Page 40 - 5G Basics - Core Network Aspects

1 Core network aspects

9 Design goals

This clause investigates the design goals of realizing each architectural components of DAN.

9.1 Naming
DAN is recommended to provide a data object with persistent and unique name.

Rationale: DAN names data objects using a naming scheme to identify each data object uniquely. There are
a large number of identical copies of a data object which are distributed in different locations since all DAN
elements have caching capability. Thus, the name of a data object should be persistent and unique so that
users can access a data object simply based on its unique name regardless of its location. Unique name may
represent one single data object, a group of data objects, or a group of identical copies of a data object.
Moreover, since DAN elements use the attributes of a data object, e.g., file extension, to process user
requests and the corresponding responses, DAN should be able to provide a naming scheme which supports
the attributes of the data object.

9.2 Routing

DAN routing scheme is recommended to be scalable to support a large number of data objects. Additionally,
it is recommended to support availability and adaptability.
Rationale: Routing in DAN locates a data object based on its name. It can use either a name resolution process
which translates the name of requested data object into its locator and forward the user request based on
its locator, or simply carry out routing based on the name of the data object without the resolution process.
Routing in DAN uses the name of the data object whose number is estimated to be as high as 10^11 [b-
Koponen]. Thus, the routing scheme in DAN should be scalable to deal with such a large number of data
objects. Also, DAN is recommended to incorporate caching data objects into the routing scheme so that users
take advantage of retrieving a data object from a nearby cache, which provides high availability of the data
object. Moreover, a copy at cache has volatile behaviour since copies are frequently added, deleted, or
replaced in the cache. Thus, a routing scheme in DAN is also recommended to adaptively take into account
the volatile behaviour of copies in the cache.

9.3 Caching

Each network element in DAN is recommended to support a caching mechanism and be also able to inspect
user requests that pass through it so that it can make a decision on user requests and respond using the
cached data objects.

Rationale: To enable DAN elements to respond user requests, caching is a compulsory part of DAN. DAN is
recommended to offer a caching mechanism which benefits from the recognition of user requests. For
instance, since all DAN elements can cache any data object passing through them, a caching decision is
preferably made by the DAN elements. It is known as on-path caching which provides an implicit mechanism
for DAN to distribute more data objects to the places where there are heavy requests with the minimum
extra overhead of the caching mechanism.

9.4 Security

DAN is recommended to provide users with a security mechanism to verify the origin and integrity of data
objects.

Rationale: The user of DAN retrieves a data object not only from an original copy provider but also from any
network elements with the cached data objects. Since data objects can be maliciously modified, every data
object in DAN should be signed by its publisher so that a user of the data object can verify the validity of the
data object based on the signature. Since the data object is expected to be created by the publisher and is
expected to be accessed by an unspecified number of users, an asymmetric cryptography is recommended
to be used in the verification. To verify the signature of a data object, individual users should know the
publisher's public key so that they can verify the origin and integrity of the data object. Therefore, DAN should
support a mechanism which distributes the publisher's public key to the consumers of data objects.

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