zenoh -- the ZEro Network OverHead protocol
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This document introduces Zenoh, a new data-centric networking protocol being developed by ADLINK Tech. Inc. Zenoh allows applications to asynchronously read and write data associated with URIs and supports pub/sub and storage/query models. It is designed to unify data sharing across all types of devices, including extremely constrained ones. Zenoh provides reliability, load balancing, and a small protocol footprint to enable connectivity in resource-limited environments. A live demo is available to showcase Zenoh's capabilities.
![Key Highlights
Protocol implementation for a
8-bit micro-controllers takes
300 Bytes of RAM and has
wire-overhead of 4 bytes for
data samples
7 6 5 4 3 2 1 0
+-+-+-+-+-+-+-+-+
|R|S|P| SDATA |
+---------------+
~ SN ~
+---------------+
~ RID | SID ~
+---------------+
~ PRID ~
+---------------+
~ [Payload] ~
+---------------+](https://image.slidesharecdn.com/2019-190502145748/85/zenoh-the-ZEro-Network-OverHead-protocol-23-320.jpg)
zenoh -- the ZEro Network OverHead protocol
- 2. Context
- 3. Internet protocol For historical reasons, internet has been built on a host-centric communication model. (machine-to-machine)
- 4. The Internet today Most of the application on the internet today are data / content centric. What matters to the user is the data not as much who has it…
- 5. Internet protocol The internet protocol is inherently one-to-one. Broadcast and multicast communications are not viable in wide networks. Thus the diffusion of the same data to multiple consumers is very inefficient.
- 6. NDN / CCN NDN is based on a data centric networking paradigm. Data samples are identified with hierarchical names. NDN is Inherently Pull and best suited for static data. Named Data Networking Content Centric Networking /com.adlink/fr/employees/olivier.hecart
- 7. DDS is a great data centric technology which embraces powerful concepts like strong decoupling between publishers and subscribers. But DDS has been designed for small to medium systems and suffers from major scalability issues on larger systems. It is push based which makes uneasy to retrieve specific data or to properly filter data streams. Data Distribution Service
- 8. The Internet of Tomorrow With the raise of IoT, the different devices connected to the internet use very heterogeneous networking technologies (TCP/IP, BLE, 3G, 6LowPan, …). Some endpoints are extremely constrained w.r.t computational, communication resources as well as energy.
- 9. Internet scale data-centric protocol that unifies data-sharing between any kind of device including those constrained with respect to the node resources, such as computational resources and power, as well as the network.
- 10. Conceptual Model zenoh provides a data-centric abstraction in which applications can read and write data autonomously and asynchronously. The data read and written by zenoh applications is associated with one or more resources identified by a URI. DDS Global Data Space ... Data Writer Data Writer Data Writer Data Reader Data Reader Data Reader Data Reader Data Writer R1 R2 R i Rn -- These are Resources /myhouse/floor/1/musicroom/LightStatus /myhouse/floor/2/musicroom/LightStatus /myhouse/floor/2/bedroom/erik/LightStatus -- These are Selections /myhouse/floor/2/bedroom/*/LightStatus /myhouse/**/LightStatus /myhouse/**
- 11. Conceptual Model Data can be pushed to subscribers and storages and be queried from storages. zenoh pub/sub protocol (push) storage/query protocol (pull) Publisher SubscriberStorage write / stream subscribestore query
- 12. Conceptual Model Data can be pushed-to, pulled or queried-from applications periodically or asynchronously.
- 13. Routing Adaptative, fault tolerant, brokering and routing.
- 14. Live demo
- 15. Reliability & Ordering Z1 Z2 Z6 Z3 Z5 Z4A1 A2 application-to-application reliability first-to-last-broker Zenoh supports 3 levels of reliability : • Hop to hop reliability. Ensures reliability and ordering when NO failures. • App-to-app reliability. • First-to-last-broker reliability. More scalable than app-to-app reliability.
- 16. Load balancing & Fault tolerance Clusters Partitions Resource names to partition ids uniform hashing 0-63 64-127 128-191 192-255 0-63 64-127 128-191 192-255 0-63 64-127 128-191 192-255 P S
- 17. Zenoh clients • Low footprint C client • OCaml client • Python client • Bash client
- 18. A piece of code Publisher : z = zenoh.connect('127.0.0.1:7447') pub = z.declare_publisher('/demo/hello') pub.write('Hello world'.encode()) Subscriber : z = zenoh.connect('127.0.0.1:7447') z.declare_subscriber(‘/demo/**', lambda rid, data: print('received {}'.format(data.tobytes().decode())))
- 19. Performance
- 20. Throughput 0 3500 7000 10500 14000 8 16 32 64 128 256 512 1024 2048 4096 8192 16384 zenoh NATS Cyclone DDS Mbps
- 21. Key Highlights
- 22. Key Highlights Extremely Resource Constrained Environments Defined the most wire/power/memory efficient protocol in the market to provide connectivity to extremely constrained targets Support for: - Peer-to-peer and brokered communication - Batched data and deltas - Ordered reliability and fragmentation - Queries zenoh zenoh 6LowPAN 802.15.4 BLE 2G/3G/ LTE Unspecified API App App App … Application TCP UDP IP
- 23. Key Highlights Protocol implementation for a 8-bit micro-controllers takes 300 Bytes of RAM and has wire-overhead of 4 bytes for data samples 7 6 5 4 3 2 1 0 +-+-+-+-+-+-+-+-+ |R|S|P| SDATA | +---------------+ ~ SN ~ +---------------+ ~ RID | SID ~ +---------------+ ~ PRID ~ +---------------+ ~ [Payload] ~ +---------------+