21 Dec 2015
Network Wide Decision Making: Toward A Wafer Thin Control Plane
https://www.cs.princeton.edu/~jrex/teaching/spring2005/reading/wafer-thin04.pdf
refactoring of IP control plane to provide direct expressibility and
support for network-wide goals
- the management plane
- stores and analyzes measurement data from the network and generates
the configuration state on the individual routers
- the control plane
- consists of network-wide distributed algorithms that compute parts
of the state in the date plane. a primary job of the control plane is
to compute routes between IP subnets
- hard-wired state
- still other state is hard-wired in the router software, as default
value or parameters or algorithms
1.2 Cobbling Together a Network-Wide View
TE, planned maintenance, requires network-level understanding of the
traffic matrix — the observed volume of traffic from each
ingress point to each egress point
operator must use scripts … ACL, blackhole routers that form the
network’s perimete defense to prevent manual provisioning changes from
accidentally opening up a security vulnerability.
2.1 Tomorrow’s Dissemination and Decision Planes
- driven by a principle of network-level expressibility
- the architectural intent and operational constraints governing
the network should be expressed directly, and then automatically (via
protocols or programmatic interfaces) translated to assign roles and
functionality to individual routers
- Dissemination plane
- objective is the timely, reliable dissemination of information to
and from the network elements
- Decision plane
- objective is to make all decisions driving network behavior,
including reachability, routing, access control, security, and
interface configuration
- Two-phase commit
- The data plane could also enable transactional configuration
changes, such as a two-phase commit, to allow decision logic to
synchronize changes to the networks
3. Illustrative Examples
3.1 Joint Optimization of Multiple Metrics
3.3 Visibility Across Layers