Topic 3 NGN Standards and Transition to NGN PDF

CHAPTER 3 NGN Standards and Transition to NGN 3.1 Understand Main Drivers to Next Generation Networks Introduction  According to the ITU’s definition of NGN, an NGN is a packet-based network able to provide telecommunication services to users and able to make use of multi...

CHAPTER 3 NGN Standards and Transition to NGN 3.1 Understand Main Drivers to Next Generation Networks Introduction  According to the ITU’s definition of NGN, an NGN is a packet-based network able to provide telecommunication services to users and able to make use of multiple broadband, QoS-enabled (quality of service) transport technologies and in which service- related functions are independent of the underlying transport-related technologies.  It enables unfettered access for users to networks and to competing service providers and services of their choice.  Drivers and motivation for NGN Deployment  External drivers and internal motivation put pressure on operator`s NGN deployments.  Figure 3.1: NGN Drivers As a summary, particular drivers for NGN (Figure 3.1) can be divided into several groups (but not limited only to them), such as: development of broadband Internet access including fixed broadband and mobile broadband, convergence of ICT markets to Internet, technological convergence to IP-based networks and services, requirements for end-to-end QoS provisioning in the Internet, as well as transition of PSTN, PLMN ,and TV broadcast networks to the Internet environment. (i) Explain Fixed Broadband Internet Access Definition:  refers to high-speed connectivity for public use of at least 256 Kbit/s or more in one or both directions (downloading and uploading).  It includes cable modem Internet connections, DSL Internet connections of at least 256 Kbit/s or higher, fibre and other fixed broadband technology connections (such as satellite broadband Internet, Ethernet LANs, fixed-wireless access, Wireless Local Area Network, WiMAX, etc.). Characteristic:  Fixed broadband access refers to copper and fiber.  Copper systems were based on twisted-pairs and copper cables.  Twisted pairs were used for decades in the access networks of the PSTN, and they evolved to Digital Subscriber Lines (DSLs) by adding additional equipment at the user premises and on the network’s side (ii) Explain Mobile Broadband Internet Access Definition:  Mobile broadband is a wireless technology that allows to connect a mobile device such as smartphone or tablet to a broadband internet connection wirelessly through a mobile phone network. Characteristic:  Mobile broadband has been established with the 3G technologies (e.g: UMTS/HSPA, Mobile WiMAX 1.0), and evolves further with rollout of mobile networks with already standardized 4G technologies (e.g: LTE-Advanced, Mobile WiMAX 2.0).  Users carry mobile devices all the time.  With broadband access to the Internet, mobile users with computationally capable mobile devices (e.g., smartphones) may use all services available in the Internet regardless of their location and the time. Why is broadband Internet access a driver to NGN? It is due to two main reasons: a. a. The Internet itself as an adopted networking platform for services worldwide b. b. Broadband Internet access (with higher bit rates) provides the possibility for all existing services to be provided via the Internet access, including television and other video services (e.g., video on demand, video streaming, etc.) as most demanding ones regarding the required bandwidths. 3.2 Remember Standardization Synergy of IETF, 3GPP and IEEE  Several other standardization organizations had important roles for NGN, either directly or indirectly.  Some of them are regional organizations such as ETSI (European Telecommunication Standardization Institute) in Europe, CJK (China Japan Korea) in Asia, while others are global standardization organizations such as ITU, IETF, 3GPP (3G Partnership Project), and IEEE.  The global leader in NGN standardization and its Figure 3.2: Activities toward NGN harmonization is the ITU (Figure standardization between different 3.2). standards bodies (i) Identify the following items: a. IETF Role Definition:  The IETF (Internet Engineering Task Force) is the body that defines standard Internet operating protocols such as TCP/IP.  The IETF is supervised by the Internet Society Internet Architecture Board (IAB ). Role:  Since NGN is based on all IP networks, it is using Internet Technologies which are standardized by IETF.  