Some of the focus: local control planes centralization
Some solutions of SDN
VPN (widely adopted solution of WAN)
VLAN (virtualization of address spaces)
The idea of using SDN to create virtual networks: (NSDI’14 T. Koponen)
Datacenter switching fabric (leaf-spine topology)
Leaf: ToR (Top of Rack) switch
Spine: Aggregation switch; usually two for resilience
Two hops from any rack to any other rack through a leaf-spine-leaf
Traffic engineering
Examples: Google B4 (SIGCOMM’18); Microsoft SWAN (SIGCOMM’13)
MPLS-based traffic engineering is local; not globally optimal
Centralizing the decision-making process and rate-limiting traffic, and
differentiating classes of traffic, Google and MS reported the link
utilization to be nearly 100%.
SD-WAN
SD-WAN is a WAN solution that uses SDN to provide a centralized control
plane for a WAN.
The most common approach is MPLS-BGP VPNs. SD-WAN is an alternative with
centralized control.
MPLS requires significant local configurations on both customer
sites and provider sites.
SD-WAN realizes centralized configuration.
Security: encrypted tunnels between edge sites.
Conventional VPN needs backhaul (travel to the central site
before sending out to the Internet); For SD-WAN, it doesn’t
need, as the data plane remains fully distributed
Access Networks
Passive Optical Networks (PON) for fiber-to-home networks; Radio Access
Networks (RANs) for cellular networks
Challenges: transform purpose-built devices for Access Networks to
bare-metal hardware for software control.
Concept: SD-RAN (5G-empowered edge cloud; implement SDN in RANs)
Network Telemetry
INT: In-band Network Telemetry
INT is a framework for collecting telemetry data from the data plane
of a network. It encodes the telemetry information into packet
headers. Each packet collects measurement data as it traverses the
network.
INT can be used for network debugging, traffic engineering, and
performance monitoring.