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Introduction to Mobile Core Network
- 1. Introduction into MobileCore Network WebEx Sunday Session 24 March 2013
- 2. About this presentation • Goal – Introduction into 2G/3G and 4G core network element in Telco technology, particular for non-Telco person. – Overview of call establishment process – Experience sharing of 4G EPC project delivery from existing Mobile Network Operator. • What is not covered here… – Wireless and radio related part. – Detail and ‘deep dive’ of each network element. – Detail procedure for call establishment. • Disclaimer – All material presented here is solely for non-profit educational purpose.
- 3. Node and Interfacein Telco • What is a Node ? Node is a network component that is capable of receiving, sending or forwarding electronic information over the designated communication link. For example BSC, RNC, SGSN, MSC, HLR. Known as Network Element too.. • What is an Interface ? In telecommunication, an interface is a logical link connection or a reference point, between two components in telecommunication infrastructure, for example, Gn interface is a reference point between SGSN and a GGSN. However, Telecommunication also use term ‘interface’ as a device or program of that enabling a communication between user and a computing device.
- 4. 2G and 3GNetwork Architecture Circuit Core Domain Nc MSS/VLR MSS/VLR MS BTS Mc Mc Nb MGW MGW PSTN Abis Other PLMN BSC A SMSC RADIUS Charging Centre IuCS HLR DNS NMS / OSS PCRF DHCP RNC Gb Service & subscriber management MS Iub IuPS Gz/Gs/Gr/Gf/Gd Packet Data Network Gx/Gz e..g Internet NodeB Gi Gn SGSN GGSN Packet Core Domain Control plane User plane
- 5. Acronym used inTelco.. MS Mobile Subscriber A mobile phone with SIM card BTS Base Transceiver Station Air interface toward MS in 2G BSC Base Station Controller Controlling BTS NodeB n/a Air interface toward MS in 3G RNC Radio Network Controller Controlling NodeB MSS Mobile Switching Server Mobility Management for CS Domain VLR Visitor Location Register Manage temporary subscriber information within an MSS HLR Home Location Register Manage permanent subscriber Database MGW Media Gateway Manage user plane traffic SGSN Support GPRS Service Node Mobility Management for PS Domain GGSN Gateway GPRS Service Node Session Management , IP address allocation, QoS enforcement, Routing toward internet.
- 6. Circuit Switching vs.Packet Switching • Circuit Switching –Mostly used in the voice call. –Whenever a call is being made, a dedicated logical link needs to be established. –Network resource is allocated and reserved for the subscriber for entire duration of the call. • Packet Switching –Mostly used in the Packet Data Connection.. . e.g. internet browsing –Whenever an MS sends or receives data, data is organized into packet and each packet has source / destination ID.
- 7. Signaling Plane vs.User Plane • User Plane is the user traffic that contain the conversation between 2 or more user peers. – Carried over the core network as a bearer – Example. Voice call or Browsing data traffic through GPRS • Control Plane is signaling communication used to control the bearer traffic. – Involving of sending and receiving messages between 2 nodes. – Example. Communication between SGSN and HLR.
- 8. A Simplified 2G/3GPS Call Flow…(1/3) Reference : TS 23.060 1 Attach request.. Herewith the info TS 24.008 3 TS 29.060 HLR Gn DNS MS BTS / Nodeb Abis / Iub I am attached 5 Get info for this Packet Data Network to the network BSC 2 subscriber e..g Internet and want to RNC browse, by activating PDP Gb IuPS Gn context SGSN GGSN Attach 4 Internet accepted.. DNS Note : All procedures here are simplified for overview only. Reader should refer to above reference for detail procedures.
- 9. A Simplified 2G/3GPS Call Flow…(2/3) Reference : Herewith the IP address TS 23.060 of GGSN 7 TS 24.008 TS 29.060 HLR Gn DNS MS BTS / Nodeb Abis - Iub I am attached 5 Gb -IuPS Packet Data Network to the network BSC e..g Internet and want to RNC browse , by activating PDP Gn context SGSN GGSN Gi 9 Internet 8 11 6 Create PDP Context DNS PDP context activation received Create PDP accepted from MS, Context PDP context activation What is the IP address of the Request accepted, now browse to GGSN that serving this APN ? ? www.google.com.au 10 Create PDP context accepted, send this Note : info to MS All procedures here are simplified for overview only. Reader should refer to above reference for detail procedures.
- 10. A Simplified 2G/3GPS Call Flow…(3/3) Reference : TS 23.060 TS 24.008 TS 29.060 HLR Gn DNS MS BTS / Nodeb Abis - Iub 12 Gb -IuPS Packet Data Network BSC e..g Internet 11 RNC Gn PDP context activation SGSN GGSN Gi accepted, now browse to www.google.com.au 13 Internet DNS Note : All procedures here are simplified for overview only. Reader should refer to above reference for detail procedures.
