Commodity servers equipped with intelligent server adapters (ISAs) are being used as platforms for Network Functions Virtualization (NFV). The network traffic processing required by a specific use case is frequently expressed by forming a chain of Virtual Network Functions (VNFs). This demonstration illustrates that VNFs in the chain can be hosted on the server CPU or on the ISA. It furthermore illustrates that VNFs can be decomposed into components called Micro-VNFs, with the components again being hosted on the server CPU and/or the ISA. A P4 program (compiled to native code running on the ISA) defines the overall semantics of the datapath within an ISA equipped server and expresses how VNFs and Micro-VNFs should be composed within this platform. We show how mechanisms like tunnels and service headers programmed using P4 are employed to establish the VNF service chain across multiple network nodes. David George Lead Engineer, Netronome David George is a lead engineer on the Netronome SDK team and is primarily responsible for Netronome's P4 data plane. He has previously been worked on the SDK simulator and x86 data plane components. He holds a Masters of Electrical Engineering from the University of Cape Town.

1. 1©2016 Open-NFP
P4-based VNF and Micro-VNF chaining for
servers with SmartNICs
David George
david.george@netronome.com

2. 2©2016 Open-NFP
Session Agenda
●
Introduction
●
Design overview
●
A look under the hood
– P4, SandboxC and rules
●
Run-through
– Demo of key features
●
Conclusions + questions
●
(time permitting) A quick overview of SDK6 P4 runtime

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Introduction
●
VNF – Virtualized Network Function
– Network function hosted independent of physical hardware
●
examples: Firewall, intrusion detection
– Chaining a sequence of VNF
●
Micro-VNF?
– Light-weight VNF
– Possible to integrate close to dataplane
●
e.g in kernel, on smartNIC
– examples: telemetry, statistics
●
Goal to illustrate how this can be achieved:
– SmartNIC P4 dataplane using Netronome SDK 6
– Micro-VNFs in sandbox C
– Simple VNFs with libvirt + VFIO
– Other ‘neat’ P4 stuff
●
Why this example?
– Illustrates how simple it can be to solve challenging problems with P4 + SmartNICs:
●
Marshalling data into VNFs
●
Gathering telemetry info + processing statistics
–

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Design/Demo Overview
X86 Host
Micro-VNFs:
Payload scan
Hoptime stats
Linux Net Namespace
VLAN 2
“dumb” NIC
+ bridge
Physical
Interface
TCP path
with metering
Netronome SmartNIC with P4+C Dataplane
VNF0:
NetDev L2 Bridge
in VM
VFIO 1
VNF1:
DPDK L2 Bridge
in VM
VFIO 0
VFIO 3
VFIO 2
Linux Net Namespace
VLAN3

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Design/Demo Overview (cont.)
●
P4 Dataplane
– Run-of-the-mill parse + match + action + forwarding
●
VNFs: L2 Forwarding “cooked two ways” DPDK and NetDev
– Simple way to illustrate use
– BUT complicated routing:
●
Must be unique per port direction!
●
MicroVNFs:
– VF “Hoptime” statistics
●
Min, max, avg reported between VF send + receive
●
Achieved using custom tunnel
– Simple payload scanner: search for a compile time token
●
Extra points of interest
– Meters
●
Traffic generation:
– VLAN IDs used for routing between VFs
– Linux Network Namespaces to isolate address spaces (all on one host)

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Traffic Generation
X86 Host
Micro-VNFs:
Payload scan
Hoptime stats
Linux Net Namespace
VLAN 2
“dumb” NIC
+ bridge
Physical
Interface
TCP path
with metering
Netronome SmartNIC with P4+C Dataplane
VNF0:
NetDev L2 Bridge
in VM
VFIO 1
VNF1:
DPDK L2 Bridge
in VM
VFIO 0
VFIO 3
VFIO 2
Linux Net Namespace
VLAN3

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Coarse look at P4 design
Parsing
Ethernet
VLAN
Custom “hoptime” header
IP + TCP
Ingress
Process “hoptime”
Metering
Forwarding
Egress
Insert “hoptime”
Translate VLAN Tags

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A look under the hood + demo:

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Conclusions
●
Illustrated simple solution for VNF chaining using P4
●
Showed the potential for implementing Micro-VNFs in C
sandbox
– Support for going beyond the P4 parsed headers in C
– Measurement of VNF processing time
●
Showed how flexibly P4 meters can be used

10. 10©2016 Open-NFP
Github Resources
●
https://github.com/open-nfpsw/p4_vnf_uvnf_demo
●
Includes:
●
P4 , sandbox C & P4 configs
– Building & loading using CLI or PS IDE
●
Host scripts

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Questions?

12. 12©2016 Open-NFP
SDK P4 Runtime Environment
●
Typically programmer studio drives the configuration
– Hitting “debug” programs firmware, load rules, configures meters etc.
●
The RTE ships with python tools and thrift interface for
interacting with P4 Runtime Environment Server via Thrift
RPC
– Allows command line driven loading configuration
– Possible to build a stand-alone application for interacting with design
●
Example: L2 bridge receiving P4 digests and writing table updates

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SDK P4 Runtime Environment (cont)
●
in RTE installation you will find the following:
– thrift/sdk6_rte.thrift
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Thrift interface file, RPC stubs generated from this and can be used
with python, C++...
– thrift/client/RTEInterface.py
●
A python module that provides an abstraction for the Thrift interface
– thrift/client/sdk6_rte_cli.py
●
A swiss army knife command line tool
– thrift/client/digest_listener
●
Example tool for dumping digest events