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.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s