- 11. Handover Action of switching a call in progress from one radio channel to another to secure the continuity of an established call. The purpose of handover control is to manage the mobility aspect of the Subscriber. This means keeping track of mobile stations (MS) as they move around in the network, and ensuring that their connections are uninterrupted and meet the negotiated Quality of Service requirements.
- 12. Move to 4G..??? •Wait…first, let see the widely involvement of IP protocol. • Protocol used in the control plane messaging has evolved. – Changes in Transport Layer protocol while keeping all the Application Layer remain unchanged. – Completely changed at Transport and Application Layer. • Transport Layer has changed dramatically from legacy protocol toward IP.
- 13. General LTE Architecture BTS/NodeB SGSN BSC/RNC Pre R8 Gb PCRF 2G/3G Iu R7 DT Gn Gn BTS BSC 2G SGSN Gx R8 2G Gb SGi Internet SGi Operator services S5 S12 DT SGW PGW S4 NodeB RNC R8 3G SGi Iu S11 HSS SGSN S1-U S3 S6a eNodeB LTE S1-MME MSC SGs MME S10 Control plane Basic EPS architecture defined in 3GPP TS 23.401 User plane
- 14. Acronym used in4G E-NodeB Air interface toward MS in 4G MME Mobility Management Entity Mobility Management for 4G, Control Plane only S-GW Serving Gateway Mobility Management for 4G for User Plane, Handover anchoring . P-GW Packet Data Network Gateway Routing to Packet Data Network, Session Management, IP address Allocation. Function of P-GW is similar to GGSN in the 2G/3G network HSS Home Subscriber Server Manage Permanent 4G subscriber data. Evolution of HLR.
- 15. Internet has drivenoperation model…(1/3) Operator Network TDM HLR SGSN IP / MPLS GGSN Internet ATM RNC Multiple network type exist on Mobile Operator Network
- 16. Internet has drivenoperation model…(2/3) Operator Network TDM HLR SGSN IP / MPLS GGSN Internet ATM RNC Driven by internet grows, Telco vendor is developing their product using IP as the transport media.
- 17. Internet has drivenoperation model…(3/3) Operator Network HLR SGSN IP / MPLS GGSN Internet RNC Driven by internet grows, Telco vendor is developing their product using IP as the transport media. Mobile Operator needs to ‘simplify’ the O&M for many network type. New challenges and opportunities are on-board for IP (IT) and Telco engineer.
- 18. Protocol has beenchanged.. (1/2) INAP/CAP MAP BSSAP ISUP TUP TCAP SCCP M3UA SCTP MTP Layer 3 IP MTP Layer 2 Data Link Layer MTP Layer 1 Physical Layer Legacy Gr Interface Gr Interface Between SGSN – HLR Between SGSN – HLR Using MAP Application Using MAP Application SS7 protocol SS7 protocol transported over IP
- 19. Protocol has beenchanged… (2/2) Diameter Application M3UA SCTP SCTP IP IP Data Link Layer Data Link Layer Physical Layer Physical Layer Gr Interface Between SGSN – HLR S6a Interface Using MAP Application Between MME – HSS SS7 protocol transported Using Diameter Application over IP RFC 3588 TS 29.272
- 20. IP is here… UE eNB S-GW P-GW PDCP PDCP GTP-U GTP-U GTP-U/GRE GTP-U/GRE User Plane UDP UDP UDP UDP RLC RLC IP IP IP IP MAC MAC L2 L2 L2 L2 PHY PHY L1 L1 L1 L1 Uu S1-U S5/S8 UE eNB MME S-GW P-GW NAS NAS GTP-Cv2 Control Plane GTP-Cv2 GTP-Cv2 RRC RRC S1AP S1AP PMIP PMIP PDCP PDCP SCTP SCTP UDP UDP UDP RLC RLC IP IP IP IP IP MAC MAC L2 L2 L2 L2 L2 PHY PHY L1 L1 L1 L1 L1 Uu S1-MME S11 S5/S8
- 21. …and here… SGSN / MME MME SGSN S-GW Control Plane GTP-Cv2 GTP-Cv2 GTP-U GTP-U User Plane UDP UDP UDP UDP IP IP IP IP L2 L2 L2 L2 L1 L1 L1 L1 S3/S4/S10/S16 S4/S12 MME HSS/EIR Control Plane Diameter Diameter SCTP/TCP SCTP/TCP IP IP Reference : L2 L2 TS 29.281 L1 L1 TS 23.401 S6a/S6d/S13
- 22. …and everywhere… Example :VRF Concept VRF A •IP addressing scheme ? Private/public ? VRF B •Running OSPF between Node and PE VRF C •Area 0 or non-backbone ? VRF D •Stub or totally stub ? NSSA ? •or should BGP being used ?? P-GW PE VRF S5 VRF S1u VRF OAM VRF SGi A wake up call for Telco Engineer !!! Multiple OSPF process
- 23. Multihoming Concept ISP A Customer – Provider Costumer C ISP B …While in telecommunication has another view about multihoming.. Client Role Server Role 192.168.1.1/24 Primary Path 192.168.3.1/24 192.168.2.1/24 Secondary Path 192.168.4.1/24 • Based on IETF - RFC 4960 • Application always use 2 IPs from different subnet for each node. • Whenever there is a failure in primary path, the client and server automatically switch the traffic into secondary path. • Applied for most signaling traffic, such diameter, Sigtran. • Telco engineer to make sure that Client – Server communicate correctly. • IP engineer to make sure that there is a path diversity within IP network and there is NO unseen single point of failure may happen.
