SS7ware’s insights from the MVNOs World Congress

VNOs World Congress 2017 (1)

We just got back from the MVNOs World Congress, in Nice, where we did quite a good impression with our YateHSS/HLR and YateUCN solutions for MVNOs. The “not so shocking” conclusion that we came to was that our public pricing policy impacts the MVNO market at its core.

We already knew that, so the real benefit of the conference for us was that we got closer to the needs of our customers by talking to them about their troubles as MVNOs, MNOs and IoT MVNOs.

We share the knowledge, so here are some of the insights:

1. MVNOs need our network equipment (YateUCN as a GMSC, GGSN, PGW and YateHSS/HLR) because of the flexibility given by the features included in the Yate software and the use of off-the-shelf hardware.

In the case of the YateUCN (unified core network) the Yate software implements the functionalities of 2G/3G/4G core networks in a single server. We made it that flexible in order to ease the businesses of MVNOs and MNOs as well. YateUCN works for MNOs as MSC/VLR, SGSN, SGW.

2. full MVNOs choose our products because their businesses aren’t sustainable on the long run with big vendors’ products (such as Cisco, Huawei) that ask 4 times the costs of an YateHSS/HLR for an upgrade.

As the network grows, the CAPEX and OPEX expenditures/subscriber decreases significantly with our MVNO solutions. We charge per license and once your network grows in number of subscribers, you just add another server in a cluster. The YateUCN and YateHSS/HLR solutions are scalable, redundant and load-balanced due to the clustering module implemented in the Yate software.

3. the IoT MVNOs use our GGSN/ PGW solution (YateUCN) to offer mobility to the IoT devices and a positive return on investment for the MVNO business, within 6 months or less.
SS7ware’s full IoT MVNO network solution consists of two products, YateUCN and YateHSS/HLR, both with license costs at $31050, which is about $0.62/ device for a network of 100.000 devices.

4. the strategy of MNOs is to officially sustain MVNOs businesses, because MVNOs play well on the segmented markets and by doing this, they take market shares from competition.

Please feel free to send us questions at sales@ss7ware.com or visit our website, http://www.yatebts.com, to learn more about SS7ware’s MVNO solutions.

Hope to see you in November at the MVNO Conference in London.

SS7ware Inc.
Contact
0040-726-183-753
www.yatebts.com

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Ditch the Online Charging System

YateUCN removes the need for an Online Charging System for new LTE operators by providing a minimum Guaranteed Bit Rate (GBR) for all subscribers.

In a typical mobile network, the Online Charging System (OCS) sets a maximum allowed bit rate based on available credit to prevent high demand users from congesting the network. The OCS needs to keep track of all the pre-paid accounts of an operator’s subscribers, making it complicated and expensive.

The YateUCN EPC is the alternative that lets the operators set a minimum GBR on the default bearer. This way, it ensures that the network is usable for everyone, even in congested cells, eliminating the need for the OCS.

How it works

YateUCN, through its MME/PGW nodes, allows operators to set a Guaranteed Bit Rate for the default bearer of an UE, so the bandwidth is divided fairly to the connected subscribers supported by the same eNodeB.

Though unusual, this feature works because the eNodeB does not care which bearer is the default bearer, and the UE follows whatever bandwidth scheduling it is given by the eNodeB.

guaranteed_bit_rate_blog

The Guaranteed Bit Rate is set in the MME/PGW components of the YateUCN EPC server though a JSON API. The bit rate is then implemented by the eNodeb.

The Guaranteed Bit Rate works for local data traffic, but not for data roaming, so it is a great solution for former ISP or cable operators switching to LTE, whose main customers are fixed, non-roaming subscribers.

A few final words

Small LTE operators, former ISP or cable operators or operators switching from WiMAX to LTE, have to deal with a lot of hurdles when installing their network. The Online Charging System is one they can forget about. YateUCN allows operators to lower their CAPEX without making any changes to their OPEX, while ensuring that their subscribers have continuous access to the data network.