The most important is IP (IPV4 & IPV6), then transport layer protocols (OSI- Layer 4) such as TCP and UDP, and SCTP, then routing protocols and principles, VPN, applications, peer to peer applications, fundamental Internet technologies, security protocols and solutions, and many more which are incorporated into NGN recommendations in standardized contexts. (i) Identify the following items: b. ETSI Role Definition:  The European Telecommunications Standards Institute (ETSI) is an independent, not-for-profit, standardization organization in the telecommunications industry (equipment makers and network operators) in Europe. Role:  ETSI contributed to NGN standardization via its technical committee called TISPAN (Telecommunications and Internet converged Services and Protocols for Advanced Networking), created also in 2003.  Regarding the NGN standardization ETSI has closely collaborated with 3GPP (3GPP standardizes mobile technologies such as GSM in 2G, UMTS in 3G, and further evolution with LTE/LTE-Advanced in 4G). In that manner, regarding the IMS standardization, TISPAN NGN Release 1 specifications are mapped on corresponding 3GPP Release 7 specifications, and TISPAN NGN Release 2 specifications are mapped on corresponding 3GPP Release 8 specifications. Cont…. (i) Identify the following items: c. 3GPP Role Definition:  3rd Generation Partnership Project (3GPP) is a collaborative project aimed at developing globally acceptable specifications for third generation (3G) mobile systems. Role:  The 3GPP caters to a large majority of the telecommunications networks in the world. It is the standard body behind UMTS (Universal Mobile Telecommunications System), which is the 3G upgrade of GSM.  3GPP has played important role in the NGN standardization by generating specifications for so-called common IMS in 3GPP Release 8, finished at the beginning of 2009.  It is the same 3GPPreleasewhichstandardizedtheLTEintheradioaccessnetwork(EvolvedUMTSTerrestrial Radio Access Network – E-UTRAN) and System Architecture Evolutions (SAE) based on all-IP principle (in access and in the core networks) which is also compatible with the NGN specifications.  Also, 3GPP closely collaborated with the TISPAN (from ETSI) regarding the TISPAN NGN Releases1 and 2 and relevant ETSI specifications for them,which were incorporated in 3GPP Releases 7 and 8, respectively. (i) Identify the following items: d. IEEE Role Definition:  The Institute of Electrical and Electronic Engineers (IEEE) is a global association and organization of professionals working toward the development, implementation and maintenance of technology-centered products and services. It works solely toward innovating, educating and standardizing the electrical and electronic development industry. Role:  The importance for the IEEE for NGN is due to their standards on access networks which are IP-native from the beginning, such as Ethernet (IEEE 802.3 standards group) and wireless networks including WiFi (IEEE 802.11 standards group) as Wireless Local Area Network (WLAN) and WiMAX (IEEE 802.16 standards group) 3.3 Understand All-IP Network Concept for NGN Introduction  NGN are all-IP networks.  However, they are established as an evolution of PSTN and PLMN on one side and best-effort Internet on the other side to a single network which will be a networking platform for all types of services, existing ones and future ones. Cont…. Figure 3.3 the evolution from PSTN and PLMN toward the NGN is performed by gradual replacement of TDM-based transport systems and interfaces (e.g., SDH), circuit-switching (e.g., phone exchanges), and SS7 signaling (packet- based, separated from the user traffic, but it is not IP-based), with IP-based transport, for example, over DWDM (dense wavelength division multiplexing), IP/MPLS (Multi-Protocol Label Switching), and IP-based signaling (e.g., SIP), respectively. Figure 3.3: NGN (i) Explain All-IP Network Concept for NGN  Since all networks have IP protocol on the networking payer (OSI-3 layer) it is referred to as the all-IP principle. Currently, there is no alternative option on the networking layer and that is good for the convergence. And the convergence is going under the NGN framework. However, NGN is not a type of system, such as GSM, ADSL (asymmetric digital subscriber line), or WiFi, but it is a framework where different architectures can be built and different services can be offered by using the same rules for their implementation, given in the NGN recommendations.  NGN specifies IP on network layer end-to-end, and such requirement defines the all-IP network concept. That means that all access, core (or backhaul), and transit networks in NGN must be IP based.  IP hides the lower protocol layers (OSI-1 and OSI-2) from the upper layers so an NGN can have single network infrastructure and single service platforms for different fixed and wireless access networks.  