request routing requirements

["Abbie Barbir" <abbieb@nortelnetworks.com>]

Here are some of the high level requirements for the request routing system.
Details will be discussed later.

Abbie Barbir and Nalin Mistry (nalin@nortelnetworks.com)

1. CDNs should be treated as "black-box" networks

2. Types of request-routing
  - DNS based (short term main focus)
  - Layer-7 / Proxy based
 - Need a reference architecture of the major senarios
 - Need support for static and dynamic routing interface

3. Specific Protocol Requirements for Request-Routing Systems
   These features should be in the protocol:
 - Connection oriented and secure
 - Scalable
 - ability to exchange full or incremental updates
 - Support capability negotiation including:
   - granuality of advertisement
   - flooding frequency

 - Prevent looping of information
 - Support of required and optional metrics
 - Support advertisements
 - Protocol should be able to force update
 - Protocol should be able to perform peer discovery
 - Protocol should be able to perform Recovery (content based and routing
based)
 - Protocol should support the seperation between the route plane and the
forwarding plane


3.1 Information that must be exchanged as part of the Request-Routing
systems Protocol
 - Supported content type
   - HTTP, streaming, etc.
 - Metrics associated with a content type
   - Available aggregate B/W
   - Distribution Model (PUSH, PULL, On Demand)
 - CDN footprint
 - Supported request-routing types (static, dynamic, DNS or L7)

4. Request-routing types (more details on mechanism)

 - DNS based types must support the following
   - Redirection based on CNAME records
   - Ability to identify owner (origin or CDN) of content based on URI
     - Need to agree on a content naming convention

 - Need to investigate further L7 requirements

4.1 Data encoding should provide flexibility to support extensions in the
future

5. Interface to Distribution system
   - Interface to the Content Provider ?

6. Interface to Accounting system