YateUCN, the EPC cloud

The YateUCN is an LTE EPC that unifies all the functions of a conventional LTE core network into a single server. A single YateUCN unit combines the MME, SGW, PGW, PCEF and PCRF functions. A pool of YateUCN servers provide seamless horizontal redundancy, scalability and load balancing in the LTE core network. The YateUCN also replaces the latest core network approaches to design and management, such as network function virtualization (NFV) that virtualizes the functions of the network’s nodes in software or software-defined networking (SDN) that splits the control plane from the user plane.

A conventional LTE core network has many components and each requires a back-up node for redundancy. To ensure load balancing, operators need to deploy load balancers and external servers, which only add to the complexity count.

The YateUCN servers that form the EPC cloud have a many-to-many relationship with the eNodeBs, are equal at application lever, and eliminate the single point of failure between the RAN and the core network. All these characteristics allow for horizontal redundancy, load balancing, easy management and an overall simplicity within the network.

yucn_redund_epc_2015-11-18_version1.2_compare1.1

Redundant EPC

In conventional LTE networks, all core network components (MME, SGW, PGW, PCEF, PCRF) need to be duplicated to ensure redundancy and synchronization in case of failure. With a YateUCN-based core network, operators add extra servers to the existing pool to increase the network’s overall capacity.

To achieve redundancy, subscribers get assigned to random servers from the YateUCN pool. If a YateUCN fails, all the devices served by that unit are automatically re-assigned to other available YateUCN servers, as seen in the diagram.yucn_redund_epc_2015-11-18_version1.3

LTE core network cloud

A cluster of YateUCN servers act as an LTE core network cloud, providing all the EPC services: mobility, authentication, quality of service, routing upload and download IP packets, IP address allocation and more. Mobile operators eliminate the occurrence of a single point of failure between the RAN and the core network because YateUCN servers are equal at application level, and have a many-to-many relationship with the eNodeBs.

By removing the single point of failure possibility, mobile carriers can build scalable and considerably leaner core networks, while also providing load balancing for enhanced flexibility.

Each YateUCN core network server is implemented in off-the-shelf servers commodity software (Linux), offering a shorter lead time, more servicing options and faster replacement time.

Integration in existing LTE networks

The entire LTE EPC layer is implemented in a single YateUCN unit, meaning that it replaces the MME, the SGW, the PGW, the PCEF and the PCRF units of conventional networks.

The YateUCN is compatible with any generic LTE RAN and core network component. It supports the S1-AP and GTP interfaces between its MME and SGW functions and the eNodeBs. The YateUCN uses Diameter (S6a) to connect to an existing generic Home Subscriber Server (HSS). The unified server can connect to external PGW and SGW via the S5/S8 interface. To link to an existing IMS, to the Internet or to an MMS service, the YateUCN uses the SGi interface. Finally, to interrogate an external Equipment Identity Register (EIR) about blacklisted IMEIs, the YateUCN uses S13 over Diameter.

Additionally, the YateUCN also implements the IMS functions necessary for deploying VoLTE, but this will be detailed in a future article. In the meantime, previous blog posts have detailed the YateUCN’s VoLTE call with an iPhone 6 or how the YateUCN handles SRVCC.

A few final words

A unified core network server that delivers redundancy, scalability, load balancing and flexibility allows mobile operators to tap new core network equipment innovations and reduce their CAPEX. Easily integrated in an existing LTE network, the YateUCN makes it possible for mobile carriers to optimize their networks and replace solutions typically characteristic to the recent mobile LTE deployments, such as NFV or SDN.

YateUCN – the redundant MSC/VLR

Traditionally, the redundancy of the Mobile Switching Center / Visitor Location Register (MSC/VLR) is obtained through redundant dedicated hardware and software. The problem lies in the Abis + A interfaces (BSSAP protocol) which do not allow a base station to move easily to another MSC/VLR. To overcome this problem, we decided to use the SIP protocol (with enhanced features for GSM operations), which allows a YateBTS SatSite base station to move to another YateUCN (MSC/VLR) automatically and quickly.

