Reconciling Zeroconf with Efficiency in Enterprises

1
Reconciling Zero-conf with Efficiency in
Enterprises
Changhoon Kim and Jennifer RexfordPrinceton
University
1. State of the Art and Motivation

• Neither IP routing nor Ethernet bridging suffices

• Enterprise networks comprised of Ethernet-based
  IP subnets interconnected by routers

• Recent challenges
• Very large and highly populated Ethernet segments
  (e.g., campus-wide WLAN)
• Wide deployment of light bridges (e.g., wireless
  APs)
• Sometimes incapable of bridging, STP, VLAN, etc.
• Increasing demand of mobility
• Increasing complexity and inefficiency of IP
  address management (even with DHCP)
• Need for MAC-based access control

IEEE 802.1D Ethernet Bridging - Flat addressing
- Self-learning - Flooding - STP
C
A
IP Routing - Hierarchical addressing - Shortest
path routing - Subnet configuration - Host
configuration
E
B
D
Cant we just take best parts of each?
2. Solution SEIZE (Scalable and Efficient
Zero-config Enterprise)

• Addressing and packet format IEEE 802 Ethernet
• Mobility and minimal configuration via flat
  addressing
• Backward compatibility (including VLAN support)
• IP address provides external connectivity
  andapplication compatibility
• Core connectivity dissemination Link-state
  protocol
• Efficient resource utilization via pair-wise
  shortest paths and load distribution
• Scalability
• Fast convergence
• End-host information dissemination Consistent
  hash
• Scalability and stability via on-demand binding
  of host address and location
• Resistant to high churn rate
• O (1) look-up via link-state core

2.5 Delivery to x
3.2 Optimized tunneling directly from E
to A
y
x
C
1.1 Host discovery or active registration
2.1 Traffic to x
A
2.4 Tunneling to egress node, A
2.3 Hash-based routing to the relay node,
B
1.2 Hashing (H(x) B)
2.2 Hashing (H(x) B)
E
Link-statecore
Entire enterprise - A large single IP subnet
(e.g., 10.1.0.0/16)
3.1 Notifying ltx, Agt to E
B
1.3 Storing ltx, Agt at B
Network Node (MAC addr. A)
D
10.1.1.62
A
End-host (MAC addr. x)
q
x
p
Control flow
10.1.2.17
Unique and location-independent IP addressesthat
do NOT belong toa specific subnet
Data flow
10.1.3.45
3. Design Options
5. Prototyping and Evaluation

• Packet delivery mode
• Relayed or Direct
• Packet delivery mechanics
• Tunneling or Label swapping
• Label swapping borrows src MAC field to contain
  dst MAC
• End-host discovery
• Discover-from-data or Active registration
• ARP and DHCP
• Broadcasting or CHash-based proxy resolution
• Overloading DHCP for host discovery
• Intelligent broadcasting
• A sequence of unicasts along spanning tree

• Native Prototype
• Control plane
• XORP OSPF daemon
• Data plane
• Click EtherSwitch elementswith some SEIZE
  extensions

• Overlay Prototype
• Wide-area virtual enterprises
• SIAS (SEIZE-In-A-Slice)
• Another VINI instance
• Data plane
• IP-encapsulated Ethernet frames
• Click EtherSwitch and IPRouter elements with
  SEIZE extensions

• Evaluation
• Modeling and analyzing host informationcaching
  behavior
• Simulation with ns-click
• Emulation on Emulab or PlanetLab
• Intra-enterprise/campus traffic dumps (just
  headers)are welcome!

4. Further Applications

• Load sensitive routing
• E.g., Selective application of VLB (Valiant Load
  Balancing)
• Service mobility
• Relay node masks hand off
• Src MAC-based reachability control
• Path obfuscation or anonymization
• Topology does not reveal actual data paths