This document summarizes a presentation about programmable switches and open networking. It introduces programmable switches that can be programmed using P4 to manipulate the data plane as needed. It provides examples of using P4 and programmable switches for tasks like advanced network telemetry, load balancing, and intrusion detection. Finally, it encourages trying open networking with programmable switches from Edgecore and Barefoot, and provides contact information for the presenter.

1. Open Networking and
Programmable Switch
Chun-Ming Ou <jimmy_ou@edge-core.com>
Edgecore Networks

2. Who am I
• ONF Ambassador
• Edgecore Networks
• Open Networking
• Programmable Switch

3. Software is
eating the
world

4. What is programmable switch?
• In open networking, the first we think is SDN
• SDN
– OpenFlow
– SNMP
– REST API
– P4
– etc.
• We can manipulate the data plane as we need by
programming

5. P4
• Programming Protocol-Independent Packet
Processors
• Target device
– BMv2
– Barefoot Tofino
– Broadcom Tomahawk

6. ASIC Independence
P4 compiler
My Station
(Routing Classifier)
L3 Routing
(IPv6 w/ ECMP)
L2 Forwarding
ACL
(Redirect, drop & Pkt in)
fpm backend (Broadcom) Tofino backend (Barefoot)
bcm_demo.bin
Control plane
p4runtime.proto
P4Runtime server
Target driver
Switch ASIC
demo.p4info
Allocate resources to realize the pipeline,
and generate runtime mapping
Generate control
plane contract
bf_demo.bin
demo.p4
Stratum
bmv2 backend
bmv2_demo.bin
Image from ONF

7. 不談場景的
SDN
都是耍流氓

8. When we need programmable switch?
• Enhance Visibility
• Achieve the Design Intent
• Increase network reliability
• Accelerate Innovation

9. SONiC and SAI
Image from SONiC Github

10. Advanced Network Telemetry
Image from Barefoot(https://www.barefootnetworks.com/use-cases/)

11. Sharding
Image from Ucloud Blog

12. How we use programmable switch?
• Clear what you want
• Choose NOS
• Have a p4 program
• Deploy in your network
• Optimize the performance

13. Interface between control plane and data plane
• Transparent broker
interface between
P4Runtime / gNMI /
gNOI to vendor-
specific managers
P4 Runtime
Switch Broker Interface
Node instance
for Chip 1
gNMI gNOI
Node instance
for Chip 2
Chassis
Manager
Flow Write
to Chip 1
Push
pipeline to
Chip 2
Set port
speed on
Chip 1
Restart
chassis
Chassis Switch with two forwarding chips

14. Switch Architecture
Unified ASIC Driver
APIs
Platform Manager
P4Runtime Server
P4Runtime Client
Edgecore Wedge100BF-32X
Barefoot Tofino 3.2Tbps
32 x 100G QSFP28
With BFN-T10-032D and BFN-T10-032Q
Hardware Used
I2C bus, /dev, etc.
C method calls
gRPC (local or remote)
CSP-9550 Server
Barefoot Tofino 3.2Tbps
32 x 100G QSFP28
With BFN-T10-032Q

15. Application of programmable switch
• Advanced Network Telemetry
• Layer 4 Load Balancer
• In-Network DDoS Detection
• Packet generator
• DNS cache
• etc.

16. Edgecore Wedge100BF pipeline
Packet
Queuing,
Replication &
Scheduling

17. Multi-pipeline

18. Recirculate
Packet
Queuing,
Replication &
Scheduling
Packet
Queuing,
Replicat
ion &
Scheduli
ng
Packet
Queuing,
Replicat
ion &
Scheduli
ng

19. P4 program template for header

20. P4 program template (TNA)

21. P4 program example: simple_router.p4 21
header ethernet_t {
bit<48> dst_addr;
bit<48> src_addr;
bit<16> eth_type;
}
header ipv4_t {
bit<4> version;
bit<4> ihl;
bit<8> diffserv;
…
}
parser parser_impl(packet_in pkt, out headers_t hdr) {
/* Parser state machine to extract header fields */
}
action set_next_hop(bit<48> dst_addr) {
ethernet.dst_addr = dst_addr;
ipv4.ttl = ipv4.ttl - 1;
}
...
table ipv4_routing_table {
key = { ipv4.dst_addr : LPM; // longest-prefix match }
actions = { set_next_hop(); drop(); }
size = 4096; // table entries
}
...
apply {
if (ipv4.isValid()) {
ipv4_routing_table.apply();
}
}
...
Ingress pipeline implementation:

22. Simple router example
● Data plane (P4) program
○ Defines the match-action tables
○ Performs the lookup
○ Executes the chosen action
● Control plane
○ Populates table entries with specific
information
■ Based on configuration, automatic
discovery, protocol calculations
action ipv4_forward(bit<48> dst_addr, bit<9> port) {
ethernet.dst_addr = dst_addr;
standard_metadata.egress_spec = port;
ipv4.ttl = ipv4.ttl - 1;
}
table ipv4_routing_table {
key = {
ipv4.dst_addr : LPM; // longest-prefix match
}
actions = {
ipv4_forward();
drop();
}
}
Control plane populates table entries

23. Optimize resource
Image from Ucloud Blog

24. Q&A

25. Want to try open networking?
• Please contact with Edgecore website
With the programmable switch? Barefoot? Trident 4?
Please contact me
• jimmy_ou@edge-core.com

26. Thank You
jimmy_ou@edge-core.com
#Barefoot #Tofino #Tofino2 #P4 #P4lang #OpenNetworking