1. An Architecture for a Diversified Internet
Jon Turner
For some time, the networking research community has been concerned with our growing inability to effect change in the protocols and services that lie at the heart of the Internet. As the Internet has grown, it has become increasingly difficult to deploy needed improvements, leading to a growing ossification.
Our group has been investigating a new architectural approach to networking that would drastically reduce the barriers to deployment of improvements to the Internet. We call the resulting system a diversified Internet, because it allows diverse end-to-end networks to co-exist alongside one another.

2. Diversifying the Net Virtualization for ongoing progress in networking
enable new networking paradigms anytime, anyplace
Diverse metanetworks sharing common substrate
enable new architectures to be deployed and used
support wide range of protocols and service models
avoid architectural constraints on metanets
Substrate provides resource provisioning
substrate platforms host multiple metarouters
connect metarouters via metalinks
substrate supports dynamic configuration of metanets
long-term for metarouters and backbone metalinks
short-term for access metalinks
must accommodate distributed management of the substrate multiple service providers
Our architecture for a diversified Internet uses a form of network virtualization to allow multiple diverse networks to co-exist within a common infrastructure. The objective is to allow new networking paradigms to be developed and deployed at any time and any place. I am not going to spend much time on the arguments for a diversified Internet today, but instead am going to focus on how such a diversified Internet might be built.
First some terminology. We use the term metanetwork to refer to an end-to-end packet delivery system, which is built on top of a common substrate. Metanetworks can implement a wide variety of architectures and service models. And one of our key objectives in designing the system is to allow maximum flexibility for metanets.
The role of the shared substrate is to provide resources to metanetworks. This includes substrate platforms which host multiple metanetwork routers physical links which are are shared to provide metalinks, joining metarouters. The substrate must provide control mechanisms to allow metanets to be dynamically configured as they are needed. And the substrate must accommodate distributed management by multiple substrate providers.

3. Elements of a Diversified Internet
substrate link
metalink
substrate platform
meta router
Here’s a picture that illustrates this terminology. The diversified internet substrate consists of nodes and links. We refer to the nodes as substrate platforms and the links as metalinks. The substrate platforms host metarouters and the substrate links host metalinks. The substrate can host multiple metanetworks, and the end systems can communicate over multiple metanetworks, depending on their specific requirements.
substrate links may run over Ethernet, IP, MPLS, . . .
metanet protocol stack

4. Multiple Substrate Domains
Multiple owners
Metanets span multiple domains

5. Substrate Platform Architecture
Processing Engines (PEs) implement metarouters
variety of types
Line Cards terminate ext. links, mux/dmx metalinks
Shared PEs include substrate component
Dedicated PEs need not include substrate
use switch and Line Cards for protection and isolation
PEs in larger metarouters linked by metaswitch
Larger metarouters may own Line Cards
allows metanet to define transmission format/framing
configured by lower-level transport network
Line Cards
PEs
Switch

6. Current Development System
Network Processor blades
dual IXP 2850 NPs
3xRDRAM, 3xSRAM, TCAM
dual 10GE interfaces
10x1GE IO interfaces
General purpose blades
dual Xeons, 4xGigE, disk
10 Gb/s Ethernet switch
VLANs for traffic isolation

7. Architectural Neutrality
Allow maximum diversity among metanets
support variety of protocols, service models
Minimize substrate role, maximize metanet role
substrate will be difficult to change
metanets should handle all things that may change
Security and mobility
enable secure metanets
enable metanets that support mobility
minimize substrate role in providing security, mobility to enable on-going improvements
Limit substrate to resource provisioning role
provide “raw” resources to metanets
diversity of resource types
support addition of new resource types

8. Metanet Configuration
alternate access metalink routes
substrate domains
Metanet backbone provisioning
substrates advertise resource availability, cost information
metanet planner requests bids for metanet segments
iterate, as needed
Access metalink configuration
users may request connection from anywhere, at anytime
metanet determines termination point, domain-level route
substrate domains determine route segments

9. Substrate Control Communication
Metanet Controller (MC)
Substrate Domain Controller (SDC)
Substrate Control Metanet (SCM)
SCM for control communication outside metanets
may have more than one for reliability, upgradability
SDCs provide control interface to substrate domains
MCs provide control interface to metanets

