ICN: A New Approach to Internet Communication

ICN Motivations

• TCP/IP-based Internet is designed for end-to-end communication, using location-based identifiers like IP addresses.
• Internet traffic is experiencing a massive increase in data, with high levels of data replication.
• The shift from wired to wireless networks necessitates better mobile communication support.
• Existing IP address-based systems struggle with location changes, leading to increased overhead for mobility management.

ICN: A New Network Layer Approach

• Aims to address the limitations of IP by providing data more efficiently, supporting seamless mobility, and improving data security.
• ICN transitions the communication model from request-to-location to request-for-content.
• It views the Internet as a vast database and offers a new way of accessing data.

ICN Key Features

• Employs a receiver-driven communication model with queries (interests) and data (responses).
• Uses content identifiers rather than location identifiers.
• Enables in-network caching at network nodes, leveraging routers for caching and other functions.
• ICN's design allows for efficient content naming and retrieval.

ICN Architectures

• Two major ICN architectures: Centralized and Decentralized.
• Centralized:
  • Utilizes a centralized Name Resolution System (NRS) for resolving names and publishing content.
  • Uses a Flat Name Structure with caching at edge routers.
• Decentralized:
  • Includes Named Data Networking (NDN) and Content Centric Networking (CCN).

Named Data Networking (NDN)

• Content is addressed using a hierarchical name structure that resembles file system paths.

NDN Messages & Structures

• Messages:
  • Interest (Query) packets contain information about the requested content, including unique identifiers, security details, and routing hints.
  • Response (Data) packets contain the requested content, metadata, and security signatures.
• Data Structures:
  • Forwarding Information Base (FIB) – similar to routing tables, it maps name prefixes to next hops.
  • Pending Interest Table (PIT) – stores pending queries for efficient response routing.
  • Content Store (CS) – acts as a cache for storing content.

NDN Routing & Forwarding

• NDN's forwarding process involves matching interest names against entries in the FIB to determine the next hop.
• NDN can utilize the same routing algorithms as IP but requires different protocols for managing Interest and Data messages.
• NDN routing tables have a potential for larger size compared to IP's due to the ability to store individual content names.

NDN vs IP Routing Table Comparisons

• IP Routing Table:
  • Limits entries by aggregating individual addresses into prefixes for scalability.
  • Faces challenges with growing table size due to factors like multi-homing, mobility, and traffic engineering.
• NDN Routing Table:
  • Also relies on name prefixes to manage entries efficiently.
  • Leverages "map and encap" techniques to map application names to routable prefixes, typically belonging to ISPs.

NDN Routing vs IP Routing Comparisons

• IP Routing:
  • Essential for packet delivery, requiring perfect routing paths and fast convergence.
• NDN Routing:
  • Acts as a supporting mechanism for content forwarding.
  • Does not need to be perfect and supports a more flexible routing approach.

Loop Detection

• IP:
  • Lacks explicit loop detection mechanisms.
  • Relies on TTL (Time to Live) to prevent loops.
• NDN:
  • Employs PIT to track Interests and utilize unique nonces (random numbers) in each Interest packet to identify loops.

Failure Detection

• IP:
  • Uses one-way traffic and a stateless approach, limiting failure detection capabilities.
• NDN:
  • Tracks response times and PIT entries to identify potential failures.
  • Supports explicit Interest NACK to signal problems upstream.

Multipath Forwarding and Adaptive Forwarding

• Multipath Forwarding:
  • Easier in NDN due to its two-way traffic and datagram state.
• Adaptive Forwarding:
  • Enabled by named data, two-way traffic, and datagram state.
  • Efficiently handles link failures, congestion, and hijacking attempts.

Comparison: Mobility

• IP:
  • Location-bound address system limits mobility support.
  • Faces challenges with latency, unreliability, and cost associated with mobility management.
• NDN:
  • Content-based addressing inherently supports customer mobility.
  • Producer mobility can be addressed through rendezvous points.

ICN's Advantages

• Content-centric addressing: simplifies content naming and retrieval.
• In-network caching: enhances content availability and reduces network load.
• Mobility support: enables seamless mobility for both users and producers.
• Security enhancements: offers robust security features with content signatures and encryption.