1. Content Centric Networking
Fred Baker

2. Agenda and comments I am commenting on networking research
Paradigm: identifying and retrieving content, as opposed to talking with computers
Multiple related projects:
Van Jacobson (PARC) Content Centric Networking (CCN)
Lixia Zhang (UCLA) Named Data Networking (NDN)
European projects generally called Information-Centric Networking (ICN)
Giovanna Carofiglio’s work at Alcatel-Lucent, Bell Labs, and Cisco
Numerous others…
The big questions at Tical will be:
Why?
What?
How to experiment with it?

3. CCN in a nutshell Today’s Internet Content Centric Networking (CCN)
CCN advantages
Ever-growing amount of digital info
From point-to-point to (multi)point-to-multipoint info dissemination
Connectivity diversity: multiple devices, heterogeneous networks
Waste of resources in content
replication!
Simplified network
management
Traffic reduction
and localization
Seamless, ubiquitous
connectivity
Congestion reduction
Effective Security
Names not addresses
Packet self-identification
Packet self-certification
Receiver-based transport
Enhanced router storage
Before… …After 3 3

4. Content names and packets
Content items are identified by a unique name and are split into self-identified chunks (packets)
CCN names are hierarchically structured to allow aggregation of routing and forwarding table entries.
E.g. /BellLabs/ICN/talks/reality.avi/chunk0
CCN packets are of two types:
Hierarchical naming scheme, content published in repositories, repositories annouce prefixes they can serve. Data is divided in chunks. A user expresses interest for every packet of the content.

5. CCN Communication Model
/BellLabs/ICN/talks/reality.avi A B
Interest H
/BellLabs/ICN/talks/reality.avi/chunk0
Users generate Interest messages to request content chunk- by-chunk
One Interest retrieves one specific content chunk (Data packet)
Interests are routed towards permanent copies of the content
Data is transmitted only in response to an Interest and follows reverse Interest path
Intermediate nodes transparently cache in-transit Data packets

6. Name-based Routing
Routing can be done in a similar fashion to today’s IP routing:
Routers announce “name prefixes” covering data they are willing to serve
Announcements are propagated through the network via a routing protocol
Every router builds its Forwarding Information Base (FIB)
Component-wise longest prefix match forwarding based on FIB information

7. CCN vs IP Forwarding
CCN IP
CCN FIB (Forwarding Information Base) is used to forward Interest packets toward potential sources. Almost identical to IP FIB.
Content Store enhances buffer memory in an IP router and has a caching function: in-transit Data are stored in order to serve future requests and replaced only when the cache is full.
PIT (Pending Interest table) keeps track of forwarded Interests. Only one entry per “similar” requests is kept. This entry is used to forward Data packets toward interested consumers.

8. CCN node operations Interest packet Data packet Lookup Content Store
Lookup+Update(Add/Change entry) Pending Interest Table (PIT)
Lookup Forwarding Information Base (FIB)
Forwarding
Data packet
Lookup+Update(Remove entry) Pending Interest Table (PIT)
Store in Content Store
Forwarding
Additional operations may be required to verify packets

9. CCN Transport
imdb.com
So the end-user emits a content request by requesting the first chunk with a named interest packet. The interest is forwarded upstream until tehe first hitting cache or the repo and each intermediate node keeps track of the pending interest in a structure called PIT. Once the data chunk is found it is sent back to the user following the reverse path of the interests.
PIT entries play the role of the breadcrumbs allowing to build the reverse path.
The data packet is then cached at each node before the user in order to serve subsequent requests for the same content.
Interests are forwarded along named-based routes (RIB/FIB)
Data are retrieved from the first hitting cache (Content Store)
Chunks of a given content may be retrieved from multiple locations
Interest aggregation on a pending interest (PIT)

10. CCN transport principles
receiver based
Receiver controls Interest rate for a content retrieval based on Data rate (window-based controller), performs loss and congestion control.
natively multipath
Interest may be forwarded along different routes according to different forwarding strategies.
Chunks of the same content may be retrieved from different locations.
coupled with in-path caching
The sender endpoint is not known.
On a path between user and a permanent copy of the content every intermediate node can send the content in response to an Interest.

11. Using CCN/NBN/ICN

12. Threads IoT Model Origin: Google Nest
Enclave communicating with upstream service
Defined gateway (UDP/IPv6 <-> 6LowPAN)
Security managed by architecture
6LowPAN within network

13. Message Queue Telemetry Transport (MQTT): Similar model, but publish/subscribe
Devices communicate with MQTT Gateway
MQTT Gateway is intermediate or temporary data repository
Powered devices: TLS/TCP
Low power devices: DTLS/UDP, sleeping nodes
Data is identified by message identifier
Command to “the light bulbs on the second floor”
Telemetry from “motion sensors on the second floor”
Upstream application unaware of individual sensors or actuators
Publish
Subscribe
Enclave communicating with upstream service

14. ICN: named data pull not push, and no sessions
Sending commands for light bulbs on second floor, interested in telemetry from second floor motion sensors
Enclave communicating with upstream service
Devices communicate with content router advertising a class of names
Router is intermediate or temporary data repository
Data is identified by content name
“Command for the light bulbs on the second floor”
“Telemetry from motion sensors on the second floor”
Upstream application may or may not be aware of individual sensors or actuators
Any system may issue named messages
Systems wanting to receive them send “interest” messages
Interested in commands for light bulbs on second floor, sending telemetry from second floor motion sensors

15. Example application In a hospital, tracking patients
Traditional model:
Sensors in rooms
Nursing station or other system monitoring sensors
IP address, if used, is for a device in the room
But is the room what is important?
Probably not: probably the patient and data type are important
The patient might move!
Privacy – who should have access to patient data?
Different types of sensors – who needs to know their data?
So – name the data for the patient and the type of information
And apply security policies around patient confidentiality

16. Sounds good, but what are the weaknesses?
Predicting names!
Scalabiliy of Inter-Domain Routing
Traditional IP sends data when someone wants to send it
And might send spam or malware
ICN sends data that someone wants when they want to receive it
If they can’t predict its existence or its name, that can be difficult
Data that is predictably generated or in a repository works well
Voice and video are current research topics

17. Discussion…