . . . . . 7 4.2.1. Calculation of Cryptographic Identifier . . . . . . . 8 4.3. Multihop Operation . . . . . . . . . . . . . . . . . . . 10 5. Security Considerations . . . . . . . . . . . . . . . . . . . 11 6. IANA considerations . . . . . . . . . . . . . . . . . . . . . 12 7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12 8. References . . . . . . . . . . . . . . . . . . . . . . . . . 12 8.1. Normative References . . . . . . . . . . . . . . . . . . 12 8.2. Informative references . . . . . . . . . . . . . . . . . 13 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14 1. Introduction Neighbor discovery for IPv6 [RFC4861] and stateless address autoconfiguration [RFC4862], together referred to as neighbor discovery protocols (NDP), are defined for regular hosts operating with wired/wireless links. These protocols are not suitable and require optimizations for resource constrained, low power hosts operating with LLN for low-power and lossy networks. Neighbor Discovery optimizations for 6LoWPAN networks include simple optimizations such as a host address registration feature using the address registration option (ARO) which is sent in unicast Neighbor Solicitation (NS) and Neighbor Advertisement (NA) messages [RFC6775]. With 6LoWPAN ND [RFC6775], the ARO option includes a EUI-64 address to uniquely identify the interface of the Registered Address on the registering device, so as to correlate further registrations for the same address and avoid address duplication. The EUI-64 address is not secured and its ownership cannot be verified. It results that any device claiming the same EUI-64 address may take over a registration and attract the traffic for that address. In this document, we extend 6LoWPAN ND to protect the address ownership with cryptographic material, but as opposed to Secure Neighbor Discovery (SEND) [RFC3971], [RFC3972], the cryptographic material is not embedded in the Interface ID (IID) in an IPv6 address Sarikaya & Thubert Expires April 21, 2016 [Page 2] Internet-Draft Address Protection ND for LLN October 2015 but used as a correlator associated to the registration of the IPv6 address. This approach is made possible with 6LoWPAN ND [RFC6775], where the 6LR and the 6LBR maintain a state for each Registered Address. If a cryptographic ID is associated with an original 6LoWPAN ND registration and stored in the registration state, then it can be used to validate that any update to the registration state is made by the owner of that ID. To achieve this, this specification replaces the EUI-64 address, that is used in 6LoWPAN ND to avoid address duplication, with cryptographic material whose ownership can be verified; it also provides new means for the 6LR to validate ownership of the registration thus that of the registered address by the registering device. The resulting protocol is called Protected address autoconfiguration and registration protocol (ND-PAAR). A node generates one 64-bit cryptographic ID and uses it as Unique Interface ID in the registration of (one or more of) its addresses with the 6LR, which it attaches to and uses as default router. The 6LR validates ownership of the cryptographic ID typically upon creation or update of a registration state, for instance following an apparent movement from a point of attachment to another. The ARO option is modified to carry the Unique Interface ID, and through the DAR/DAC exchange, the 6LBR is kept aware that this is the case, i.e. unique and whether the 6LR has verified the claim. 2. 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 [RFC2119]. Readers are expected to be familiar with all the terms and concepts that are discussed in [RFC3971], [RFC3972], "neighbor Discovery for IP version 6" [RFC4861], "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): Overview, Assumptions, Problem Statement, and Goals" [RFC4919], neighbor Discovery Optimization for Low-power and Lossy Networks [RFC6775] where the 6LoWPAN Router (6LR) and the 6LoWPAN Border Router (6LBR) are introduced, and [I-D.chakrabarti-nordmark-6man-efficient-nd], which proposes an evolution of [RFC6775] for a larger applicability. The document also conforms to the terms and models described in [RFC5889] and uses the vocabulary and the concepts defined in [RFC4291] for the IPv6 Architecture. This document uses [RFC7102] for Terminology in Low power And Lossy Networks. Sarikaya & Thubert Expires April 21, 2016 [Page 3] Internet-Draft Address