Traditional SS7 Protocol

1. Message transfer part 2 (MTP2)

MTP2 corresponds to OSI Layer 3 (the data link layer) and such is the lowest protocol in the stack.Sitting on the phisical layer, its provide a realiable means of transfer for siganling information between two direcly connected singaling point (SPs),ensuring that the signaling information is delivered in the sequence and error free

MTP2 performs the following functions:

1.Delimination of signal units
2.Alignment of signal units
3.Siganling link error detection
4.Siganling link error correction by retransmission
5.Signaling link initial alignment
6.Error monitoring and reporting
7.Link flow control

Message transfer part 3 (MTP3)

The primary purpose of this protocol is to route message between SS7 network node in the reliable manner.This responsibility is devided into two categories:

1.Signaling message handling (SMH)

2.Siganling network management (SNM)

SMH is concerned with the routing message to the appropriate network destination.Each node analyzes the incoming message based on its destination point code (DPC) to detemine whether the message is destined for that node.If the receiveing node is the destination, the incoming message is delivered to the appropriate MTP3 user.If the receiving node is not the destination and the message has routing capability, i.e, is an STP, an attempt us made to route the message
SNM is set of message and procedures whose purporse is to handle network failure in a manner that allows message continue to reach their destiantion whenever possible.These procedures work together to coordinates SS7 resource that are becoming available or unavaiable with the demand of user traffic

ISDN user part (ISUP)

ISUP is responsible for setting up and releasing trunk used for inter exchange calls.As its name implies, ISUP was created to provide core network signaling that is compatible with ISDN access siganling.The combination of ISDN access signaling and ISUP network signaling provides end to end transport mechanism for signaling data between subscribers.ISUP provides siganling for both non ISDN and ISDN traffic, in fact the majority of ISUP signaled traffic currently originates from analog acccess signaling like that used by telephone service phone

The primay benefits of ISUP are its speed,increased signaling badwidth and standardization of message exchange.Providing faster call setup times than Channel Associated Signaling (CAS), it ultimately uses trunk resource more effectively.The difference in post dial delay for calls using ISUP trunk is quite noticeable to the subscriber who make a call that traverses several switches
ISUP consists of call processing, suplementary service and maintenance functions.

Signaling Connection Control Part (SCCP)

SCCP sits on top of MTP3 in the SS7 protocol stack.The SCCP provides additional network layer function to provide trandfer of noncircuit-related (NCR) signaling information,appliation management and alternative and more flexible methods of routing
SCCP was developed after the MTP and together with the MTP3 it provides the capabilities corresponding to layer 3 of the OSI references model

SCCP provides the folowing additional capabilities over the MTP:

1.Enhance MTP to meet OSI layer 3

2.Powerfull and flexible routing mechanism

3.Enhance transfer capability, including segmentation/reassembly when message is too large to fit into one Message Signal Unit (MSU

4.Connectionless and connection-oriented data transfer services

5.Management adn addressing of subsystem (primarly database-driven applicaiton)

Transction capabilities applicaiton (TCAP)

TCAP allows service at network to communicate with each other using an agrees upon of data elements.Prior to SS7, one of the problem with implementing swtiching service beyond the boundary of the lcoal switch was the propreitary nature of the switches.TCAP provides a generic interface between service that is based on the concept of componnents.Componnects comprise the instructure that service applications exchange at different nodes Read More..

FMC solution

Telecom convergence on IP networks has been underway for at least a decade, as both carriers and entrprise have sought to replace separate,single purpose infrastructures with integrated,multi service ones.This is evolution is reflected in the convergence of voice and data in enterprise campus IP telephony,consumer VoIP services and local carroer Digital SUbscriber Line (DSL) services.FMC merges service in the fixed line and mobile telecom worlds,as exemplified by voice roaming between a cellular network and a campus voice enable WLAN.
In its ultimate form,FMC reflects a true integration of underlying network and aasociated management infrastructures.But there are several interim steps in the way to the most seamless form of FMC

Broadly speaking,carriers rollouts of converged services begin with simple service bundling,followed by real integration of underlaying network infrastructure,followed by integration in operations support system (OSS). The baby step of carrier servies bundling can be taken without any techincal integration between the fixed and the mobile network, and only a consolidation of previously separate customer interface, e.g, single sales contact instead of two; an integrated support and help desk function and single bill for both mobile and fixed services.

