Wednesday, April 15, 2009

Review: An IPv6-Based Identification Scheme

This article presents an IPv6 identification scheme to identify physical objects with
RFID tags. The identification is needed in different fields such as locating objects,
health care monitoring, military operations etc.

Their scheme is based on IPv6 unicast address:

010.Registry_ID[5].Provider_ID[16].0.8].Subscriber_ID[24].0[8].Subnet_ID[16].Interface[48].

(note that the "‘."’ is used as a concatenation operator and X[n] where n indicates the
number of bits used to code the field X).

Register_ID is allocated to organizations responsible for assigning network addresses.
Provider_ID is allocated to Internet service provider. 0[8] future extension.
To identify objects they propose to use the unassigned IPv6 namespace that has the
binary prefix "‘001"’ with two formats:

General ID:
0010.Agency_ID[5].Domain_name[48].0[7].Object_Class[16].Serial_Number[48].

Agency_ID is analogous to registry ID, the agency is responsible for allocating the
identifier. Domain name for company or organization. 0[7] future use. Object class to
identify object types. Serial number ID of an object type.

Pseudo Random ID:
0011.Agency_ID[5].Random_Number[119]

This scheme provides more privacy, it does not reveals the ID of the company and other information. They clearly distinguish between and IPv6 address to locate an object and IPv6 ID
to identify and object. The prefix translation is what they propose to translate between an IPv6 ID (prefix 001) and an IPv6 address prefix (010) which means that the IPv6 ID may be used to
obtain an IPv6 address. Since physical objects are mobile, they propose the following
two methods to track objects:

Name System: (Same ID, multiple addresses)
They propose to use canonical name written in a reverse order in which they are constructed.
They reverse it so it can be used as a URL DNS like. By doing this, they can integrate their scheme in existing systems like DNS.

Serial_number.object-class.company.organization.obj.
DNS query will start at "obj"’ level than it will go from right to left.

When objects moves, we need only to update DNS records which maps a name into an address. When objects moves to a different domain, the new owner of objects should update the DNS record. Since DNS is not suited for updates, a localization service provided by the proxy should handle the update.

Address forward scheme:
They use the home agent approach (see Mobile IP paragraph).
They assume that routers are configured to distinguish identifiers from addresses.
We can search for an object by its ID because routers will translate the IPv6 ID into an IPv6 address by modifying the 3 bits prefix. The ID will remain the same and so the address. Objects of the same owner are assigned to a dedicated proxy. The proxy’s address will have same domain prefix. When a router receives an object ID, it translates it and forwards it to the correspondent proxy according to the domain name. When an object moves, its ID and so its address remains the same. The object updates his home proxy with the new location where it moved recently. It also informs the new proxy about its ID. Routers will forward the packets to the proxy according to the domain name. This proxy will have the same role as a home agent in an IP mobile. The proxy will forward requests to the new proxy where the object has moved.

The approach is very comprehensive specially the mapping between ID and address with the 3 bits prefix and the facility of integration in today’s system without major modifications and without a need to query directories like DNS.
However since objects are usually manufactured in thousands and millions (Gillette raisers) when a container moves from an owner to another. The traffic update will generate a massive overhead between owners.
We are faced to the same problems when dealing with mobile IP. We lost object’s trace during transition from one proxy to another.
Not all companies have the same productions capacities. Small companies manufacturers small number of items which means that small companies will not use the IDs assigned to it, while big companies will exhaust ID in a short time (comparing to small companies). Should small companies share the domain ? This means that proxies of small companies cannot use a routing mask when dealing with IDs and IP addresses.
Two companies can share same domain, these 2 companies will have same prefix and since it cannot apply a mask. A proxy will list all the IDs of owned objects. Proxies will be overloaded then and I/O time query will be slow due to the huge amount of data.
Mobile IP approach what if home proxy or company owner of the domain is closed for economic or other reasons. How to maintain the address forwarding?

Link to the article

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