Protection ND for LLN October 2015 3. Requirements In this section we state requirements of a secure neighbor discovery protocol for low-power and lossy networks. The protocol MUST be based on the Neighbor Discovery Optimization for Low-power and Lossy Networks protocol defined in [RFC6775] due to the host-initiated interactions to allow for sleeping hosts, elimination of multicast-based address resolution for hosts, etc. New options to be added to Neighbor Solicitation messages MUST lead to small packet sizes. Smaller packet sizes facilitate low-power transmission by resource constrained nodes on lossy links. The support of the registration mechanism SHOULD be extended to more LLN links than IEEE 802.15.4, matching at least the LLN links for which a 6lo "IPv6 over foo" specification exists, as well as Low- Power Wi-Fi. As part of this extension, a mechanism to compute a unique Identifier should be provided, with the capability to form a Link Local Address that SHOULD be unique at least within the LLN connected to a 6LBR discovered by ND in each node within the LLN. The Address Registration Option used in the ND registration SHOULD be extended to carry the relevant forms of Unique Interface IDentifier. The Neighbour Discovery should specify the formation of a site-local address that follows the security recommendations from [RFC7217]. 4. Protocol Interactions Protected address autoconfiguration and registration neighbor discovery protocol (ND-PAAR) modifies Neighbor Discovery Optimization for Low-power and Lossy Networks [RFC6775] as explained in this section. 4.1. Overview The scope of the present work is a 6LoWPAN Low Power Lossy Network (LLN), typically a stub network connected to a larger IP network via a Border Router called a 6LBR per [RFC6775]. Sarikaya & Thubert Expires April 21, 2016 [Page 4] Internet-Draft Address Protection ND for LLN October 2015 ---+-------- ............ ------------ | External Network | | +-----+ | | LLN Border | | router +-----+ o o o o o o o o o LLN o o o o o o o o Figure 1: Basic Configuration The 6LBR maintains a registration state for all devices in the attached LLN, and, in conjunction with the first-hop router (the 6LR), is in position to validate uniqueness and grant ownership of an IPv6 address before it can be used in the LLN. This is a fundamental difference with a classical network that relies on IPv6 address auto- configuration [RFC4862], where there is no guarantee of ownership from the network, and any IPv6 Neighbor Discovery packet must be individually secured [RFC3971]. In a route-over mesh network, the 6LR is directly connected to the host device; this specification expects that peer-wise Layer-2 security is deployed so that all the packets from a particular host are identified as such by the 6LR. The 6LR may be multiple hops away from the 6LBR. Packets are routed between the 6LR and the 6LBR via other 6LRs; this specification expects that a chain of trust is established so that a packet that was validated by the first 6LR can be safely routed by the next 6LRs and 6LBR. The [I-D.ietf-6tisch-architecture] suggests to use RPL [RFC6550] as the routing protocol between the 6LRs and the 6LBR, and to leverage [I-D.chakrabarti-nordmark-6man-efficient-nd] to extend the LLN in a larger multilink subnet [RFC4903]. In that model, a registration flow happens as shown in Figure 2: Sarikaya & Thubert Expires April 21, 2016 [Page 5] Internet-Draft Address Protection ND for LLN October 2015 6LoWPAN Node 6LR 6LBR 6BBR (RPL leaf) (router) (root) | | | | | 6LoWPAN ND |6LoWPAN ND+RPL | Efficient ND | IPv6 ND | LLN link |Route-Over mesh| IPv6 link | Backbone | | | | | NS(ARO) | | | |-------------->| | | | 6LoWPAN ND | DAR (then DAO)| | | |-------------->| | | | | NS(ARO) | | | |-------------->| | | | | DAD | | | |------> | | | | | | | NA(ARO) | | | |<--------------| | | DAC | | | |<--------------| | | NA(ARO) | | | |<--------------| | | Figure 2: (Re-)Registration Flow over Multi-Link Subnet A new device that joins the network auto-configures an address and performs an initial registration to an on-link 6LR with an NS message that carries a new Address Registration Option (ARO) [RFC6775]. The 6LR validates the address with the central 6LBR using a DAR/DAC exchange, and the 6LR confirms (or infirms) the address ownership with an NA message that also carries an Address Registration Option. The registration mechanism in [RFC6775] was created for the original purpose