The customers get some modest benefits in terms of consolidated purchasing and discounting leverage as well as fewer carriers to deal with.The carriers get some modest uptick in customer retention and can market its entry into FMC. Such service bundling is already taking place today,but that barely scratches the surface of FMC's potential

The benefits of FMC appear much more compelling to both the enterprise customer and the carrier once the underlying fixed and mobile telecom infrastructures - plus OSS functions for management, provisioning and billing - begin to converge.

The evolution toward true FMC service is projected to proceed through five major phases:

1. Phase 1: Basic network infrastructure convergence

already well underway.The carrier consolidates voice traffic onto its IP WAN using VoIP and the enterprise begins moving its campus voice service to some form of IP telephony, often using a hybrid approach than combines Time Divission Multuplexing (TDM) and VoIP.The main benefits are cost savings through reduction in capital expenditures for network infrastructure for network infrastructure and in operating expenses to maintain it

2. Phase 2: Addition of enterprise wireless LANs, followed by voice over WLANs

Party to well underway at most large enterprise. Enterprise WLANs move from limited deployments serving nomadic users in conference room and lobbies to ubiquitous campu wide coverage, serving as the primay means of network acccess for all users.Greater integration of wire and wireless LAN infrastructure begins , e.g the use of common authentication mechanisms and endpoint security plociy is enforced for both wired and wirelss LAN users,thus deploying voice over the WLAN

3. Phase 3: Early managed FMC services

were underway as of 2006. Carriers and carrier partnership begin to roll out the first managed FMC services, providing mobile users with the ability to roam seamlessly between cellular netwrok and enterprise voice enable WLANs, using dual mode handsets or PDAs equipmed with both Wi-Fi and 3G radios

4. Phase 4: Tighter integration of fixed and mobile network infrastructure and back office system

Begin in late 2007, with broader adoption expected in the beginning of 2009. FMC carriers and their partners began to functionally converge their network signaling and back office system. Consolidation of formely separate control paths for service setup and feature delivery enable new services beyond cellular to voice - over - WLAN roaming - e.g, push to talk voice and application like instant message that exploit a user's presence and availability profile

5. Phase 5: High value FMC application delivery

As the undustry matures and accelerates through 2011. With a truly integrated, multimedia infrastructure in place that supports any combination of information types, end device and access technologies, FMC providers begin to focus their efforts to developing new application services. They take further advantage of converged network' presence awareness, effectively delivering services to specific persons rather than device or via specific access networks.

Providers begin creatively mixing and matching once disparate services - voice, audio conferencing, video, video conferencing, text based instant messaging, email, games, SIP enabled conferencing and collaboration, broadcast video and audio - to serve an array of new applications and end user needs Read More..

DPI (Deep Packet Inspection)

The rapid growth and popularity of broadband service presents both opportunities and challenge for carriers. On the other hand, the popularization of such service as, P2P,online games,WebTV and VoIP means that many people are now using and enjoying these service and telling their friends abotu them, so the number of usrs is growing larger everyday. On the other hand,carriers now have to resolve a series of problems in relation to bandwidth management,content billing and information security

The most obvious problem has to do with P2P application.P2P technology in effect clears a path through the C/S traffic model.By adopting a non concentrated server mode, it is able to penetrate and break up server bottleneck and so it is now being widely used in many domains including downloading,streaming and VoIP.According to the statistic data, at present, P2P traffic accounts for over 50% of all online traffic and the percentage is growing higher all the time.Many people are even saying that P2P is a killer application or revolutionary technology.However most carriers' network planning and construction mode are not suitable for the P2P applications traffic model

In addition most network equipment is lacking int terms of efficient technical monitoring, so P2P application would not recognized if used. As a result,carriers are unable to properly identify or manage network applications.Hence their networks are always congested and operations are in a state of confusion pr facing some technical dilemma

Another barrier reratding carriers' development is that they are unable to implement content billing.Content billing means that a carrier is able to perform in depth analysis in data packets,differentiate type of user service and set reasonable rates according to service features
At present, as data services and content services have been developing, the lack of complete content billing modes make it virtually impossible to convert service increase into equivalent benefits.

