Software Defined Networking

Innovated to accelerate the standardization and innovation of the networking discipline.

Control requirements led to great complexity:

• isolation -> vlan, acl
• traffic engineering -> mpls, ecmp, weights
• packet processing middleboxes -> firewalls, NATs
• payload analysis -> deep packet inspection

Needed to abstract the control plane for simplicity of the discipline.

Legacy switches had hardware (ASIC) and software (JUNOS routing processes).

A Clean Slate 4D Approach - introduced problems with legacy approach

Ethane - Took 4D and put it into practice with OpenFlow

• Discovery (how does centralized controller find out about new server)

Key innovation was an abstraction over switches, Match Action Table

Match Action Table

Key abstraction to unify different kinds of devices in networking ecosystem:

Router

• match: longest destination IP prefix
• action: forward out a link

Switch

• match: destination MAC address
• action: forward or flood

Firewall

• match: IP addresses and TCP/UDP port numbers
• action: permit or deny

NAT

• match IP address and port
• action: rewrite address and port

Reconfigurable Match Action Table

Adds "compiler" to open flow to parse control flow and configure rules.

Read about P4 Abstract Model