of Duplicate Address Detection (DAD), whereby use of an address would be granted as long as the address is not already present in the subnet. But [RFC6775] does not require that the 6LR use the registration for source address validation (SAVI). In order to validate address ownership, that mechanism enables the 6LBR to correlate further claims for a registered address with the device to which it is granted, based on a Unique Interface IDentifier (UID) that is derived from the MAC address of the device (EUI-64). The limitation of the mechanism in [RFC6775] is that it does not enable to prove the UID itself, so any node connected to the subnet and aware of the address/UID mapping may effectively fake the same UID and steal an address. Sarikaya & Thubert Expires April 21, 2016 [Page 6] Internet-Draft Address Protection ND for LLN October 2015 This draft uses a randomly generated value as an alternate UID for the registration. Proof of ownership of the UID is passed with the first registration to a given 6LR, and enforced at the 6LR, which validates the proof. With this new operation, the 6LR allows only packets from a connected host if the connected host owns the registration of the source address of the packet. If a chain of trust is present between the 6LR and the 6LBR, then there is no need to propagate the proof of ownership to the 6LBR. All the 6LBR need to know is that this particular UID is randomly generated, so as to enforce that any update via a different 6LR is also random. 4.2. Protocol Operations Protocol interactions are as defined in Figure 2. The crypto ID is calculated as described in Section 4.2.1. The Target Address field in NS message is set to the prefix concatenated with the node's address. This address does not need duplicate address detection as crypto ID is globally unique. So a host cannot steal an address that is already registered unless it has the key for the crypto ID. The same crypto ID can thus be used to protect multiple addresses e.g. when the node receives a different prefix. Local or on-link protocol interactions are given in Figure 3. Crypto ID and ARO are passed to and stored by the 6LR/6LBR on the first NS and not sent again the in the next NS. The 6LR/6LBR ensures first-come/first-serve by storing the ARO and the crypto ID correlated to the target being registered. Then, if the node is the first to claim any address it likes, then it becomes owner of that address and the address is bound to the crypto ID in the 6LR/6LBR registry. This procedure avoids the constrained device to compute multiple keys for multiple addresses. The registration process allows the node to tie all the addresses to the same crypto ID and have the 6LR/6LBR enforce first come first serve after that. Sarikaya & Thubert Expires April 21, 2016 [Page 7] Internet-Draft Address Protection ND for LLN October 2015 6LN 6LR | | |<-----------------------RA-------------------------------| | | |---------------NS with ARO and Random UID --------------->| | | |<-----------------------NA with ARO (status=req-proof) --| | | |---------------NS with ARO and Random UID->| | | |<-----------------------NA with ARO----------------------| | | ... | | |---------------NS with ARO and Random UID --------------->| | | | |<-----------------------NA with ARO----------------------| ... | | |---------------NS with ARO and Random UID --------------->| | | | |<-----------------------NA with ARO----------------------| Figure 3: On-link Protocol Operation 4.2.1. Calculation of Cryptographic Identifier Elliptic Curve Cryptography (ECC) is used in the calculation of cryptographical identifier. The digital signature is constructed by using the 6LN's private key over its EUI-64, i.e. its MAC address. The signature value is computed using the ECDSA signature algorithm and hash function used is SHA-256. Public Key is the most important parameter in CGA Parameters (sent by 6LN in an NS message). ECC Public Key could be in uncompressed form or in compressed form where the first octet of the OCTET STRING is 0x04 and 0x02 or 0x03, respectively. Point compression using secp256r1 reduces the key size by 32 octets. After the calculation, 6LN sends it along with the CGA parameters in the first NS message, see Figure 3. In order to send Cryptographical Identifier a neighbor discovery option is defined in Figure 4. As defined in the figure this ID is variable length, varying between 64 to 128 bits. This ID is 128 bits long if it is used as IPv6 address. 