The document discusses using the RINA networking model to enhance the Project Clearwater IMS core. It describes prototyping HTTP and SIP traffic over RINA, and potential benefits like built-in fault tolerance, mobility, and multi-tenancy support. Future work could explore running additional protocols like Diameter or a service mesh over RINA. An interposer approach is also outlined to enable legacy applications to use RINA transparently.

1. Clearwater on RINA
Matt Williams
Metaswitch Networks
22 February 2018
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2. Agenda
• Background
• Why RINA?
• RINA Enhancements
• RINA Futures
• Interposer Approach (if time)
• Please ask questions!
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3. Background
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4. What is Clearwater?
• An implementation of IMS built using web
development methods to provide voice, video and
messaging services to millions of users.
• Architected from the ground up for massively
scalable deployments within virtualized public or
private elastic compute clouds.
• Combines the economics of over-the-top (OTT)
style service platforms with the standards
compliance and reliability expected of telco-grade
communications network solutions.
• Web services-oriented design makes it ideal for
instantiation within NFV.
• Provided as open-source (Project Clearwater) and
commercially maintained and supported variant
(Clearwater Core)
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5. TADHack & ARCFIRE “RINA Rumba” Challenge
• TADHack
o Annual global hackathon (plus local mini hackathons)
o Held at sites across world, including Madrid
o Generally, Telecoms application focus
• ARCFIRE “RINA Rumba” Challenge
o “a TADHack application works across 3 nodes connected through a RINA network”
o IRATI and rlite implementations – we chose rlite
• Team of 2 over a weekend, made possible by
o Open-source
o Great support
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6. Why RINA?
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7. Why RINA?
• Clean slate – opportunity to avoid need for lots of “work-arounds” in TCP/IP-based solution
o Service discovery – implemented through DNS SRV (or proprietary, e.g. service mesh)
o Server failover – implemented at application level
o Authentication and encryption – uses TLS, but requires lots of application involvement
o Head-of-line blocking – solved by SCTP (if protocol supports), or use multiple TCP connections
o Policy enforcement – addressed by firewalling and IP ToS/DSCP
o Mobility – e.g. as addressed by GTP in LTE EPC
• Network management – in particular in multi-tenancy situations
• Performance (maybe)
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8. RINA Enhancements
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9. Project Clearwater Architecture (pre-RINA)
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• Project Clearwater
• IMS core (+ extras)
• Open-source (GPLv3)

10. Project Clearwater Architecture (HTTP over RINA)
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• HTTP Client
o libcurl
o “open connection” hook
o override for RINA
o recv -> read
o send -> write
• HTTP Server
o libevhtp
o built on libevent
o register for RINA events

11. Project Clearwater Architecture (SIP over RINA)
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• SIP (Client and Server)
o PJSIP
o pluggable transports
o new RINA transport
o recv -> read
o send -> write
• Sprout
o Route headers
o transport=RINA

12. Prototype Deployment
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• Amazon AWS
• EC2 t2.small
• Ubuntu
• rlite
• rlite-shim-udp4

13. Configuration
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14. HTTP Traffic
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15. SIP
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16. RINA Futures
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17. Project Clearwater & Clearwater Core
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Project Clearwater
Open source project
Freely available
Actively maintained/supported by community
IMS core
(Partial) HSS
XDMS
WebRTC
P-CSCF
Self-service portal
(Some) VoLTE MMTel TAS
RINA (prototype, via patch)
Clearwater Core
IMS Core VNF
Hardened & tested by Metaswitch
Maintained and supported by Metaswitch
I-CSCF
S-CSCF
BGCF
Not RINA (yet?)

18. Other Protocols over RINA
• HTTP and SIP can now be over RINA
• Clearwater also speaks
o External
o ENUM (DNS)
o to resolve TEL URIs to SIP URIs
o Cx/Diameter to the HSS
o to retrieve subscriber data
o Rf/Diameter to the CDF
o for offline billing
o Internal
o Memcached protocol
o for distributed storage
o Thrift to Cassandra
o for subscriber profiles
o etcd protocol
o for clustered configuration
• Would need third-party RINA NEs
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19. Fault-tolerant servers
• Clearwater divided into
o Stateless compute processes
o (Simple) stateful datastore processes
• Horizontally scalable
• On failure of a compute process
o Route to another (identical) process
• On failure of a datastore process
o Route to a backup (replicated) process
• Supported by RINA architecture
o …but not yet implemented in rlite
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Datastore
Process A
Datastore
Process B
Datastore
Process C
Compute
Process 1
Compute
Process 2
Compute
Process 3
Replicate

20. RINA via Service Mesh?
• Microservices-based solutions consist of tiers of nodes with communications between them
• These communications need to
o discover the correct nodes to talk to
o load-balance between them
o retry on failure, back off on overload
o be secure.
• Most microservice architectures use a service mesh proxy for this, e.g.
o Linkerd
o Istio
o Conduit
• (Currently, Clearwater has this function built into the applications themselves)
• RINA-enabling a service mesh proxy (DAF?) would
o give new microservices the benefits of RINA
o avoid needing to modify the code
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21. Interposer Approach
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22. BSD Sockets/POSIX
BSD
Sockets/
POSIX
Process
Kernellibc System CallsBSD Sockets/POSIX Calls

23. BSD Sockets/POSIX
BSD
Sockets/
POSIX
Process
Kernellibc System Calls
gethostbyname
socket
connect
read/write or send/recv

24. librina
RINA
Process
Kernellibc System Calls
librina-
api
rina_open
rina_register
rina_flow_alloc
read/write

25. RINA Interposer
BSD
Sockets/
POSIX
Process
Kernel
libc
RINA
Interpose
r
librina-
api
System Calls
gethostbyname
socket
connect
read/write or send/recv
IP setup and
read/write
RINA setup
Config
Files

26. Prototype in action…
$ RINA_DIF=normal.DIF RINA_LOCAL_APPL=nc RINA_REMOTE_APPL=homestead-server
LD_PRELOAD=$(pwd)/libinterposer.so nc 5.6.7.8 5678
socket(2, 1, 6)...
RINA_DIF=normal.DIF, RINA_LOCAL_APPL=nc => RINA interposer enabled!
rina_open()...
...returns 3
...returns 3
connect(3, 0xed5270, 16)...
RINA_DIF=normal.DIF, RINA_LOCAL_APPL=nc, RINA_REMOTE_APPL=homestead-
server => RINA interposer enabled!
rina_flow_alloc("normal.DIF", "nc", "homestead-server", NULL, 0)...
...returns 0
...returns 0

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