What makes things worse is that the benefits derived from some services have even decreased. In providing voice, IM (instant messageing) and game applications, ISP and ICPs utilize cheap network resource to attract and develop users and recieve a huge portion of the profits. leaving carriers helpless, receiving an insubstantial portion of the profits.

Thus far content billing become an important threshold feature upon which are wireless carriers have started to deploy content billing and fixed netwrok carreirs are also investigating useful steps in this direction

Content security presents another headache for carriers.Over the past few years, intrussions and attacks from online hackers have resulted in huge loss for carriers.Although a firewall can repel some of these attacks, it offers little if any protection againts viruses that are hiden in IP packet net loads.Currently, network attacks have been gradually shifted toward high level application.According to recent statistics released by Gartner, the application layer has been the target of over 70% of network attacks, and the percentage is still increasing steadily.Therefore,content security has become a key focus in information security

While carriers are failing to identify services, implement content billing and not meeting information security demands, they are on the one hand being forced to pay more in terms of operation costs and are recieving lower customer satisfaction in return. Therefore, a major concern for carriers is acquiring the ability to perceive network applications and provide network service control and management measures, so that their networks are both operable and manageable

A positive step in this direction is the recent development of DPI.Deep Packet Inspection is a new technology is comparasion to ordinary message analysis.Ordinary message inspection only analyze contents under layer 4 of each IP packet, which includes the source address, destination address, source port, destination port and protocol type.So on this basis DPI is capable of implementing analysis on the application layer that can identify applications and their contents

In fact, DPI technology has already been applied in the security protection system of intranets.Since its application scope is relatively samll, it has thus far not attracted much attention,However the forces that are currently driving it to center stage are P2P application and content billing Read More..

Metro Transport network

MSTP is based on SDH,can enjoy existing SDH network resource and provides various interface to support data service such as ethernet and ATM.Through the analysis of SDH network operational,maintenance and management experience,MSTP is fully compatible with existing TDM service and can integrate multiple service transport and access to meet upward spiraling data service commands.

Fro traditional carriers with mature SDH network offering a huge quantity of TDM service,MSTP is the most direct and efficient metro transport network solution.

MSTP has been widely applied and most new metro SDH networks are MSTP.To efficienly process and transmit data service,it utilize some key technologies including GFP,VC (virtual connection) and LCAS (Link capacity adjustment scheme).As MSTP is TDM based,the service mode it suits is the provision of traditional TDM service while partially supporting IP and ATM service.

MSTP can be located on the convergence adn access layers of a metro transport network and can integrate service networks into both

The existing network environment bears traditional TDM services, whereas MSTP can reliably bear new,high capaity services such as ethernet leased line,point to multipoint and ring services.Integrated access with convergence from DSLAM to BRAS can be offered to large scale customers and it can also transmit NGN and 3G services

MSTP mainly exist as a layer 1 network and is not suitable for large scale layer 2 and layer 2 services.Ehen introducing MSTP,carriers should ensure that existing networks can coordinate and coorporate.MSTP can mainly offer existing metro network and ATM networks access and convergence functions, and it can be used to expand the ethernet and ATM service coverage.Its data processing function effeciently handles data services but it can not wholly replace data service networks

MSTP related rechnologies have been constantly developed adn optimized.To further improve its perfomance in transmitting ethernet services and balance nodes, some MSTPs adopt embedded RPR (Resilence packet ring),which enables highly efficent data service transport.Given RPR only supports ring network topologies,some MSTPs adopt built in MPLS (multi protocol lable switching) to process inter ring services

As MAN bandwidth demands have been soaring,it is increasingly difficult for SDH based MSTP to cater to MAN developments. A trend for solving the MAN bandwidth bottleneck is to gradually introduce WDM into MAN.WDM represents a mainstream technology in terms of long haul transport, but it has only been recently applied to MAN.Metro WDM embodies another type of driving force and characteristic that are different to those of long haul WDM.When used in long haul transport,WDM can save on expensive long haul optical fiber resources.