Redundant GSM MSC/VLR

In a GSM network deployed with YateBTS-based SatSite base stations and YateUCN core network servers, each subscriber is randomly assigned to a YateUCN from a pool of core network servers. Operators can increase the redundancy of the pool by simply adding additional YateUCN servers for excess capacity in case a unit malfunctions. Therefore, handsets connected to a single SatSite can be served by multiple identical YateUCNs, while, at the same time, a single YateUCN serves multiple SatSite units. If a YateUCN server fails, all the mobile devices served by it are automatically moved to the other available YateUCN servers. When the subscriber is registered to the new YateUCN, its location is updated in the HLR.

In short, YateUCN and the GSM YateBTS SatSite base stations form a many-to-many relationship, and this was made possible though a number of characteristics.

  • The GSM YateBTS SatSite implements all the functions of a conventional Base Station Controller (BSC).
  • The A interface (between the BSC and the MSC/VLR) was replaced with SIP (between YateBTS and YateUCN), making it possible to quickly re-associate handsets with different YateUCN servers.
  • All YateUCN servers are identical units that support many core network functions. Operators will only have to duplicate one component, as opposed to multiple in conventional networks.
  • YateUCN is implemented in commodity hardware (off-the-shelf servers) and software (Linux), delivering a shorter lead time, more servicing options and faster replacement time.

The diagram below illustrates the technology perfectly.

yucn_msc-vlr_2015-11-4_version1.1

Integration in an LTE core network

The SatSite and the YateUCN components are easy to integrate into existing LTE networks because 2G services are delivered in SIP. These GSM services are integrated into a 4G network by employing the same GTP and IMS interfaces that are typically used in conventional EPC/IMS core networks.

YateUCN implements the same SIP switch to both provide GSM services and connect to an existing IMS network. Thus, with both the SIP-powered RAN and core network products, operators’ migration from GSM to LTE turns into a much simpler process.

Integration in a GSM core network

As an MSC/VLR, YateUCN performs all the functions of other MSC/VLRs: mobility, authentication, speech call and SMS routing. The server supports authentication of handsets using the SIM/USIM (EAP-SIM/EAP-AKA) and SIP AKAv1-MD5 algorithms.

YateUCN can connect to any standard HLR via the SS7 MAP protocol, and to other MSCs and GMSCs through the MAP-E protocol, allowing it to be in any conventional GSM network.

A few final words

YateUCN brings something new to GSM equipment: affordable redundancy, scalability, and uncomplicated management into a single core network server. It is easy to integrate to existing GSM and LTE networks and can be easily upgraded with new features within the same hardware and allows operators a seamless network extension.

YateUCN – the solution for MVNO networks

With mobile consumers’ expectations on the rise, new business models proliferate. Mobile Virtual Network Operator solutions must differentiate to stay competitive and maximize their offerings.

MVNOs wishing to offer subscribers high quality voice and/or data services can use YateUCN as a GMSC (voice), a GGSN (GPRS), or a PGW (LTE data).

YateUCN supports billing integration through CAMEL, RADIUS, and Diameter.

YateUCN, the unified core network for GSM/GPRS and LTE is a software implementation of the functions and protocols from the 2G and 4G LTE core layers on a commodity server. For GSM and GPRS, YateUCN performs the functions of the MSC, VLR, SGSN, GMSC, and GGSN. From 4G LTE, it acts as an MME, SGW, PGW, and PCRF.

YateUCN can be used to operate either all of these functions (for MNOs) or one specific function (for MVNOs). Each case scenario is presented below.

mvno_yucn_2014-10-29_version1.2

  • YateUCN for voice (GMSC)

The GMSC (Gateway Mobile Switching Center) functionality serves to locate the subscriber’s HLR (Home Location Register) in a mobile-terminated call, and then to route the call. Based on the information from the originating MSC, YateUCN uses the HLR to find the MSC of the called subscriber; with the number assigned by the HLR, the GMSC then forwards the call to the destination MSC. As a GMSC, YateUCN also provides CAMEL support.

