1. An XML-based System Architecture for IXA/IA Intercommunication
Peter D. Ungsunan
Tsinghua University

2. Background
Greater availability of network processors allowing us to use larger groups of processors
Distributed and heterogeneous systems
Use of XML to share data in applications
Increased use of open source software for portability and flexibility

3. Overview Creating an XML framework
to facilitate implementation of distributed network mechanisms
Across platforms
Using open standards and software
To allow higher level applications to easily interact with networking functions

4. Goals
Create a middleware framework for an IXA/IA media distribution application and for future distributed networking applications
Facilitate testing and implementation of distributed network applications and mechanisms
Support both IA and IXA architectures

5. System Architecture Has the following components Hardware Software
Protocol
Algorithms/Mechanisms

6. Hardware Management LAN Segment
Suitable for multi-homed network processors
We assume that the management segment will be secured
Isolated management segment as an out-of-band control channel
Secure
Redundant

7. Out-of-band Management LAN

8. Software Architecture
Linux OS (ie. Montavista, Red Hat 9)
Standard C libraries (ie. pthread, sockets)
Application Components
Application Code
Intel IXA SDK
XML Encoder
XML Parser (ie. Expat)

9. Software Architecture
Communication between IA server and IXP2350:
IA media server monitors CPU load, application state, etc., periodically, and sends an XML message to IXP2350’s server port
IXP2350’s server thread receives message, parses and updates the global variables for the application to access

10. Software Architecture
Communication between IXP2350s:
To send a message, the application on IXP2350 calls an API call that encodes the message into XML and sends the XML to the destination server thread. This is parsed and processed at the remote server thread.

11. Protocols XML/ NETCONF-like Over TCP/IP Sockets Configuration Data
Control commands
Over TCP/IP Sockets
TCP connection oriented
For large message size, and reliable transport
Slower than UDP
Unencrypted

12. Related Work NETCONF IETF Working Group XML based
Configuration Data
For initial configuration and updates
Protocol Messages
XML based
Hierarchal
Cross-platform
Several Encapsulations
IETF Draft Work in Progress

13. Application Mechanisms
Load Distribution
Feedback Mechanism
CPU Load
Failover

14. Load Distribution
Programs on IA media servers send information updates in XML to server thread on IXP2350
Server thread parses the XML and updates the applications’ global state variables for use by the main application

15. Failover Algorithm At Primary IXP2350
Start up and load configuration locally
Connect and synchronize configuration with secondary IXP2350
While running {
Send updates/keepalives to secondary }
Upon failure, send cutover command to secondary

16. Failover Algorithm At Secondary IXP2350
Start up and load local Configuration
Load Configuration from Primary IXP2350
Start server thread and listen for updates from IXP2350
If cutover command received or failure detected, then notify application to become active

17. Conclusion
Combination of open XML technologies can be used to enhance IA/IXA intercommunication
By combining these technologies, we can create more powerful network applications
Middleware can help applications on the IA platform influence networking functions on the IXA platform
Network Processors make a good testbed for emerging protocols such as NETCONF and testing complex mechanisms

18. Thank you Questions? Suggestions?