In the MAN network with its mostly short transport distance, costs on optical fibers will be much lower than in long haul backbones.Node equipment normally incurs high costs in each metro transport network and while it is beneficial to save optical fibers in some MAN,however service flexibility,manageability and cost effetiveness are more important for MAN applications.

The metro WDM network must support multiple services on the same platform and should be transparent to rates and protocols.Equipment ought to be low in price and the network should feature good expandibility in order to adapt to various metro service demands.Wavelength management capabilities must be strong to facilitate rapid wavelength service deployment.

A solid network self healing capacity that matches SDH network is necessary to offer different levels of protection according to services demands.As transmisiion distances in the MAN are alwasys short, there is no unreasonable demand on network capacity, and some cheaper components can be employed to reduce DWDM equipment cost.Alternatively,the network can adopt CWDM,which enable large inter channel distance.Point to point WDM cannot meet the demands of MAN applications so, as ROADM (reconfigurable optical add drop multiplexer) matures, ROADM can enable optical layer networking and introduce the control plane so that WDM plays greater role in MAN networks

Metro optical networks can provide strong bandwidth support for metro IP networks and ethernet.Compared with pure,direct optical fiber connections,this is network is more flexible,secure and resource efficient.The WDM networkcan deploy some new service such as BoD (bandwidth od demand),wavelength wholesale,wavelength lending,OVPN (optical VPN) and optical multicast.As the SDH network on the electronic layer is gradually replaced by IP/ethernet,future metro transport network will adopt the optocal layer metro WDM network Read More..

Fixed Mobile Convergence (FMC)

Following a long period of development, fixed mobile convergence (FMC) appears ready to arrive in the froms of real carrier services for enterprises.The concept of FMC-the ability to access multimedia application from a variety of end user device while roaming across a range of fixed line and mobile networks-has broad appeal.Enterprise see FMC as a way to improve employee efficiency which may also help reduce telecom costs.Carrier look to help them survive and grow in a world where profits from providing mere connectivity and transport for voice and data rapidly dwindling.

Industry analysts are projecting aggresive uptake of FMC services:global sales of dual mode mobile phones are expected to exceed 100 million units by 2010 (per ABI research).FMC revenues may reach US80 billion worldwide by 2009 (per pyramid research)

FMC promises to provide carriers and their partners with a range of new applications and srevices they can deliver to enterprises to drive revenue, profits and customer retention.The first managed services to offer true convergence will allow enterprises users to roam between cellular networks and voice enabled wireless LANs (WLANs),using dual mode handset equipped with 3G and Wi-Fi radios.Carriers considering their own FMC solutions can learn some important lessons from the innovative carriers who brought these services to market in 2006,such as the new functioanllity that WLANs deliver,making mobile voice practical within the enterprises campus

As with all fundamentally transformative processes,the FMC revolution-from our current collection of disjointed fixed and mobile carrier and enterprise network,toward seamlessly interoperating,converged multimedia applicaiton delivery platform-will take place in a series of incremental steps

Carriers and enterprises that anticipate the critical technology inflection points that accompany each major phase in the evolution toward FMC will be able to make smarter decisions on near-term network infrastructure investments


The Role of WLANs in FMC

One of the critical inflection points in the path to FMC is the advent of WLAN infrastructure capable of supporting mobile voice with sophisticated roaming capabilities.Early carrier rollouts of managed FMC services have identified certain limitations inherent in aging WLAN architectures that use independent access points ( so called "fat APs") or a centralized WLAN gateway (the WLAN switch with thin APs approach)

The WLAN component of managed FMC services will have to implement a third - generation architecture - one that leverages discrete,distributed handling of WLAN transport,control and management functions - in order to deliver the following critical features:

1. Definition and enforcement of very granular WLAN quality of service policies,tunable to broad range of application (notable voice and video),end device capabilities and other characteristic

2. A combination of centralized control and access point intellegence to optimize perfomance along the data path to ensure scalability and consistent perfomance.