  • YateUCN for data (GGSN and PGW in a single component)

In 2G networks, YateUCN as a GGSN (Gateway GPRS Support Node) is responsible for establishing and maintaining the user’s IP session and for storing billing information. It routes the IP packets to the SGSN in the MNO network over GTP-C. Establishing the data session in the YateUCN core network is independent of the radio network and is performed by the same component which can act either as a GGSN or as a PGW. If a session is initiated in GPRS, the GGSN (YateUCN) will connect to the SGSN over GTP-C v1.

In an LTE network, YateUCN can act as a PGW (PDN Gateway) to assign the IP address to the UE. YateUCN only communicates with the SGW in the operator’s network (over the S8 interface) and supports both Diameter and RADIUS to connect to the charging function in the network. If the session is started in LTE, YateUCN will act as a PGW and will connect to the SGW over GTP-C v2. It is also possible for a session to be started in LTE and continued in a 2G or 3G network.

  • YateUCN for billing integration

YateUCN connects to any billing system used by the MVNO, for both voice and data sessions management. It supports the Diameter Ro interface for prepaid services and the Rf interface for postpaid billing. For real-time credit control over SIP, YateUCN implements the Diameter Credit-Control Application (RFC 4006) to connect to the MVNO’s Charging Server.

  • YateUCN for SIP users

YateUCN also offers support for PC2Call registered users.

The unified core network, YateUCN, provides a profitable and flexible solution for the different requirements of emerging MVNOs. Detailed information about how YateUCN works in 2G and 4G networks is available here.

Increasing the security of VoLTE with YateUCN

The emergence of VoLTE-capable devices is raising new security concerns for mobile network operators, as existing IMS deployments expose vulnerabilities in VoLTE handsets to other devices in the network. YateUCN unified core network brings a solution to these concerns by isolating SIP and RTP call legs between handsets.

b2bua_vs_sip_proxy_2015-10-13_image1

LTE uses an IMS network to deliver VoLTE (voice services), and does so via Session Initiation Protocols (SIPs). This makes the IMS network act as a SIP proxy, performing routing, session control, and registering the UE to VoLTE. Voice is delivered through RTP from one UE to the other. Therefore, in case of a security attack, it is theoretically possible for a third party to send additional information through a forged SIP message via the IMS, to the target UE.

b2bua_vs_sip_proxy_2015-10-13_image2

Voice communication in 4G LTE can also be subject to malicious acts at various layers of the channel, including at the IP packets level, the UDP, RTP, or even the codec level.

What’s more, SIP is also implemented directly in the baseband processor of the latest generation smartphones to allow subscribers to use VoLTE, making it easy to for a potential smartphone takeover to occur.

b2bua_vs_sip_proxy_2015-10-13_image3

For SIP signaling, YateUCN acts as a Back-to-Back User Agent server, ensuring a secure transmission of data. B2BUA allows SIP communication from the originating party (or User Agent) to be terminated at the one side of the network, where the message is verified. Any harmful information included in the received SIP message is eliminated and the message is recomposed to include only the information needed for the SIP to reach the end party.

The risk of attacks decreases since malicious data is not automatically allowed to pass from one UE to the other, and the split SIP messages are negotiated independently on the originating and terminating sides.

Unlike current IMS deployments, YateUCN allows the same message decoding, verification, and re-encoding of RTP by acting as a proxy. This also simplifies the deployment of Voice over LTE, since handsets only need to connect to YateUCN server.

SDN and beyond

Software-defined networking (SDN) and network function virtualization (NFV) are new approaches to designing and operating mobile networks, granting operators better management possibilities and better use of the network capabilities.

NFV represents the virtualization of network nodes roles, which culminates in separate software implementations performing the functions typically executed by hardware components. At the other end, SDN uses the virtualisation technology to split the control plane (where you need flexibility) from the data plane (where you need speed/performance). However, the price for this is complexity which translates into high operation costs.

