Community-Lab introduction

    - Provides a familiar and flexible env for researchers.
  - Direct interfaces allow experiments to bypass the CD when interacting with
    the CN.
  - Control software
    - Uses LXC tools on containers to enforce resource limitation, resource
      isolation and node stability.
    - Uses traffic control, filtering and anonymization to ensure network
      stability, isolation and privacy.
- The recovery device can force a hardware reboot of the RD from several
  triggers and help with upgrade and recovery.

** Node and sliver connectivity
# Node simplified diagram, hover to interesting parts.
Slivers can be configured with different types of network interfaces depending
on what connectivity researchers need for experiments:
- Home computer behind a NAT router: a private interface with traffic
  forwarded using NAT to the CN and filtered to ensure network stability.
- Publicly open service: a public interface (with a public CN address) with
  traffic routed directly to the CN and filtered to ensure network stability.
- Traffic capture: a passive interface using a direct interface for capture.
  Incoming traffic is filtered and anonymized to ensure network privacy.

- Routing: an isolated interface using a VLAN on top of a direct interface.
  It only can reach other slivers of the same slice with isolated interfaces
  on the same link.  All traffic is allowed.
- Low-level testing: the sliver is given raw access to the interface.  For
  privacy, isolation and stability reasons this should only be allowed in
  exceptional occasions.

* How the testbed works
# Event diagram, hover over components explained.
An example experiment: two slivers, one of them (source sliver) pings the
other one (target sliver).

1. The researcher first contacts the server and creates a slice description

    - Provides a familiar and flexible env for researchers.
  - Direct interfaces allow experiments to bypass the CD when interacting with
    the CN.
  - Control software
    - Uses LXC tools on containers to enforce resource limitation, resource
      isolation and node stability.
    - Uses traffic control, filtering and anonymization to ensure network
      stability, isolation and privacy (partialy implemented).
- The recovery device can force a hardware reboot of the RD from several
  triggers and help with upgrade and recovery (not implemented yet).

** Node and sliver connectivity
# Node simplified diagram, hover to interesting parts.
Slivers can be configured with different types of network interfaces depending
on what connectivity researchers need for experiments:
- Home computer behind a NAT router: a private interface with traffic
  forwarded using NAT to the CN and filtered to ensure network stability.
- Publicly open service: a public interface (with a public CN address) with
  traffic routed directly to the CN and filtered to ensure network stability.
- Traffic capture (not implemented yet): a passive interface using a direct
  interface for capture.  Incoming traffic is filtered and anonymized to
  ensure network privacy.
- Routing: an isolated interface using a VLAN on top of a direct interface.
  It only can reach other slivers of the same slice with isolated interfaces
  on the same link.  All traffic is allowed.
- Low-level testing (not implemented yet).: the sliver is given raw access to
  the interface.  For privacy, isolation and stability reasons this should
  only be allowed in exceptional occasions.

* How the testbed works
# Event diagram, hover over components explained.
An example experiment: two slivers, one of them (source sliver) pings the
other one (target sliver).

1. The researcher first contacts the server and creates a slice description