Explore the business benefits of content-centric networking

Content-centric networking architecture

Traditional data packets carry source IP, destination IP and payload. Each IP address is tied to a device on the network. Routers use algorithms and tables to forward packets toward a physical location. Neither the network nor the router knows about the actual content.

In contrast, content-centric networks route information based on the name of the content -- called the named data object. CCN relies on two different packet types:

• Interest packet. An interest packet is a type of request message with a name prefix and all the necessary information about the requested content packet. The job of the interest packet is to move through the network and request the content packet until the user request has been processed.
• Content packet. A content packet carries content data, but with a cryptographic signature. This is analogous to data packets in traditional IP, but because none of the data packets in a content-centric network has an IP address. Each packet exhibits a unique label that specifies its type.

CCN relies on the following three components:

• A content store.
• A pending interest table (PIT).
• A forwarding information base (FIB).

All function at each node -- a server or a router.

Content store

The content store is a router-level cache that holds numerous content packets not by their addresses but by their names. In traditional IP, cache is optional at endpoints.

When an information packet arrives at a node, the forwarding engine checks its content store for the content packet. If found, the node sends the content packet to the user through the gateway, the path the interest packet came from.

PIT

The forwarding engine uses PIT if the content store does not have the content packet it is searching for. PIT is a log of records of all forwarded interest packets that have not yet been satisfied.

PIT checks for similar interest packets in the network. The forward engine diverts the content packet to the same route as previous interest packets. If the content store and PIT do not contain any information about the interest packet, the forwarding engine uses the FIB.

FIB

The FIB uses protocols and algorithms to perform routing at each node. It is a name-based routing table that provides general information about the current location of the content package. FIB maps content name prefixes on the longest prefix match, somewhat similar to IP routing.

CCN uses a different set of protocols to retrieve content packets from the network. The same protocols perform additional tasks that make the network faster and secure.

Content-centric networking implementation

In content-centric networking, endpoints communicate through the content name data rather than IP addresses. Nodes forward interest packets based on name prefixes and return content messages. Data becomes independent of the location.

Content-centric routing protocols fetch content packets and arrange them in the correct order for the user. Each node in a content-centric network must copy the information about every packet that travels through the network for future use.

An interest packet arrives at every node in the network until it finds the respective content packet. A CCN forwarder runs a specialized program known as a forwarding engine. It is analogous to a traditional router that relies upon a microprocessor and storage.

Content-centric networking supports native in-network content caching, hop-by-hop at each node. It is a major business benefit for IT leaders because native caching is not present in traditional IP networks. Teams are needed to set up an external cache system.

ROI considerations of content-centric networking

Before deploying CCN, ensure it will offer a significant ROI. Otherwise, CCN implementation and maintenance can burn cash and yield results inferior to those of traditional networks.

Enterprises should evaluate the following factors to ensure a CCN investment is worthwhile.

Business-case development

Enterprises must have a justification model for a content-centric network. Once they know why they want to implement CCN, the next steps are to assess operational costs, overhead and efficiency issues. Some enterprises choose to deploy CCN for small research projects, IoT clusters, edge computing environments and smart factories. CCN can be a good choice for startups as well.

Resource allocation

Estimate and allocate resources for phased CCN deployment. IT budgets include hardware upgrades, caching infrastructure, software deployment and staff training. Don't ignore testing and maintenance costs.

Risk assessment

Traditional IP is supported by a huge and diverse vendor community. That's not the case for CCN, however. Enterprises interested in CCN should consider a risk assessment framework. Identify, evaluate and document potential risks to help IT teams prepare mitigation strategies and avoid management complexity.

Budget implications

Cache -- a key ingredient in CCN -- is a major contributor to increased IT budgets. A large cache size can accommodate more content, but deployment costs skyrocket. On the other hand, a smaller cache results in less content volume. A tradeoff exists between the cache size and deployment costs. PIT and FIB track many moving content objects in the network. Despite offering various advantages, PIT and FIB tables pose problems for computational power, memory allocation and costs. PIT and FIB maintenance is another issue.

Cost-benefit analysis

CCN offers a variety of benefits -- such as network caching, reduced latency and increased security -- but these upsides must be balanced against the costs of deploying the technology. One way around this is to evaluate recent experiments that achieve scalability by using smaller tables that list anonymous interests rather than heavy tables.

Advantages of content-centric networking

IT leaders are interested in CCN because its unique features can optimize network performance, particularly for enterprises whose customers and users view large-content video and audio files. In these cases, copied content files speed up the users' experience. Caching handles temporary spikes in demand and keeps a door open for future requests.

CCN offers several benefits that improve network performance.

Reduced latency

In a traditional IP network, the source address is key. Content-centric networks, on the other hand, make content available and accessible at multiple nodes in the network, not just the server. Intermediate caching reduces hop count. Multiple users can access the same nearby node to obtain the content rather than having their requests routed to servers that might not be nearby.