Operators benefit from such frameworks because they increase the network capacity and performance, and allow for better manageability.

The YateUCN approach recognizes the usefulness of separating the user plane and the data plane, but it implements both of them in software. The control plane is implemented in the user space for flexibility while the user plane in the kernel space for speed.

As a result, operators who deploy YateUCN networks will gain from considerably scaling down equipment, and will have better control over the network scalability and performance requirements. The image below shows the YateUCN implementation and a common SDN deployment using an OpenFlow switch.

Unified Core Network vs. Common SDN deployment

Common NFV/SDN implementations rely on virtualizing the EPC, so that the functions of the MME (Mobility Management Entity), the SGW (Serving Gateway), and the PGW (Packet Data Network Gateway) are each implemented in software and run on the same hardware. Drawbacks of this approach include:

  • the separation between the control and user plane is achieved by means of a switch, usually hardware-based and external to the network. This is a limitation of software-defined network functions;
  • the switch is designed to replace the PGW and obtain the IP connection which it sends to the eNodeB over the user plane. This means that it must support both GTP protocol for the user plane and IP which determines the high costs for such equipment.
  • the complexity of NFV requires additional effort from the network to accommodate it, which increases the overall cost of the solution.

The implementation of YateUCN differs significantly from the above.

First, it uses commodity hardware, so no special-purpose equipment needs is needed. Simply put, YateUCN is a COTS server, which completely diminishes investment, staff, space, and power requirements.

Secondly, YateUCN differs from virtualized EPC because it implements a unique software, based on Yate, that performs all functions of the MME, SGW, and PGW. All-software implementation also means that multiple protocols (Diameter, SS7) are equally implemented in YateUCN, and no additional implementations are required for the core to connect to the Home Subscriber Server or IMS. This helps operators cut down on highly specialized staff needs and facilitates inter-working with legacy networks.

Thirdly, instead of using a hardware switch, YateUCN implements it in the Yate kernel. Because the Unified Core Network is based on Yate, an expandable Linux-based telephony engine, it was possible to integrate a software switch in the core software, allowing for much faster data processing and eliminating the need to work with multiple vendors.

YateUCN core network solution removes the barriers of entering the market due to simplicity, scalability and low cost. YateUCN specifications features and specifications list can be accessed here.

The challenges behind VoLTE

In previous blog posts and demos we showed that a simplified approach is the way to obtain clear results in deploying VoLTE and 2G/4G mixed networks. We performed the industry’s first VoLTE call from a GSM mobile phone to an iPhone 6, through a single unified core network, the YateUCN, and we presented our solution for handling SRVCC (Single Radio Voice Call Continuity) as an inter-MSC (Mobile Switching Center) handover from 4G to 2G in the same YateUCN. Follow our take on why VoLTE hasn’t developed as rapidly as we all expected it would. We’ll give our insight and what we’ve learned from the many discussion we’ve had with mobile operators and smartphone producers alike.

Sure, VoLTE is great! Combining the powers of IMS and LTE, VoLTE offers excellent high-definition voice calls. It also guarantees a Quality of Service component, ensuring that customers get an unprecedented quality of voice services. However, VoLTE depends on far too many aspects to be fully functional and widely deployed, contrary to what optimistic reports have predicted in the past.

volte_issues

One of the main issues operators and customers alike are facing is the fact that there’s still a shortage of VoLTE capable smartphones. By April 2015 Verizon offered around 15 devices supporting VoLTE, while AT&T’s smartphone selection included around 19 devices capable of HD voice, in July 2015, as seen on their online shop. iPhone6 is still the only device capable of supporting VoLTE for all the operators that offer it. What’s more, most of these devices came from about 5 smartphone vendors, giving customers a limited choice when they buy a new phone.

Approximately 97% of VoLTE capable smartphones have their LTE chipset from the same vendor. According to reports from smartphone producers and operators alike, the VoLTE client is not stable enough, this being the reason why some vendors don’t even activate VoLTE in the baseband, and also why operators implement VoLTE in both the smartphones and the IMS network itself differently.

