1. Naming Examples
UUID (universal unique ID) – 128 bit numbers, locally generated, guaranteed globally unique
Uniform Resource Identifier (URI)
URL (uniform resource locator) – location dependent
E.g.,
Name resolution via DNS (Domain Name Service): URI  IP
URN (uniform resource names) – location independent
E.g., urn:isbn:

2. Naming Principles Network entities (by Saltzer) Naming issues:
Services (and data)
Hosts (endpoints)
Network attachment points
Paths (routing paths)
Naming issues:
Mobility
Multi-homing
Replication
Security
Scalability

3. Host Identity Protocol (HIP)
128-bit host identity tag (HIT)
Process
Process
Transport
<IPaddr, port>
Transport
<HIT, port>
IP Layer
HIP Layer
<IPaddr>
<HIT>
IP Layer
<IPaddr>
HIT replaces IP address as a name
of a system

4. How It Works? Client app Client app DNS library DNS Transport
HIT
DNS request
Client app
Client app
DNS
library
DNS
DNS reply = pubkey (P)
send(HIT)
HIT=hash(P)
IPaddr
Transport
Transport
HIP
daemon
4-way authentication
HIP
daemon
HIT
HIP Layer
IPaddr, P
HIP layer
send(IPaddr)
IPsec
IPsec

5. Layered Naming Architecture (LNA)
Process
Process
SID↔EID
<SID>
Transport
<IPaddr, port>
Transport
<EID, port>
IP Layer
EID↔IP
<IPaddr>
<EID>
IP Layer
<IPaddr>
Should name each individually:
Service identifiers (SIDs) name services/data
Endpoint identifiers (EIDs) name hosts
IP addresses name attachment points
Ignore paths (router involvement)

6. How It Works? “DNS” Client app Client app SID↔EID SID↔EID LNA daemon
DNS request
“DNS”
Client app
Client app
DNS reply = sid
send(sid)
SID↔EID
eid = get(sid)
SID↔EID
put(sid, eid)
put(eid, IP)
LNA
daemon
DHT
send(eid)
Transport
IP = get(eid)
Transport
send(eid)
EID↔IP
EID↔IP
Intermediary (IPi)
send(IPi) IP IP

7. Take Away Don’t bind to lower-level IDs prematurely
Host mobility and renumbering (HIP)
Service and data migration
Resolution (binding) of name need not point to object itself, but can point to its delegate
Resolution can point to intermediaries who process packets on behalf of the named target
Examples
HIP: one layer; IDs identify machines
LNA: two layers
EIDs identify machines
SIDs identify everything else

8. UIA Naming Flat (personal group level) Resolution Routing:
User can put “a user friendly” name to each device
iPod.Alice, Camera.Bob
Each “personal” device has a unique ID (EID)
Resolution
Mapping (user name  EID via log records) is disseminated whenever connectivity is available
Local resolution (assuming full replication)
Routing:
Routing packets to the EID node??
Source routing using a P2P overlay network

9. Service Discovery Lots of services dispersed across the network
How to find who has what services?
Example systems: Jini, JXTA, SLP, UPnP, Bonjour Salutation, INS, Twine, etc..

10. Directory Information

11. Directory Architecture

12. Query Expressiveness

13. Query Routing Application level routing Network level communication
DHT-based
Twine, Chord, CAN, Pastry
Loosely-consistent DHT
JXTA, Freenet
Flooding
Gnutella
Network level communication
Unicast communication with a Central server
Web-services, Napster, INS, Jini, SLP
Multicast communication
Jini, SLP, UPnP