Traffic management

In the wake of increased demand, traditional networks juggle multiple repetitive requests from packets, resulting in congestion. CCN uses interest aggregation -- where only a single interest packet is forwarded for the same request. The rest are collapsed into a single request. Forwarding single requests eliminates duplicate traffic over long-distance links. The result is reduced bandwidth consumption and a lower likelihood of congestion.

Load distribution

Content-centric networks distribute loads more efficiently than traditional networks, where the original server bears most of the load. Content stores and intermediate nodes function as mini-servers, managing multiple requests, especially for popular content.

Improved network performance

FIB shares the current location of the content on the internet rather than the original host address. Content can be cached at multiple nodes, and interests can be aggregated.

Low redundancy

PIT consists of unsatisfied entries of interest packets. Once content is returned, the entry is deleted to avoid redundancy within the network. In addition, interest satisfaction rate must be tracked. A high interest satisfaction rate indicates better network performance.

Data encryption

In addition to content data, each content packet is returned with its cryptographic signature. In traditional IP networks, another protocol encrypts routing paths. CCN safeguards individual data packets, independent of its routing path.

Reduced loss

Traditional IP wireless networks can lose information. If a packet is lost in a content-centric network, nearby nodes do not need to request the source. Instead, they can use copies of the packet -- retained in their content store database -- for retransmission.

Accessibility

Because content can be stored throughout a content-centric network -- each node holds a copy of the content, reducing error rates -- information is more accessible.

Bandwidth optimization

PITs group interest packets with similar features. A single node can route all the traffic for a given interest, thereby reducing the bandwidth required to satisfy each content request. Keeping track of the bytes that no longer have to be transmitted using longer paths helps organizations understand the real-time benefits of CCN.

Best practices for content-centric networking migration

CCN was developed to support IP networks; the best adoption practice isn't to replace the existing IP network, but to integrate CCN where it makes sense. Before implementation, however, enterprises should evaluate some essential principles for successful CCN migration.

Organization readiness

Assess if the enterprise is ready for CCN. Storage capacity must be expanded to support widespread caching, PIT and FIB. Network teams must learn to build a hierarchical naming schema, configure PIT and FIB, and perform interest forwarding. Data-level encryption and the need for verification make network security knowledge mandatory. Because CCN is relatively new, senior staff might lack expertise. Targeted training is a must.

Hybrid network infrastructure

Traditional IP and content-centric networking is interoperable; CCN's functionalities overlap with IP layers and run on existing hardware. For example, some enterprises run name-based networking over Ethernet, Wi-Fi and cellular links. Interest and content packets can be encapsulated into TCP/IP and the User Datagram Protocol.

High-redundancy applications

Content-heavy sites use content delivery networks -- networks of geographically dispersed servers -- to speed up the transmission of information to users. CCN can establish CDNs for enterprises using the networking layer of the OSI.

Content-centric networking security

Content-centric networks are prone to attacks unseen in traditional networking. Enterprises must be aware of the potential security threats of CCN and ways to mitigate them.

Mandatory data signing

CCN professionals must verify cryptographic signatures against a third-party record to confirm the content's origin. Hackers use forged keys to sign. Continuous certification programs are required to mitigate such attacks.

Cache security

Content-centric networks have unique cache poisoning and spoofing specific to them. Hackers produce misleading content and use malicious nodes in the network to distribute corrupted content. To combat these attacks, institute a strategy of encrypted name components, content authentication systems and strict naming schemes.

Flooding detection

Interest flooding attacks, where hackers send large numbers of interest packets with unsatisfiable requests, mimic classic DoS attacks. Hackers trick the cache, exhaust PIT entries and manipulate FIB-based prefixes to increase upstream traffic and reduce bandwidth. Set threshold limits for PIT and FIB. Enable automatic alert generation for abnormal values. Other options include satisfaction-based suppression and access control strategies.

Content-centric networking optimization

There are no universal optimization guidelines for content-centric networks. However, enterprises can focus on improving the performance of the content store, PIT and FIB to ensure overall network performance.

PIT and FIB management

Overflow in PITs and FIBs physically manifests as network congestion, high latency, dropped interest packets and memory stress. Use timeouts on interest packets and aggregate them more. Another manual fix is to monitor memory and storage for PIT and FIB.

Caching strategies

Caching impacts content-centric networking costs. Based on high-redundancy workflows, algorithms cache content based on interest frequency and recency. Maintain a high cache hit ratio in content-centric networks.

Latency reduction

Modern algorithms reduce latency in IoT-based content-centric networks by strategically storing the content in a node that lies nearest to the IoT device.

SDN

Integrating SDN with CCN enables dynamic and optimized control in forwarding interests and content object storage.

Venus Kohli is an engineer turned technical content writer, having completed a degree in electronics and telecommunication at Mumbai University in 2019. Kohli writes for various tech and media companies on topics related to semiconductors, electronics, networking, programming, quantum physics and more.