6LN also sends some other parameters to enable 6LR or 6LBR to verify the crypto ID. One of them is 6LN's MAC address which is sent in Address Registration Option (ARO) as defined in [RFC6775]. The next Sarikaya & Thubert Expires April 21, 2016 [Page 8] Internet-Draft Address Protection ND for LLN October 2015 one is shown in Figure 5. In that figure, CGA Parameters field contains the public key, prefix and some other values. Digital signature option contains the signature of the CGA calculated using 6LN's private key. 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Status | Reserved | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Reserved | Registration Lifetime | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | + crypto ID + | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 4: Crypto ID Option Type: TBA Length: 8-bit unsigned integer. The length of the option in units of 8 bytes. It is 2 or 3, if crypto ID is 128 bits. Status: 8-bit unsigned integer. Indicates the status of a registration in the NA response. MUST be set to 0 in NS messages. See below. Reserved: This field is unused. It MUST be initialized to zero by the sender and MUST be ignored by the receiver. Registration Lifetime: 16-bit unsigned integer. The amount of time in units of 60 seconds that the router should retain the NCE for the sender of the NS that includes this option. Crypto ID Variable length field to carry the cryptographical identifier or random UID. This field is normally 64 bits long. It could be 128 bits long if IPv6 address is used as the crypto ID. Sarikaya & Thubert Expires April 21, 2016 [Page 9] Internet-Draft Address Protection ND for LLN October 2015 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 +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | Type | Length | Pad Length | Sig. Length | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . CGA Parameters . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Digital Signature . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ | | . . . Padding . . . | | +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ Figure 5: CGA Parameters Option Type TBA Length The length of the option in units of 8 octets. Pad Length The length of the Padding field. Sig Length The length of the Digital Signature field. CGA Parameters The CGA Parameters field is variable-length containing the CGA Parameters data structure. Digital Signature The Digital Signature field is a variable length field containing a Elliptic Curve Digital Signature Algorithm (ECDSA) signature (with SHA-256 and P-256 curve of [FIPS-186-3]). 4.3. Multihop Operation In multihop 6LoWPAN, 6LBR sends RAs with prefixes downstream and it is the 6LR that receives and relays them to the nodes. 6LR and 6LBR communicate with the ICMPv6 Duplicate Address Request (DAR) and the Duplicate Address Confirmation (DAC) messages. The DAR and DAC use Sarikaya & Thubert Expires April 21, 2016 [Page 10] Internet-Draft Address Protection ND for LLN October 2015 the same message format as NS and NA with different ICMPv6 type values. In ND-PAAR we extend DAR/DAC messages to carry cryptographically generated UID. In a multihop 6LoWPAN, the node exchanges the messages shown in Figure 2. The 6LBR must be aware of who owns an address (EUI-64) to defend the first user if there is an attacker on another 6LR. Because of this the content that the source signs and the signature needs to be propagated to the 6LBR in DAR message. For this purpose we need the DAR message sent by 6LR to 6LBR MUST contain CGA Parameters and Digital Signature Option carrying the CGA that the node calculates and its public key. DAR message also contains ARO. It is possible that occasionally, 6LR may miss the node's UID (that it received in ARO). 