In all-IP transport networks (used partially for core and transit networks in NGN) usually MPLS is used between OSI-2 and OSI-3 layers (therefore, MPLS is noted as an OSI layer 2.5).  In all-IP principle the interconnection between different networks is also done via IP Cont…. Figure 3.4: All IP Network Concept for NGN Cont….  In all-IP principle the interconnection between different networks is also done via IP links established between pairs of gateway routers or controllers. The all-IP network concept in NGN is illustrated in Figure 3.4.  Since all networks have IP protocol on the networking payer (OSI-3 layer) it is referred to as the all-IP principle. Currently, there is no alternative option on the networking layer and that is good for the convergence. And the convergence is going under the NGN framework. However, NGN is not a type of system, such as GSM, ADSL (asymmetric digital subscriber line), or WiFi, but it is a framework where different architectures can be built and different services can be offered by using the same rules for their implementation, given in the NGN recommendations. 3.4 Apply the understanding of Migration in PSTN Networks to NGN Migration of PSTN Networks to NGN  The Public Switched Telecommunication Networks (PSTN) including its enhancement ISDN (Integrated Services Digital Network) are migrating to all-IP networks with QoS (Quality of Service) support end-to-end for traditional telecommunication services (i.e., telephony) and signaling capabilities required for QoS-enabled real-time services.  initially NGN is targeted for replacement of circuit-switching telephony with IP-based telephony end-to-end with all capabilities provided previously in PSTN/ISDN. Migration from PSTN/ISDN to NGN is also referred to evolution to PSTN/ISDN evolution to NGN. Cont…. Evolution of PSTN to NGN is a process in which parts or segments of the existing POTS networks are upgraded or fully replaced to corresponding NGN network elements providing similar or better functionalities than its predecessors, and at the same time attempting to maintain the services as provided by the original network (e.g., PSTN/ISDN). However, NGN provides additional capabilities and functionalities to existing services in PSTN/ISDN. The NGN maintains the traditional services in their original form by using PSTN/ISDN emulation and simulation (i) Show Evolution of PSTN/ISDN to NGN  To consider the evolution toward the NGN one needs to analyze the migration of different entities in PSTN/ISDN as following: a. Transport network: This include access and core networks with User Access Module (UAM), Remote User Access Module (RUAM), Access Network (AN), as well as switches (i.e., exchanges) in the core network and their interfaces. b. Signaling network: This is overlay signaling network with functionalities typically integrated with exchanges in the network. c. Management: This refers to the management of the PSTN exchanges. d. Services: Different services are implemented within exchange hosts [e.g., roaming in PLMN (Public Land Mobile Network), value- added services, etc.]. Cont….  So, all functionalities in PSTN/ISDN are located in an exchange, although there are exchanges on different layers such as Local Exchanges (LEs), Transit Exchanges (TEs), and international exchanges.  On the other side, in NGN different functionalities may be spread across many network elements.  For migration from PSTN/ISDN to NGN there are several aspects that need to be considered, such as transport, leased-lines, services, and supplementary services (e.g., call forwarding, call barring, etc.), E.164 numbering scheme for telephony services, interworking, and so on.  The migration to NGN includes migration of PSTN/ISDN access networks and core networks.  While there can be different access networks (including fixed and mobile ones), there is convergence regarding the core network of the NGN. Cont….  In general, there are several possible migration scenarios of PSTN/ISDN core network to NGN, given as follows: Call Server (i.e., Soft Switch) based scenario for transition of PSTN core network with three different possible scenarios: - Scenario 1: Migration starts from LEs. - Scenario 2: Migration starts from TEs, with immediate use of packet switched network to which are connected LEs. - Scenario 3 (One-step approach): This is the evolution of both LEs and TEs to packet-based (i.e., IP-based) network nodes. One step evolution to IP Multimedia Subsystem (IMS): This is based on implementation of Core IMS entities in the network. Cont…. Figure 3.5: IMS-based evolution of PSTN/ISDN to NGN 3.5 Understand Signaling Protocols for NGN  In NGN, the signaling is one of the most important advantages over the best effort Internet architecture.  