What is an Entity in naming?
A resource such as computer
What is a Name?
A string of bits or characters (possibly human-readable) bound to entity attributes.
What is Name Resolution?
Translating a name into the attributes of an entity.
What is an Access Point?
A special kind of entity needed to operate on an entity.
What is an Address?
Name of the access point
Why use location-independent names?
Entity may have multiple access points, access points may change, addresses shouldn’t be regular names.
What is the primary function of a naming system?
Name resolution - looking up entity attributes from a given name.
What are secondary functions of naming systems?
Creation, Deletion, Listing, Organisation of bindings.
What are the 3 classes of naming systems?
Flat naming (no structure), Structured naming, Attribute-based naming.
What is Flat Naming?
Entities referred to by identifier with no meaning or structure.
What is Broadcasting for name resolution?
Broadcast the ID requesting entity to return its address. Doesn’t scale beyond LANs and requires all processes to listen.
What is ARP?
Address Resolution Protocol - broadcasts ‘Who has this IP?’ to find MAC address.
What are Forwarding Pointers?
When entity moves from A to B
What are problems with Forwarding Pointers?
Long chains not fault tolerant
What are SSP Chains?
Stub-Scion Pairs - forwarding pointers using client stub and server stub.
What is the Home-Based Approach?
Mobile host uses fixed IP. Communication directed to home agent. When host moves
What is a Care-of-Address?
Temporary foreign address mobile host gets when moving to another network
How does Mobile IP work?
Packet sent to home agent. If host local, forward. If not, tunnel to care-of-address. Inform sender of new location.
What does the Home-Based Approach provide?
High degree of location transparency
What are problems with Home-Based Approach?
Fixed home address, communication latency increase, poor geographical scalability.
What is a Distributed Hash Table (DHT)?
Nodes in logical ring. Each node has m-bit ID, each entity has m-bit key. Key k stored on node with smallest ID ≥ k.
What is a Finger Table?
Each node p has table with m entries: FT_p[i] = succ(p + 2^(i-1)). Enables O(log n) lookup.
How does DHT lookup work?
Forward request to node j where FT_p[j] ≤ k < FT_p[j+1].
What is Hierarchical Naming?
Large-scale search tree where network divided into hierarchical domains