6LR should be able to ask for it again. This is done by restarting the exchanges shown in Figure 3. The result enables 6LR to refresh the information that was lost. 6LR MUST send DAR message with ARO to 6LBR. 6LBR as a reply forms a DAC message with the information copied from the DAR and the Status field is set to zero. With this exchange, the 6LBR can (re)validate and store the information to make sure that the 6LR is not a fake. 5. Security Considerations The same considerations regarding the threats to the Local Link Not Covered (as in [RFC3971]) apply. The threats discussed in Section 9.2 of [RFC3971] are countered by the protocol described in this document as well. As to the attacks to the protocol itself, denial of service attacks that involve producing a very high number of packets are deemed unlikely because of the assumptions on the node capabilities in low- power and lossy networks. A collision of ID in ND-PAAR is a really rare event that does not prevent the protocol operation though it opens a window for a node to hijack an address from another. The nodes would normally not be aware that they are in this situation, and the only thing they could do if they knew would be to steal addresses from one another, so the damage is limited to these 2 nodes. Sarikaya & Thubert Expires April 21, 2016 [Page 11] Internet-Draft Address Protection ND for LLN October 2015 6. IANA considerations TBD. 7. Acknowledgements TBD. 8. References 8.1. Normative References [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate Requirement Levels", BCP 14, RFC 2119, DOI 10.17487/RFC2119, March 1997, . [RFC3756] Nikander, P., Ed., Kempf, J., and E. Nordmark, "IPv6 Neighbor Discovery (ND) Trust Models and Threats", RFC 3756, DOI 10.17487/RFC3756, May 2004, . [RFC3971] Arkko, J., Ed., Kempf, J., Zill, B., and P. Nikander, "SEcure Neighbor Discovery (SEND)", RFC 3971, DOI 10.17487/RFC3971, March 2005, . [RFC3972] Aura, T., "Cryptographically Generated Addresses (CGA)", RFC 3972, DOI 10.17487/RFC3972, March 2005, . [RFC4291] Hinden, R. and S. Deering, "IP Version 6 Addressing Architecture", RFC 4291, DOI 10.17487/RFC4291, February 2006, . [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, DOI 10.17487/RFC4861, September 2007, . [RFC4862] Thomson, S., Narten, T., and T. Jinmei, "IPv6 Stateless Address Autoconfiguration", RFC 4862, DOI 10.17487/RFC4862, September 2007, . [RFC4903] Thaler, D., "Multi-Link Subnet Issues", RFC 4903, DOI 10.17487/RFC4903, June 2007, . Sarikaya & Thubert Expires April 21, 2016 [Page 12] Internet-Draft Address Protection ND for LLN October 2015 [RFC4919] Kushalnagar, N., Montenegro, G., and C. Schumacher, "IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs): Overview, Assumptions, Problem Statement, and Goals", RFC 4919, DOI 10.17487/RFC4919, August 2007, . [RFC5480] Turner, S., Brown, D., Yiu, K., Housley, R., and T. Polk, "Elliptic Curve Cryptography Subject Public Key Information", RFC 5480, DOI 10.17487/RFC5480, March 2009, . [RFC5889] Baccelli, E., Ed. and M. Townsley, Ed., "IP Addressing Model in Ad Hoc Networks", RFC 5889, DOI 10.17487/RFC5889, September 2010, . [RFC6550] Winter, T., Ed., Thubert, P., Ed., Brandt, A., Hui, J., Kelsey, R., Levis, P., Pister, K., Struik, R., Vasseur, JP., and R. Alexander, "RPL: IPv6 Routing Protocol for Low-Power and Lossy Networks", RFC 6550, DOI 10.17487/RFC6550, March 2012, . [RFC6775] Shelby, Z., Ed., Chakrabarti, S., Nordmark, E., and C. Bormann, "Neighbor Discovery Optimization for IPv6 over Low-Power Wireless Personal Area Networks (6LoWPANs)", RFC 6775, DOI 10.17487/RFC6775, November 2012, . [RFC7102] Vasseur, JP., "Terms Used in Routing for Low-Power and Lossy Networks", RFC 7102, DOI 10.17487/RFC7102, January 2014, . [RFC7217] Gont, F., "A Method for Generating Semantically Opaque Interface Identifiers with IPv6 Stateless Address Autoconfiguration (SLAAC)", RFC 7217, DOI 10.17487/RFC7217, April 2014, . [Guide] "Guidelines for 64-bit global Identifier (EUI-64TM)", November 2012, . 8.2. Informative references [I-D.rafiee-6man-ssas] Rafiee, H. and C. Meinel, "A Simple Secure Addressing Scheme for IPv6 AutoConfiguration (SSAS)", draft-rafiee- 6man-ssas-11 (work in progress), September 2014. Sarikaya & Thubert Expires April 21, 2016 [Page 13] Internet-Draft Address Protection ND for LLN October 2015 [I-D.chakrabarti-nordmark-6man-efficient-nd] Chakrabarti, S., Nordmark, E., Thubert, P., and M. Wasserman, "IPv6 Neighbor Discovery Optimizations for Wired and Wireless Networks", draft-chakrabarti-nordmark- 6man-efficient-nd-07 (work in progress), February 2015. [I-D.ietf-6tisch-architecture] Thubert, P., "An Architecture for IPv6 over the TSCH mode of IEEE 802.15.4", draft-ietf-6tisch-architecture-08 (work in progress), May 2015. Authors' Addresses Behcet Sarikaya (editor) Huawei USA 5340 Legacy Dr. Building 3 Plano, TX 75024 Email: sarikaya@ieee.org Pascal Thubert (editor) Cisco Systems, Inc Building D 45 Allee des Ormes - BP1200 MOUGINS - Sophia Antipolis 06254 FRANCE Phone: +33 497 23 26 34 Email: pthubert@cisco.com Sarikaya & Thubert Expires April 21, 2016 [Page 14]