However, since NGN is based on Internet technologies, the signaling protocols (for exchange of control information between NGN entities) are also standardized protocols from the IETF (Internet Engineering Task Force). The most important among them are Diameter and SIP.  The others protocol are H.323, SIGTRAN (Signaling Transmission) and H.248. (i) Discuss Session Initiation Protocol (SIP)  The SIP is a signaling protocol for IP networks, which is standardized by IETF. Its main role in NGN is to establish, maintain, and terminate multimedia sessions.  SIP is considered as a replacement for SS7 signaling in PSTN and PLMN, which has been reliable and complete signaling for real- time services (e.g., voice) in fixed and mobile environments.  Hence, it is standardized as a signaling protocol in IMS, which is an essential part of the NGN for real-time multimedia services.  In general, SIP can be used for creation of two-party sessions (e.g., VoIP), multi-party sessions (e.g., conference), or multicast sessions (e.g., IPTV).  SIP is created to be inherent of the underlying transport protocol, so it can be implemented over TCP, SCTP, or UDP. Cont…. SIP MESSAGE  SIP is a text-based protocol similar to HTTP [and HTTP was similar to SMTP (Simple Mail Transfer Protocol) for e-mail communication]. Similar to HTTP, SIP uses messages in a request/response manner.  SIX messages are defined as in figure below: SIP messag es OPTION REGIST INVITE ACK BYE CANCEL S ER Cont…. SIX MESSAGES  SIP defines six messages used for session setup, management, and termination, and they are given as follows: a. INVITE: This message is used by the caller to initialize a session. b. ACK: This is a message with which the caller acknowledges the answer of the call (which is initiated with the INVITE message) by the called party. c. BYE: This message is used to terminate an established session. d. CANCEL: This message is used to cancel already started initialization process (e.g., it is used when a client sends an INVITE and then changes its decision to call). e. REGISTER: This message is used by SIP user agent (in user equipment) to register its current IP address and the SIP URIs for which the user will like to receive calls. f. OPTIONS: This message is used to request information about the capabilities of a caller, while it does not setup a session (a session is setup only with the INVITE message). Cont…. SIP ADDRESS  SIP is flexible in specifying the address.  In SIP, an email address, an IP address, a telephone number, and other types of addresses can be used to identify the sender and receiver.  The address needs to be in a standard SIP format.  SIP Format  IPv4 address : sip:[email protected]  E-mail address : sip:[email protected]  Phone Number : sip:rais@09-5655300 Cont…. SIP SIGNALING  The SIP signaling process is simply a series of requests and acknowledgements between software agents – known as 'user agents’–acting on behalf of a user or in animate computer equipment.  A simple example is given which shows the SIP message flows involved in establishing and clearing down a multimedia call, say voice and text, between users associated with computer terminals A and B.  The user agent for A (resident in the software of A’s computer) generates an ‘invite’ message which is conveyed to B over the appropriate data network–usually an IP network. User agent B responds positively with an ‘OK’message, to which user agent A responds with an ‘acknowledge’ message.  The media session is thus initiated; these session it self comprises a flow of data (IP )packets between the A and B computers. Cont…. Figure 3.6: A simple session using SIP Cont…. A simple session using SIP consists of three modules (Figure 3.6): i. Establishing Establishing a session in SIP requires a three way handshakes. The caller sends an INVITE message to begin the communication. If the called party willing to start the session, he sends a reply messages (OK). To confirm the session, a reply code has been received, the caller sends an ACK messages. ii. Communicating After the session has been established, the caller and the called party can communicate by using two temporary ports. iii. Terminating The session can be terminated with a BYE messages sent by either party. (ii) Explain the following items: a) H.323  H.323 is An International Telecommunications Union (ITU) standard that provides specification for computers, equipment, and services for multimedia communication over packet based networks that defines how real-time audio, video and data information is transmitted.  