This also leads to the lack of interoperability between mobile carriers. Currently, VoLTE works only between devices belonging to the same network: for example, a T-Mobile customer using a VoLTE capable handset cannot roam in the AT&T VoLTE network of a called party. However, this was one of the main goals when VoLTE specifications were developed and we should still expect it to happen at some point.

Lastly, and perhaps most importantly, VoLTE deployments are scarce. A GSA report from July 2015 showed that only 25 operators have commercially launched VoLTE networks in 16 countries, while there are around 103 operators in 49 countries who are planning, trialling or deploying VoLTE. Compared with the total of 422 LTE networks commercially launched in 143 countries, VoLTE deployments are dramatically lower. This is the result of mobile carriers having a difficult time planing and building functional LTE and VoLTE networks, while also developing the essential Single Radio Voice Call Continuity (SRVCC) technology in an effective and performable way.

VoLTE still needs to leap over many hurdles until it becomes a technology used world wide. Operators, network equipment vendors, smartphones and chipset producers need to cooperate and jointly find technical solutions that will allow for a more swift VoLTE roll-out in most LTE networks.

Extending LTE networks the easy way

We’ve often stated that YateUCN, our unified 2G/4G core network solution, can be used to extend existing LTE networks or upgrade GSM deployments to 4G LTE. And that’s correct. In this post we will take a closer look at how that happens and why YateUCN is more profitable than current solutions for operators moving towards LTE networks.

YateUCN is designed as a unified equipment that replaces all the functions performed by separate hardware components with one software application running on commodity hardware. This has the advantages of reducing the infrastructure costs, minimizing the equipment’s time to market, and increasing network resiliency due to a simplified management of software.

Let’s look at two scenarios where YateUCN can be integrated in existing networks.

Extend 4G LTE networks

For operators looking to increase access to 4G services YateUCN is a flexible, cost-effective solution. It drastically reduces initial equipment investment, allowing them to roll out more networks in a shorter time, to better serve growing consumer needs.

This can be done easily because YateUCN integrates all the LTE-specific functions and protocols, so that it interconnects with any existing operator setup. Every hardware component in the EPC – the MME, SGW, PGW, PCRF, and PCEF – is replaced with software running on a single piece of equipment.

The MME function handles UEs trying to connect to the network. It is responsible for subscriber authentication and uses S6a interface (Diameter) to connect to the operator’s HSS. The MME is also in charge of mobility management, allowing UEs continuous connectivity and active sessions as they move through the network.

YateUCN is fully compatible with any eNodeB, using S1-AP interface to manage inter-MME handover.

The SGW function allows YateUCN to manage data traffic routing over S1-U interface, ensuring communication between the eNodeB and the PGW, which establishes and maintains the IP session. The PGW interconnects with the charging solution of the operator using Diameter and Radius interface, allowing AAA management for wireless access.

The PCRF in YateUCN maintains QoS levels and charging policies, enabling mobile operators to control bandwidth usage while their subscribers are roaming. The Policy and Control Enforcement Function, PCEF, performs policy enforcement and service data flow detection, making sure the data flow through from the PGW is accessible.

The unified nature of YateUCN leads to large equipment savings, and makes it easy to manage the network capacities with a software upgrade.

Upgrade networks to 4G LTE

2G/3G networks can be upgraded to 4G LTE using YateUCN core network and SatSite for the radio network. A new LTE network with YateUCN and YateENB SatSite significantly reduces overall network roll-out costs. SatSite operating on YateENB is an eNodeB communicating with the MME in YateUCN over S1 interface and with any other eNodeB over X2 interface.

Since YateUCN also unifies all the layers of the GSM/GPRS core alongside the EPC, it also acts as an extension of existing 2G networks, achieved at no costs for additional 2G core equipment.