3. Seamless roaming (handover) between WLAN access points on the same LAN segment and between WLAN access points on different IP subnets

4. Management tools to help carriers centrally monitor,troubleshoot, and maintain WLAN equioment across an FMC customer base that may extend to thousand of locations

5. Features to support an eventual migration to IP multimedia system, including session initiantion protocl (SIP) based VoIP signaling and other SIP-enabled applications and services

6. Access point features to automatically enable to connection of the broadest possible range of end user device and radio types without the need for any end user configuration work

7. The ablitiy to add WLAN capacity in cost effective increments and planning tools that help carriers anticipate and pre emptively address problems with enterprise WLAN congestion,radio frequency (RF) coverage and infrastructure resilency

8. Thigh integration and interoperation with the wired LAN and its bandwidth management,netwrok security and authentication/authorization/accounting (AAA) infrastructure

Carriers considering their first FMC offerings can benefit greatly from the experiences of FMC pioneers and their customers.Talking to vendor reference customers will provide useful insight into how their WLAN infrastructure choice helped or impeded the rollout of FMC services.
At a minimum,carriers should begin to more closely examine the implications of FMC on WLANs as they consider potential vendor alliances.Identifying a WLA solution that can meet FMC's requirement - for multimedia support,quality of service (QoS), perfomance, scalability, managemeability and security - may help carriers to avoid some potentially costly mistakes. Read More..

P2P (Point to Point)

Online video has emerged as the most badwidth hungry application.Some researches have state that video services ocupy 60% of P2P traffic,which each file averaging around 1GB.
Hence VOD and downloads use huge amounts of network bandwidth and this is exerbated if a video is particularly popular.A singel video report covering 9.11,for instance, had a click rate exceeding 100 million

P2P connects peoples in a network and users can communicate directly via the internet rather than though any intermediary.Its application enable users to directly exchange and share file instead of connecting to servers for file browses and downloads..Significanly P2P alters the reality that the internet is the dominant power core as P2P devolves power to users via decentralization, while greatly enhancing the value of online services

However,the wide range of P2P appplicaitons on the internet describes a trend for which it is complicated for carriers to strategize.Its advantages are fairly evident.Firstly,P2P creates new opportunities as it can attract more users to broadband networks that provide these applications.Secodnly,P2P technologies can be used to optimize existing services and networks to increases perfomance and decrease cost.P2P and online TV for example represent a good combination.

Based on existing services, carriers can explore new P2P operation and profit models to render these application managable and profitable, and allows them to develop in a constructive,sustaibale way that caters to user requirements

The most obviously negative aspect is that if P2P applications are all interconnected in parralel, network bandwidth increase tremendously.In extreme cases, this may result in network congestion and the perfomance degradation of other internet application.Moreover, P2P based voice communicaiton technologies such as Skype have direclly threatened carrier's traditional voice communicaiton services

Given these considerations,carriers are left with two broad strategies:Prevent the use of P2P or develop and guide sustainable usage.Since P2P represents an irreversible trend,logic dictates that usage guidance is the better long term option,despite the fact that the challenges currently outweigh the opportunities.Correct decision making and implementation will be the tool to heighten the potential benefits

Many carrier have in fact started developing solutions for P2P apllication.Carriers should prevent illegal network resource usage,while exploting P2P applications' inherent advantages and transform then into something useful

Three strategies can be followed to reach this goal.The first is to limit overall bandwidth.Traffic should be localized to reduce pressure on the backbone network.The second is to employ P2P technologies to reconstruct existing networks,thereby increasing perfomance and reducing cost.Thirdly,P2P technologies can be used as a platform to develop new services and increase income.Some carriers have already started expanding network bandwidth


Adjust MAN architecture


Both P2P software download such as Bit Torrent, and live broadcast P2P software including PPLive are executed via applicaiton layer duplcations between node.In the present MAN architecture,users exist in a dual layer separation mode in the acces network.

Application layer duplication between users can only occur through the core convergence layer of the MAN or the backbone network and the bandwidht consumed on the MAN core convergence is proprotionate to the numbers of users

The present MAN see data traffic passing the convergence swtiches and BRAS before arriving at the MAN egress.No fixed bandwidth is reserved for each users from the access layer to the MAN egress and whenever a large amount of traffic exists on the access layer,much bandwidth will occupied on the convergence layer or the backbone network.Moreover ADSL bandwidth in the access network is asymmetrical as uplink bandwidth is fast less than downlink bandwidth.If application layer duplications are implemented,uplink bandwidth demands are increased,which would exeed present access network capacities.

