Glossary

Address resolution The process of determining the corresponding link-layer address for an IP address on a link.

Ad hoc LoWPAN An isolated LoWPAN, not connected to any other IP networks. Ad hoc LoWPANs make use of unique local IPv6 unicast addresses (ULAs).

Anycast Send a packet from one interface to just one out of a defined set of interfaces.

Anycast address An IP address used by a set of interfaces, usually belonging to different nodes. A packet sent to an anycast address is sent to the nearest interface in that set b;y a routing protocol. An anycast address is formatted in an identical manner to a unicast address. See Section A.2 for more information on IPv6 addressing.

Availability The property that the system is available for use as intended, more specifically the security objective that the system is not subject to denial of service attacks. See Section 3.3.1.

Backbone link An IPv6 link that interconnects two or more LoWPAN Edge Routers in an Extended LoWPAN topology, two or more LLN border routers in the ROLL architecture or two or more backbone routers in ISA100.

Bootstrapping During setup of a node, the establishment of state required for operation that can be performed automatically, without human intervention. With respect to the network configuration, performed by 6LoWPAN-ND, see Section 3.2.

Border routing Routing between two different routing domains. In 6LoWPAN, border routing is performed either by the LoWPAN Edge Router or by a router on the backbone link. Border routing is covered in Section 4.2.7.

Care-of address, CoA An IP address acquired by a mobile node when roaming to a visited network in Mobile IP.

Commissioning During initial setup of a node, the establishment of state required for operation that requires human intervention - see Section 3.1.

Confidentiality The security objective that data is not made available to unintended parties, more specifically, cannot be overheard by unintended listeners - see Section 3.3.1.

Coordinated universal time See UTC below.

Correspondent node A node which a mobile node communicates with in Mobile IP.

Distance-vector routing Routing algorithms based on variations of the Bellman-Ford algorithm. Using this approach, each link (and possibly node) is assigned a cost using appropriate route metrics. When sending a packet from node A to node B, the path with the lowest cost is chosen. The routing table of each router keeps soft-state route entries for the destinations it knows about, with the associated path cost. Routing informationis updated either proactively (a priori) or reactively (on-demand) depending on the routing algorithm.

Duplicate address detection, DAD Automatic detection of configuration errors that lead to interfaces of multiple nodes on a link having the same address. Part of standard Neighbor Discovery (ND). See Appendix A.4, and Section 3.2.2 for how the same effect is achieved in 6LoWPAN.

Extended LoWPAN The aggregation of multiple LoWPANs interconnected by a backbone link via edge routers and forming a single subnet.

Handover A process in which a mobile node disconnects from its existing point of attachment and attaches itself to a new point of attachment. Handover may include operations at specific link layers, as well as at the IP layer, that enable the mobile node to communicate again. One or more application streams typically accompany the mobile node as it undergoes handover.

Home address The IP address of a mobile node on its home network in Mobile IP.

Home agent A Mobile IP router on the home network of a mobile node which performs forwarding for it while the mobile node is roaming.

Home network The network that a mobile node belongs to when not roaming in Mobile IP.

Integrity The property that data stay as intended; more specifically, the security objective that data cannot be altered by unauthorized parties - see Section 3.3.1.

Link A communication facility of medium over which IP nodes can communicate at the link layer (the layer just below IP). In 6LoWPAN, link-local scope refers to communication using a single link-layer transmission. Local refers to an address of a destination considered to be within link-local scope. Non-local is the opposite of local.

Link-state routing Routing algorithm where each node acquires complete information about the entire network, often called a graph. To do this each node floods the network with information about its links to nearby destinations. After receiving link-state reports from sufficient nodes, each node then calculates a tree with the shortest path (least cost) from itself to each destination using e.g. Dijkstra’s algorithm. This tree is used either to maintain the routing table in each node for hop-by-hop forwarding, or to include a source-route in the header of the IP packet.

LoWPAN Edge Router An IPv6 router that interconnects the LoWPAN to another IP network.

LoWPAN host A node that only sources or sinks IPv6 datagrams.

LoWPAN Node A node that composes a LoWPAN, referring to both hosts and routers.

LoWPAN Router A node that forwards datagrams between arbitrary source-destination pairs using a single 6LoWPAN interface performing IP routing on that interface.

IPsec IP security, the standard security architecture for the Internet Protocol - see Section 3.3.3.

Inter-domain routing Routing between different administrative domains. The border gateway protocol (BGP) is used for inter-domain routing on the core Internet.

Interface identifier, IID The part of an IPv6 address used to identify an interface on a link, which must be unique in a subnet. In 6LoWPAN the interface identifier (IID) is created from the link-layer address of the interface.

International atomic time See TAI below.

Internet key exchange, IKE Protocol used with IPsec to dynamically establish a security association between Internet nodes.

