CBN Work in Progress

NOTES:

QUESTIONS:

1. Confirm Context based backhaul routing is only for data applications (including VoIP) but does not deal with pure voice i.e., 1xRTT
2. Confirm that the current deployment of data network in sprint is 1xEV-DO rev 0.
3. Is sprint planning on deploying EV-DO rev A anytime soon, or by the time this project is implemented?
4. What is the physical equipment in the BTS? What is the logical diagram inside the BTS? How is the pure voice dealt with as opposed to data traffic in the BTS?
5. Can sprint provide us with CDMA university documents on Air interface (ABIS) for EV-DO. Any other documents will help too.
6. Is the sprint network based on Lucent equipment or Nortel equipment. Some good strategies are published in Bell Labs Technical Journal specific to Lucent based solutions.
7. Is sprint interested in doing selective routing per connection, session, or packet?
8. Is every AT/cellphone assigned a public IP address per connection ? per application ? per day?

Potential Solutions:

1. The service class of the application is represented in one of the bits in the CDMA 2000 air interface packet. This has to be done by a cross-layer mechanism. The BTS analyzes the CDMA packet header to derive the service class of the packet. The CDMA packets are then transmitted over the suitable link.
2. The service class of the application is represented in the TOS field of the IP header at the AT. The BTS has the capability to reconstruct the complete IP packet out of the CDMA packets recieved. In other words, BTS has features similar to the RNC except for the hand-off capability. Once the service class is derived, the IP packets are reconverted in to CDMA fragments.
   1. The advantage of this approach is that the same components used at RNC can be used at BTS
   2. The disadvantage is the additional defragmentation and fragmentation.
3. The service class of the application is represented in the TOS field of the IP header at the AT. BTS does not perform per packet analysis. Instead, the RNC/PDSN derivse the service class of the session (possibly per packet) from the IP packet which is readily available at the PDSN and signals the BTS on the link to be used for the remainder of the session.
   1. The advantage of this approach is that not much changes are required at the BTS
   2. The disadvantage is that the various traffic types with in a given session cannot be differentiated very easily. However, if the RNC can signal BTS to change the links during a session, then this can also be achieved.