4.0 KiB
4.0 KiB
Information Centric Networks
Problems with today's Networks
- URLs and IP addresses are overloaded with locator and identifier functionality.
- No consistent way to keep track of identical copies.
- Information dissemination is inefficient.
- Cannot benefit from existing copies
- Can lead to problems like Flash-Crowd effect and Denial of service
- Can't trust a copy received from an un-trusted node
- Security is host-Centric
- Based on securing channels (encryption) and trusting servers (authentication)
- Application and content providers are independent of each other
- CDNs focus on web content distributions for major players
Important requirements for ICNs (Information Centric Networks)
- Accessing named resources - not hosts
- Scalable distribution through replication and caching
- Good control of resolution / routing and access
Content-based Routing for ICNs
Apart from routing protocols that use direct identifiers of nodes, networking can take place based directly on content.
- Content can be collected from the network, processed in the network and stored in the network.
- The goal is to provide a network infrastructure capable of providing services better suited to today's application requirements
- Content distribution and mobility
- More resilience to disruption and failures
Network Evolution
Traditional networking
- Host-Centric communications, addressing and end-points
ICNs
- Data-Centric communications addressing information
- Decoupling in space - neither sender nor receiver need to know their partner.
- Decoupling in time - answer not necessarily directly triggered by a question. asynchronous communication.
Approach
- Named Data Objects (NDOs)
- In-network caching/storage
- Multi-party communication through replication
- Senders decoupled from receivers
Dissemination Networking
- Data is requested by name, using any and all means available (IP, VPN tunnels, multi-cast, proxies etc)
- Anything that hears the request and has a valid copy of the data can respond.
- The returned data is signed, and optionally secured, so its integrity & association with name can be validated (data-Centric security)
- Change of network abstraction from named host to named content (content chunks).
- Security is built in - secures content and not the hosts.
- Mobility is present by design.
- Can handle static and dynamic content.
Naming Data
Solution 1 - Name the data
- Flat - non human readable identifiers
1HJKRH535KJH252JLH3424JLBNL
- Hierarchical - meaningful structured names
/nytimes/sport/baseball/mets/game0224143
Solution 2 - Describe the data
- With a set of tags
baseball, new york, mets
- With schema that defines attributes, values and relations among attributes
Using Names in CCNs (Content Centric Networks)
- The hierarchical structure is used to do longest match look-ups which guarantees
log(n)state scaling for globally accessible data. - Although CCN names are longer than IP identifiers, their explicit structure allows look-ups as efficient as IP's.
ICN Forwarding
- Consumer broadcasts and interest over all available communication media
- Interest identifies a collection of data whose name has the interest as a prefex.
- Anything that hears the interest and has an element of the collection can respond with that data.
ICN Transport
- Data that matches an interest, consumes it.
- Interest must be re-expressed to get new data.
- Controlling re-expressions allows for traffic management and congestion control.
- Multiple (distinct) interests in the same collection may be expressed
ICN Caching
- Storage and caching are integral part of the ICN service
- All nodes potentially have caches. Requests for data can be satisfied by any node holding a copy in it's cache.
- ICN combines caching at the network edge with in-network caching.