1. 1 Notice (c) ZTE CORPORATION. ZTE Corporation, grants a free, irrevocable license to 3GPP2 and its Organizational Partners to incorporate text or other copyrightable material contained in the contribution and any modifications thereof in the creation of 3GPP2 publications; to copyright and sell in Organizational Partner's name any Organizational Partner's standards publication even though it may include all or portions of this contribution; and at the Organizational Partner's sole discretion to permit others to reproduce in whole or in part such contribution or the resulting Organizational Partner's standards publication. ZTE Corporation is also willing to grant licenses under such contributor copyrights to third parties on reasonable, non-discriminatory terms and conditions for purpose of practicing an Organizational Partner’s standard which incorporates this contribution. This document has been prepared by ZTE Corporation, to assist the development of specifications by 3GPP2. It is proposed to the Committee as a basis for discussion and is not to be construed as a binding proposal on ZTE Corporation. ZTE Corporation, specifically reserves the right to amend or modify the material contained herein and to any intellectual property of ZTE Corporation other than provided in the copyright statement Wei Wang wang.wei@zte.com.cn wang.wei@zte.com.cn Xiaowu (Frankle) Zhao zhao.xiaowu@zte.com.cn May, 2009 zhao.xiaowu@zte.com.cn Issues on the Reset procedure

2. 2 Reset from the MSCe - problem   A30-20090511-006 says “…, the SNSF shall discard any Reset messages received from an MSCe.”   [ZTE]: If the Reset message is discarded by the SNSF, as a result, the MSCe will never receive any Reset Ack message. However, according to the A.S0014-D, if the MSCe does not receive a Reset Ack message, it will keep resending the Reset message to that BSC. In other words, if the MSCe fails to receive a Reset Ack message, it can not determine whether the BSC can handle calls or not. "If the MSC sends a Reset message to the BS and does not receive a Reset Acknowledgement message before timer T16 expires then it shall repeat the reset procedure with respect to that BS."

3. 3 Reset from the MSCe – possible solutions   [Solution 1A]: Upon receiving a Reset message sent from an MSCe, the SNSF discards it and responds with a Reset Ack to the MSCe.   The BSC uses other methods to release the related resources, e.g. handshake mechanism.   [pro] The SNSF can be easily implemented.   [pro] Will not lead to undesired release of calls in other MSCes.   [pro] No need to modify current IOS standards   [con] The procedure to release resources will incur extra process delay.   [Solution 1B]: The SNSF discards the Reset message from an MSCe. When the MSCe does not receive an Reset Ack message, it resends the Reset message a configurable number of times.   If the Reset Ack is still not received after a configurable number of tries, the MSCe considers the BSC can handle calls now.   The BSC uses other methods to release the related resources, e.g. handshake mechanism.   [pro] The SNSF can be easily implemented.   [pro] Will not lead to undesired release of calls in other MSCes.   [con] Need to modify current IOS standards.   [con] The procedure to release resources will incur extra process delay.

4. 4 Reset from the MSCe – possible solutions   [Solution 1C]: For each call, The SNSF saves the mapping info between sua connection, BSC id and MSCe id. Upon receiving a Reset message sent from an MSCe, the SNSF lookups the mapping info and finds out those sua connections between the BSC and the SNSF which are related to this MSCe, then SNSF releases these sua connections.   [pro] Will not lead to undesired release of calls in other MSCes.   [pro] No need to modify current IOS standards.   [pro] No extra process delay introduced when releasing resources.   [con] The SNSF is stateful and a little complicated to be implemented.

5. 5 Reset from the BSC - question   A30-20090511-006 says “Regarding the Reset message sent by the BSC, the SNSF shall send the message to each MSCe in the PA; at each MSCe, the source BSC of the Reset message is identified by means of lower layer addressing information.”   [ZTE]: Per our understanding, the MSCe can not identify the BSC by means of lower layer addressing information. Could HW explain what lower layer addressing information refers here and give more details?

6. 6 Reset from the BSC – possible solutions   [Solution 2A]: Upon receiving a Reset message sent from a BSC, the SNSF discards it and responds with a Reset Ack to the BSC.   The MSC uses other methods to release the related resources, e.g. handshake mechanism.   [pro] The SNSF can be easily implemented.   [pro] No need to modify current IOS standards   [con] The procedure to release resources will incur extra process delay.   [Solution 2B]: For each call, The SNSF saves the mapping info between sua connection, BSC id and MSCe id. Upon receiving a Reset message sent from a BSC, the SNSF lookups the mapping info and finds out those sua connections between the SNSF and the MSCe which are related to this BSC, then SNSF releases these sua connections.   [pro] Will not lead to undesired release of calls in other MSCes.   [pro] No need to modify current IOS standards.   [pro] No extra process delay introduced when releasing resources.   [con] The SNSF is stateful and a little complicated to be implemented.

7. 7 Summary and Recommendations   It is recommended to use Solution 1C and Solution 2B to handle the two scenarios of reset procedure respectively. Thus no particular text is required to describe the Reset message routing behavior.   If simplicity is the top concern, ZTE suggests using the following text when describing the Reset message routing behavior at the SNSF. “In the specific case of the Reset message, when receiving a Reset message from an MSCe, the SNSF shall discard the message and responds with a Reset Ack to the MSCe (if the SNSF is not collocated in the BSC), or shall pass the message to the BSC via internal interfaces (if the SNSF is collocated in the BSC). Regarding the Reset message sent by the BSC, the SNSF shall send the message to each MSCe in the PA.”

8. 8 Thank You