Intra-domain routing Routing within the same administrative domain. OSPF and AODV are examples of intra-domain routing protocols.

Macro-mobility Refers to mobility between networks. In 6LoWPAN we consider macromobility to refer to mobility between LoWPANs, such that the IPv6 prefix changes.

Maximum transmission unit, MTU The maximum size of a packet that can be carried in one transmission unit over a link.

Medium access control, MAC A sublayer of the data link layer (DLL) which is responsible for addressing and channel access to a shared medium.

Mesh-Under Refers to multihop forwarding in a LoWPAN using link-layer techniques.

Micro-mobility Refers to mobility that occurs within a network domain. In 6LoWPAN we can consider micro-mobility to refer to the mobility of a node within a LoWPAN where the IPv6 prefix does not change.

Multicast Send a packet from one interface to every one of a defined set of interfaces in one go.

Multicast address An IP address used by a set of interfaces, usually belonging to different nodes. A packet sent to a multicast address is delivered to all interfaces identified by that address (unless that is prevented by packet loss). See Section A.2 for more information on IPv6 addressing.

Neighbor Discovery, ND A protocol used by IPv6 nodes to perform operations between nodes on a link such as address resolution, duplicate address resolution and Neighbor Unreachability Detection. See Section A.3 for a detailed description.

Neighbor unreachability detection, NUD Automatic detection that a neighbor is no longer reachable in the way previously used. Part of standard Neighbor Discovery (ND). NUD may trigger recovery action such as switching to a different default router. See Section 3.2.5 for the way the same effect is achieved in a LoWPAN.

Network mobility Mobility in which an entire IP network moves its point of attachment. Node mobility Mobility in which an IP node moves between points of attachment.

Prefix The first bits of an IP address common to addresses using it. An IPv6 prefix has an associated prefix length, i.e. the number of those bits.

Proactive routing Routing algorithms using a proactive approach build up routing information on node before the routes are needed. Thus they proactively prepare for the data traffic by learning routes to all possible or likely destinations.

Reactive routing Reactive routing protocols store little or no routing information after autoconfiguration of the routing algorithm. Instead, routes are discovered dynamically only at the time they are needed. Thus a process called route discovery is executed when a router receives a packet to an unknown destination.

Roaming A process in which a mobile node moves from one network to another, typically with no existing packet streams.

Route-Over Refers to multihop forwarding in a LoWPAN using IP routing. Routing table A table where routers keep entries with next hop information.

Simple LoWPAN A Simple LoWPAN consists of a single edge router and the set of LoWPAN Nodes on the same subnet.

Stateless address autoconfiguration, SAA An ND techniquewhich enables automatic configuration of host addresses by deriving the interface identifier using link-layer information, usually the EUI-64 of the interface.

Subnet A subnet refers to a group of nodes that have the same IP prefix. All nodes in a subnet are considered to be on the same link. In 6LoWPAN multiple IP hops may be required to connect all nodes on a link because of properties of the wireless link.

TAI International atomic time, an internationally maintained standard monotonic timescale based on the most precise clocks available. The civil time UTC is derived from TAI by occasionally inserting leap seconds to compensate for the irregular rotation of the earth; as of January 2009, UTC is 34 seconds behind TAI. As the progress of TAI is not disturbed by leap seconds, it is more appropriate than UTC for applications such as process control.

Unicast Send a packet from one interface to one other interface.

Unicast address An IP address assigned to a single interface. See Section A.2 for more information on IPv6 addressing.

Uniform resource identifier, URI A compact sequence of characters that identifies an abstract or physical resource, with a structure that contains a URI scheme (such as “http”) as well as certain scheme-dependent elements such as a network location or authority, a path, a query, and/or a fragment identifier. A subset of URIs, the uniform resource locator (URL) provides a means of locating the resource by describing how to access it at a location in the network. The terms URI and URL are rarely distinguished carefully.

UTC Coordinated Universal Time, the basis for the civil timescales used throughout the world, which are modified from UTC by the locally applicable timezone. UTC is based on TAI, but synchronized to the rotation of the earth by the occasional insertion of leap seconds. Often still colloquially designated with the no longer correct name of its historic precursor GMT, Greenwich mean time.

Visited network The network that a mobile node is visiting in Mobile IP when roaming.

Web services A client-server communication paradigm utilizing HTTP for machine-tomachine interaction on the web. See Section 5.3.4 for an introduction to web services and Section 5.4.1 for application to 6LoWPAN.

Whiteboard A conceptual data structure similar to a MIPv6 binding cache which may be supported by edge routers. The whiteboard is used for performing DAD and NUD across the entire LoWPAN. The whiteboard contains bindings for LoWPAN Nodes consisting of owner interface identifier, IPv6 address, timeout, along with transaction ID history - see Section 3.2.2.