If P2P services become mainstream services over present network architecture,badwidth on the MAN core convergence netwrok will see the greatest bottleneck,while access layer bandwidth will be continously occupied.In terms of online TV applications, P2P duplications on the application layer are not cost effective in term of bandwidth usaged compared with multicast.Network access can only adjust MAN architecture so that it can adapt to the P2P application layer duplication model and reduce pressure on the MAN convergence layer's P2P derived bandwidth demands.

To make the MAN architecture suitable for P2P applications layer duplications, the following principles should be obsreved:

1. Selecting symmetrycal access equipment

DSLAM is continously used by carriers but possesses asymmetrical access equipment that cause significanly more downlink abdwidth than uplink. It is rather suitable for C/S model than P2P.Therefore a shift toward symmetrical access technologies such as LAN,ADSL2+ or EPON is recommended

2. Flattering the access network

The nature P2P traffic means that placing the layer 3 gateway closer to users will increase bandidth saving on the MAN core convergence layer

3. Building a full meshed structure at the core convergence layer

MAN currently adopts a dual start,tree structure.All traffic passing MAN must cross two routers at he MAN core.This is unsuitable for P2P traffic,adaptation to which necessitates the adoption of multi node architecture at the MAN core layer under which different nodes network via the full meshed Read More..

Building a secure network

The internet begans as an experiments in 1969 by ARPA of the US Departement of defence.ARPA's intention was to create a very reliable digital communications network that could be used in wartime, so communication could be maintain even if the stations or physical links were targetted during attacks.Early researches into this area adopted an innovative and powerfull idea - packet switching- to build the ARPANET.Subsequencely the new technology proved to be highly successful.In the following years, more research networks were created and the ARPANET evolved into the NSFNET, before finally becoming the Internet we know today.

The internet began into rouse the interests of the public during the 1990s, partly due to the wide applications of PC and WWW.Soon access to the internet became a popular services of the residential customers as well as enterprises and the number of internet users has increase exponentially over the years, so much so, that as of the end of 2006, the number of people using the internet has sky rocketed to 1 billion worlwide.

As a public communcaiton service, the internet access has to reliable.However the kind of reliability that ARPA was looking for was actually robustness,that is, the capability to function correcly under negative impacts, so commands can be delivered to the outposts to coordinate attacks, even after some stations had been destroyed.In comparasion, the kind of reliability that the public needs is high availability.That is the proportion of the time whe the service is available, which is this instance, should be most of the time

Accoring to the Infocomm Development authority of Singapore, the availability of internet service provide by major ISPs in Singapore about 99.99%.In other words, internet service is unavailable and cannot be accessed for a little than a hour each year
Since the most people use the internet for seding email, browsing news sites,searching for information,etc, and for basically nothing very critical, then most people are satisfied with the service.

The new millenium has withnessed the coming of network convergence.A fair portion of long haul calls had been packetisez nad routed to the internet and now ILECs are beginning to replace PSTN with IMS.Succesful deployments of IPTV by pioneer telecom operators have helped to showcase the revenue and profit potential and triple play service and triggered a new wave of expansion of IP networks globally.As a result, more and more enterprises are switching to IP VPN to replace the expensive frame relay ceoonections.As the telecommunication network is heading into an all IP era, the internet will become the common IP bearer network for all kinds of new services.

Glory is always accompanied by a heavier sense of responsibility.Telecom operators established the availability standarad for PSTN and leased circuits long ago, five 9s (99,999%) which translate into 5 minutes downtime per year.Cable operator have a similar availability satandard for cable TV.In order to bear the traffic multy-play or VPN services, the IP bearer network has to be revolutionized,hence,improving availability from four 9s, to five 9s

To make the task even harder,some services are session based such as voice service. If the call is broken then the call is dropped and customers have to dial again.To effectively deal with this issue,the IP bearer network has to provide a fast automatic oath swichover mechanism to re reroute the traffic,like,SDH or PSTN, which are able to provide 50 milliseconds automatic protection

Is summary, as the common IP bearer network in All-IP era, the IP bearer network needs to be able to provide four 9s for internet access, five 9s for voice,IPTV and VPN, as well as a fast path switchover mechanism for session based services Read More..