Dr. Muhanna, a Senior Consultant at Award Solutions, joined Award Solutions in March 2012, bringing his 15+ years of experience in wireline and wireless technologies in addition to internet and IP mobility, Packet Core System architecture and development, Interworking between different Wireless technologies and IP security.
During his work as Senior Designer and Technical Manager at Nortel, Dr. Muhanna was the design prime for the IOT activities that brought about the first successful end-to-end 1xRTT mobile IP call using QUALCOMM handset and Nortel wireless access and packet core nodes (PDSN and Home Agent). In addition, Dr. Muhanna led the successful delivery of many development projects on Nortel PDSN, Home Agent, and GGSN.
Since 2006 until joining Award Solutions, Dr. Muhanna has been actively participating in IETF, 3GPP2, and 3GPP standardizations in the areas of IP mobility, Packet Core Data System and Services, Interworking between different cellular technologies, cdma2000 RAN and IP Security. During his participation in IETF, 2006-2009, Dr. Muhanna produced many individual IETF drafts and was successful in authoring and co-authoring 4 IETF RFCs.
In addition, Dr. Muhanna has been the vice chair of 3GPP2 TSG-S WG4 [Security] and actively participated in the development of packet switching related cdma2000 Packet Data Services, IP mobility, RADIUS, Diameter, Policy Control, cdma2000 RAN, eHRPD/LTE IWK and security standards. He also authored many contributions on M2M services and architecture over IP-based access network, e.g., cdma2000 and LTE.
While representing Nortel at 3GPP SA3 WG [Security], 2007-2009, Dr. Muhanna worked with tier1 customers to bring contributions that address the security architecture for eHRPD-LTE IWK in TS33.402 including contributions on MIP4 and MIP6 security. In addition and while working at Nortel, Dr. Muhanna has been involved in the overall LTE EPS architecture design and discussion which included the support of Nortel 3GPP SA2, CT1, and CT4 delegates in writing contributions and areas of internet mobility and security
Currently at Award Solutions, Dr. Muhanna is working on the development and the delivery of training on IP Convergence that is related to 4G Backhaul and end-to-end IP Networking for LTE operators. In addition, Dr. Muhanna will be working on LTE-EPC focused training materials with future possible emphasis on M2M and Security
Dr. Muhanna holds a Ph.D. in Engineering from North Carolina State University, a Master of Science degree in Engineering from the University of Wisconsin in Madison, Wisconsin, and a Bachelor of Science degree in Engineering from Al-Mansoura University in Egypt.
As per LTE EPS architecture, SCTP is used as the transport protocol for S1 and X2 control interfaces, i.e., S1-MME and X2-Control, where S1AP and X2AP are being used, respectively. The details of SCTP usage over these two interfaces is captured in TS36.412. (S1AP, X2AP SCTP ports: 36412 & 36422, respectively)
According to TS36.412, there is a single SCTP association between the eNB and the MME and between any pair of eNBs whenever X2 is available. In addition, the specification mandates that a single stream be used for Non UE-Associated signaling, e.g. this stream is used for all eNB-MME signaling for carrying configuration parameters, load balancing information, etc., and one or more streams for UE-Associated signaling. One last mandate is that all “single UE signaling” shall be carried over the same stream. Moreover, the specification reference RFC4960 for the details of SCTP.
As per RFC4960, the two SCTP end points agree on the number of outbound and inbound streams during the initiation of the SCTP association using two 16-bits fields in the SCTP INIT and INIT ACK chunks, i.e., maximum number of outbound/inbound stream is 65,535.
Since one of the most fundamental advantages of SCTP over TCP is avoiding the head-of-line blocking by the use of multiple streams, the number of outbound and inbound streams become an important factor for each SCTP association. In other words, the eNB could theoretically have up to 65k+ streams but the more streams the SCTP association end-point has the higher the overhead for managing those streams.
If we would like to have a theoretical example of an SCTP association in E-UTRAN, e.g., over S1-MME from the eNB location, it would be normal to expect something as follows (see figure below):
Although, each chunk carries a sequence number that reflects the chunk sequence within its own stream, it also carries a Transmission Sequence Number (TSN, 32-bits) that reflects the chunk sequence with respect to all chunks that are transmitted over the SCTP association. One last observation, since DATA chunks is used to carry S1AP signaling, it is expected that each SCTP packet to have a single UE S1AP signaling message; thus a single DATA chunk per SCTP packet.