Position: IMS Architect
Term: Full time (US Citizen, Green Card or H1)
Location: Frisco, TX
Genband experience is highly preferred.
Position will primarily be a SME (Subject Matter Expert) on all IMS/VoLTE network and system core elements such P/I/S-CSCF based on Nokia Siemens IMS core.
The person will work to support the deployment and operations related to IMS/VoLTE services involving of both signalling and user plane traffic.
This position needs good knowledge of operating systems, integration and testing support, SIP and Diameter protocols and cross functional work experience to facilitate support of multiple IMS cores.
- Performs daily operations and technical support in the IMS domain and work with different internal teams and external vendors on interoperability testing with VoLTE/IMS equipments such as CSCF, HSS, OneNDS, AAA in the deployment and production network.
- Level 3 and 4 support on troubleshooting network issues related to IMS signaling and user plane traffic.
- Develop tools to automate the deployment and operations processes, predict IMS network weakness and potential issues.
- Conduct and analyzed VOLTE captures using Tektronix IRIS ISA tools. Analyzed call failures in the networks and issues RCA/RCF.
- Analysis of VOLTE calls to include call waiting, call barring, call conferencing and etc.
- Use Netscout IRIS ISA, IPI, IPA, and ITA to debug VOLTE issues.
- VOLTE IMS Registration Process
- Debug SIP registration authentication protocol and flows
- IPSEC Security Associations Establishments
- P-CSCF discovery
- DNS Query
- PCSCF, ICSCF, SCSCF, BGW, PCRF, TAS, SAE-GW, ENUM Server
- Debug EAP, Diameter, and SIP call flow.
- Debug different SIP errors codes: 100,200, 300, 400 and 500.
- RAND, AUTN,XRES, RES, K
- Debug LTE call flow issues in relations to setting VOLTE call.
- VOLTE Call Setup Process
- Debug Call Failure for Onet and Offnet call.
- Debug VOLTE for Call muting, call drop, and different multiples error codes.
- Debug VOLTE Calls for offnet call interaction with MGW PCAP messages.
- Debug RCS call flow and MMS message
- Understand and interpret 3GPP protocol and SIP RFC.
- Subject Matter Expert in SIP protocol and SIP Call flow
- Strong analytical and problem solving skills
- Experience in LTE, Wireless Mobility Network Domain and IMS Architecture.
- Good Network topology and various interfaces(S1,S6a, S11, SGI, CX, GM, RX, SY, GX, GY and etc)
- Protocol Literacy: SIP, Diameter, ENUM, DNS, SS7, ISDN, MAP, IS41, TCAP, ISUP, INAP, ISUP, BICC, SCCP, H.248, GTP, IBCF, Softswitch and PSTN gateway, MMTel, RCS.
- Experience in sizing, dimensioning and scaling of network elements like CSCF (P/I/S/E), IMS HSS, BGCF, MGCF, SGW, MGW, SBC, MRF, TAS, Messaging, Conferencing, SNG, MNP servers etc.
- Good understanding of operating principles for IMS client and codecs.
- Working knowledge of telecom networks like 2G, 2.5G, 3G and LTE (MME, SGW, PGW, and MME).
- Working knowledge of VoWifi to VOLTE hand-over and vice versa.
- Ability to work in a high-pressure dynamic environment and adjust to priority changes
- Good verbal and written communications skills
- Good understanding of call processing between end to end system
- Good understanding of CS fall back and MOCN.
- Good understanding of Nokia CFX-500
- Diagnosing and fixing errors in network and core system