- 24. A Simplified PSCall Flow with 4G…(1/2) Herewith the IP Attach Herewith the Addresses 5 Reference : request.. info 3 1 TS 29.281 HSS DNS TS 23.401 MS eNodeB TS 29.274 Get info for this What is the S-GW IP Address ? 2 subscriber What is the P-GW IP Address ? 4 S1 Create Session Request with I am attached to MME IP Address of S-GW and P- the network and GW 6 S1u Packet Data Network want to browse to S11 www.google.com.au e..g Internet 11 Create Session Request response (Accept) 10 S-GW P-GW SGi S5/S8 8 Create Session Request with IP Address of P-GW 7 Create Session Request Create Session Request response (Accept) response (Accept) 9 Note : All procedures here are simplified for overview only. Reader should refer to above reference for detail procedures.
- 25. A Simplified PSCall Flow with 4G… (2/2) Reference : TS 29.281 HSS DNS TS 23.401 MS eNodeB TS 29.274 S1 I am attached to MME the network and Packet Data Network want to browse to S1u S11 e..g Internet www.google.com.au 11 12 S-GW P-GW SGi S5/S8 13 Internet DNS Note : All procedures here are simplified for overview only. Reader should refer to above reference for detail procedures.
- 26. LTE QoS ConceptOverview • Admission Control – Prioritize bearers based on QoS parameter – Protect network element in case of congestion or overload. • Traffic Control – Traffic classification (queuing, scheduling) – Traffic policing and shaping
- 27. EPC Project Delivery • Client : one of live mobile operator • Duration : Jan 2012- November 2012 • Involving 3 areas of expertise : – PS Core – CS Core – IP Prepare Optimization Plan Operate Design Implement
- 28. Network Assessment :Current 2G/3G Mobile Packet Core Project Delivery: EPC Node Commissioning and Integration Network Target : LTE & 2G/3G interworking BTS/NodeB SGSN BSC/RNC Gb Iu R7 DT Gn Gi Gn Pre R8 GGSN Gr 2G/3G HLR/HSS Internet SGW PGW Operator services S6a S5 SGi LTE S11 S1-U eNodeB S1-MME MSC SGs MME S10 Control plane User plane
- 29. Lessons learned andChallenges... • It is a new technology.. – New network elements, protocols and procedures. – Everyone involve may have their own interpretation during planning, commissioning and integration. – Limited reference from available production network. – Always refer to International Standard. 3GPP, RFC and GSMA. It is all IP.. – A complexity of client MPLS network. – Design and Planning is taking an important step. – Requires an intensive collaboration work with IP team. – Things worth to note… • L1 implementation. Wrong cable positioning • VLAN and IP addressing, public/private ?? • Pay attention into any node limitation : port type, MTU, active/standby behavior, Load Balance concept, Client-Server role
- 30. Diameter Routing Planning.. WithoutDRA DRA=Diameter Routing Agent With DRA HSS HSS HSS HSS EIR HSS EIR DRA DRA Roaming Partner /GRX MME MME MME MME
- 31. Some screenshots from4G handset Some speed test in various location.
- 32. Upcoming technical challengeswith LTE
- 33. More Information Technical Specificationand Standard. Readable and downloadable for public • www.3gpp.org/specification-numbering • www.ietf.org • http://www.gsma.com/newsroom/technical-documents EPC Product Knowledge. Also readable and downloadable for public • http://www.cisco.com/en/US/products/ps11072/products_installatio n_and_configuration_guides_list.html Further discussion • Parakontel • Indocisco
- 34. …ready to ‘take-off’now ? …then please fasten your seatbelt… Thank You….
- 35.