SatSite can run on YateBTS and YateENB at the same time, so each cell will act as a mixed 2G/4G site. As a result, operators can choose to use SatSite in mixed 2G/4G networks, without needing a new 2G core. What’s more, since in 2G mode YateBTS SatSite unifies both the BTS and the BSC layer, it communicates directly with YateUCN core network, using the SIP/GTP protocols.

The MSC contained in YateUCN allows subscribers to be handed over from the YateUCN – SatSite network to the operator’s current 2G deployment in the case of CS services mobility. Subscribers can roam from the YateUCN/SatSite network to any existing MSC serving the roaming area to ensure voice services continuity.

YateUCN can be integrated in any system already deployed by the operator. Used together with SatSite, it serves to build complete 4G LTE or mixed 2G/LTE networks with a low infrastructure and operations investment, ensuring consumers consistent access to both voice and data services.

Rethinking redundancy: a new approach to core networks

Mobile communications must provide uninterrupted mobile service at all times, but the costs to create network redundancy with current conventional equipment are restrictive. YateUCN unified core is a profitable and flexible solution for redundancy in 2G and 4G mobile networks.

Network redundancy ensures that as technology advances, the capacity of network infrastructures to support more subscribers without blackouts adapts accordingly. YateUCN is a unified core network allowing resiliency in 2G/LTE mobile networks using YateBTS and YateENB SatSite. SatSite acts as a BTS/BSC communicating directly with the MSC/VLR/SGSN/GGSN and EPC in YateUCN.

As a software-defined core solution, YateUCN replaces the heavy, expensive core equipment used in conventional networks with smaller, affordable, and easy-to-manage equipment. It is a software implementation of 2G and LTE core network layers, operating on commodity hardware.

yucn_redund_2015-7-16_draft4.2_pic2

In typical networks, redundancy is achieved by supplying an additional core server for any given core server, causing costs to more than double, since supplementary costs for the configuration of back-up servers add up to the capital expenses.

YateUCN implements the core network functions and protocols in software, enabling any other YateUCN node to take over extra-traffic in case of failure of a node, or if the network capacity needs to be increased.

While conventional MSC/VLR in data centers are limited to serving a given number of BSCs in a defined geographical area, in a YateUCN – SatSite network the base station allows a device to connect to any YateUCN node in the network, irrespectively of the geographical location of the device/BTS and of whether the network is 2G or 4G. A list of available YateUCN units is configured in each YateBTS/YateENB SatSite.

Core equipment is usually designed to allocate specific core network functions (authentication, mobility, call setup, data routing) to separate nodes. Such equipment is heavy due to the large number of components, increases lead time, and requires separate back-up equipment for each node.

YateUCN unifies both GSM and LTE core layers, meaning that a single alternate YateUCN server provides full redundancy for any other server in the network. If a failover should occur in a YateUCN node, a device can register to a different YateUCN, remaining attached to the same base station, as shown below.

yucn_redund_2015-7-15_draft4.1

A new YateUCN is chosen from the list of YateUCN units held in the base station. If a mobile device remains connected to the same BTS, registration to the MSC/VLR in the new YateUCN is performed whenever the device communicates with the network to perform an action. Registration to the new YateUCN is updated in the HSS/HLR.

If the device roams to an area served by a different BTS, they will connect to the new SatSite, but will remain connected to the YateUCN currently serving it, and a new query in the HLR is not required. This reduces the load on the HLR and allows it to support a higher subscriber capacity. This can be seen below:

MS connecting to a new YateUCN

MS connecting to a new YateUCN

Increasing traffic to a YateUCN core server is easily performed because YateUCN communicates with 2G base stations using SIP and GTP, and with eNodeBs over SIP/S1AP/GTP. SIP and GTP signalling protocols have the advantage of scalability and interoperability, allowing different service requirements to be served at the same time and with the same quality standards.

Because YateUCN uses commodity hardware, operation and servicing can be managed remotely, with minimal external support, significantly driving operational costs down. YateUCN provides simplicity and cost-effectiveness to building redundancy in mobile networks so that operators can provide high-quality service at all times.