10. Configuring Metanets Adding metarouter and metalinks2 1 3
Adding metarouter and metalinks
MC requests new metarouter & intra-domain metalink
configures metarouter within metanet
MC requests inter-domain metalink
peering domains coordinate metalink configuration

11. Configuring Access Metalinks3 4 2 1
When host connects to network
discover local substrate platform (using broadcast)
send metanet connect request to local SDC
request forwarded through SCM to MC for desired metanet
MC requests metalink configuration from SDCs
SDCs configure access metalink

12. Substrate Advertisements
Substrates advertise so metanets can use them
hosting capabilities advertisements
in region R, type T substrate platforms are available
multi-scale region specifications
peering advertisements
D1 peers with D2 in region R, with capacity C
latency advertisements
latency from R1 to R2 within substrate is D

13. advertised peering relationship
Metalink Routing
advertised peering relationship
Metanet uses peering adverts to identify paths
geographic information used to estimate distances
vertices of path are region center points
for substrates that supply internal region graph, use distances implied by region graph
Metanet requests route segments from substrates
request to domain D: metalink L, from D1 in R1 to D2 in R2
request may include a provisioned capacity
adjacent substrate domains use metalink identifier (L) to coordinate across domain boundary

14. Metanet Backbone Configuration
Inputs to metanet planner
substrate domain adverts
expected users/traffic
Planner
selects regions for metarouters
typically driven by users in region
may also include transit metrouters
selects metanet topology
determination of metalink capacities
peering points for inter-domain metalinks
determines metarouter configurations
number and capacity of interfaces
number and type of PEs
Metanet negotiates with substrate domains

15. Security Issues Enable secure metanets; minimize substrate role
enable continuing evolution of security mechanisms
Diversity of trust
most substrate domains cannot be trusted and should not be burdened with onerous security requirements
domains that host metarouters must be trustworthy
some metanets (e.g. SCM) must be trustworthy
Accreditation of selected substrates and metanets
accreditation is optional
carries with it certain responsibilities (maybe legal)
requires authentication, secure interaction
central authority with delegation evolving to multiple top-level authorities

16. Securing Metanets Use accredited substrate domains for metarouters
access metalink single endpoint spoof-prevention
accredited substrate domain
unaccredited substrate domain
Use accredited substrate domains for metarouters
Protect backbone metalinks using encryption
prevents eavesdropping, traffic insertion
can detect lost packets and hold substrate accountable
Protect access metalinks from misuse
prevent address spoofing by allowing only one endpoint
cryptographic authentication and data encryption

17. Addressing Each metanet may define its own addressing
hierarchical, geographical, flat, whatever
No common addressing needed for substrates
each domain can define and assign addresses independently of every other domain
metanet-to-substrate interaction does not require use of substrate addresses
metarouter locations specified by geographic regions
metarouters identified by a label and metarouter interfaces by local interface number
substrate-to-substrate interaction does require common label to identify peering substrate links
use label {domain1:address1,domain2:address2}

18. SCM Network Services MC
metanet
region 1 ad distribution tree
region 2 ad distribution tree
SCM
Unicast, best-effort datagram with receiver control
Advertisement distribution service
used by substrates and metanets to advertise services
senders may restrict delivery to region, recipient type
receivers may subscribe by advert type, domain, metanet
metarouters store adverts and respond to queries

19. Summary Virtualization for ongoing progress in networking
enable new networking paradigms anytime, anyplace
Architectural neutrality is key design principle
allow maximum diversity among metanets
minimize substrate role, maximize metanet role to enable ongoing change of the interesting stuff
special challenges for security and mobility
Defining control interactions
how substrates and metanets interact through SCM
how neighboring substrate domains coordinate for metalink configuration
how endpoints connect (and reconnect) to metanets
Many open issues
specifying metanet configuration, advance reservations,...

20. Roles of the Players Metanetworks Substrate providers
provide end-to-end packet delivery services to end-users and application providers
use services of multiple substrate domains
Substrate providers
provide infrastructure for use by metanetworks
provide access for application providers and end-users
Application providers
use metanets to reach end-users
can choose metanets that best serve their needs
End users
free to operate over multiple metanetworks
may choose metanets for services, available applications or cost