It was first defined by the ITU in 1996 and has been updated regularly. The most recent version is H.323 version 7 (2009).  The H.323 standard addresses call signaling and control, multimedia transport and control, and bandwidth control for point-to-point and multi-point conferences.  H.323 is commonly used in VoIP, Internet Telephony, and IP-based videoconferencing. (ii) Explain the following items: b) SIGTRAN  SIGTRAN is the name, derived from SIGnaling TRANsport, of the former IETF working group that produced specifications for a family of protocols that provide reliable datagram service and user layer adaptations for Signaling System and ISDN communications protocols.  The SIGTRAN protocols are an extension of the SS7 protocol family. It supports the same application and call management paradigms as SS7 but uses an Internet Protocol (IP) transport called Stream Control Transmission Protocol (SCTP), instead of TCP or UDP. Indeed, the most significant protocol defined by the SIGTRAN group is SCTP, which is used to carry PSTN signaling over IP. (ii) Explain the following items: c) H.248  The Gateway Control Protocol (Megaco, H.248) is an implementation of the media gateway control protocol architecture for providing telecommunication services across a converged internetwork consisting of the traditional public switched telephone network (PSTN) and modern packet networks, such as the Internet.  H.248 is the designation of the recommendations developed by the ITU Telecommunication Standardization Sector (ITU-T) and Megaco is a contraction of media gateway control protocol used by the earliest specifications by the Internet Engineering Task Force (IETF).  The standard published in March 2013 by ITU-T is entitled H.248.1: Gateway control protocol: Version 3. (ii) Explain the following items: d) Diameter  The Diameter is a protocol that is standardized by IETF with aim to solve the problems with its predecessor, the RADIUS (Remote Authentication Dial In User Service) protocol.  Diameter is an authentication, authorization and Accounting (AAA) framework protocol, which works on the application layer [according to the OSI (Open System for Interconnection) protocol layering model].  It is targeted for usage by applications for network access as well as IP mobility (including local and roaming scenarios).  Cont…. Figure 3.7: Relationship between network elements in a media gateway control architecture Cont….  The Diameter base protocol provides authentication, authorization, and accounting (AAA) services in 3G, IMS, and 4G networks for applications such as network access and data mobility.  AAA protocols form the basis for service administration within the telecommunications industry, such as deciding which services a user can access, at what quality of service (QoS), and at what cost.  Since the introduction of IP-based technology in a telecommunications network, Diameter protocol has been chosen as the AAA protocol for all fixed and mobile networks.  Diameter has the competitive edge over legacy AAA solutions and is a foundation of EPS (Evolved Packet System), the new core network that supports LTE technology. Cont….  The Diameter name is a play on words from its predecessor RADIUS protocol (Remote Authentication Dial-In User Service).  Diameter has been embraced by the many standards bodies, such as the 3GPP and ETSTI, as the foundation for all AAA functionalities in next-generation networks (NGN).  Diameter was developed as AAA grew to support additional needs, such as policy control, dynamic rules, quality of service, bandwidth allocation, and new charging schemes.  It is also possible for Diameter base protocol to be extended for use in new applications, via the addition of new commands or more Attribute-Value Pairs (AVPs).  Other upgrades in 4G, such as real-time functionality for transactions, can only be handled with Diameter protocol. Cont….  The Diameter name is a play on words from its predecessor RADIUS protocol (Remote Authentication Dial-In User Service).  Diameter has been embraced by the many standards bodies, such as the 3GPP and ETSTI, as the foundation for all AAA functionalities in next-generation networks (NGN).  Diameter was developed as AAA grew to support additional needs, such as policy control, dynamic rules, quality of service, bandwidth allocation, and new charging schemes.  It is also possible for Diameter base protocol to be extended for use in new applications, via the addition of new commands or more Attribute-Value Pairs (AVPs).  Other upgrades in 4G, such as real-time functionality for transactions, can only be handled with Diameter protocol.