BIG-IP Carrier-Grade Network Address Translation (CGNAT)




Adaptive TCP Optimization

Efficient RAN (Radio Access Network) Utilization

Fast Video reproduction

Blazing fast website browsing

Scale and Speed


High bandwidth requirements

Protection from DNS Tunneling

Enhance traffic management

IPv6 migration

OTE Group, the largest technology company in Greece, under the brand name COSMOTE provides a plethora of telecommunications services such as fixed, mobile telephony, broadband access, pay-TV as well as integrated ICT services in the business world. The company had to find ways to make better use of its existing infrastructure by constantly improving the customer experience.


Business Challenges

OTEgroup constantly invests in infrastructure and new technologies in order to improve the customer experience and the coverage it has in the telecommunication services. With these investments creates the infrastructure for the Gigabit Society of the future.

COSMOTE mobile network is the largest mobile network in Greece, winning 8 times the award for the fastest network of the Speedtest AwardsTM organized by Ookla. The 4G coverage of COSMOTE network exceeds 99% and is by far the No.1 in Greece. At the same time COSMOTE introduced 5G services, being the first company to introduce 5G commercially in Greece. Today the coverage of its network in 5G services exceeds 50%.

The constant increase of subscribers, but also their need to access applications and content with high bandwidth requirements, has led to a geometric increase in the volume of data transmitting through the COSMOTE mobile network. Just think, only in recent years, how many over the top (OTT) services and how many social media applications have appeared and gained the interest of the customers.

“So we had to find ways to make better use of our existing infrastructure by constantly improving the customer experience. The mobile Internet experience of COSMOTE customers goes through two different worlds: that of the Radio network and that of the Core IP network. And there are many different features between them” mentioned Michalis Papamichael, Director of Core Network Devops & Technology Strategy of OTE Group.


The BIG-IP solution of F5 was the best choice for COSMOTE! “It is worth noting that the improvement we noticed when we routed all the traffic through the F5 system was close to 9%, a very large percentage for a provider of our size. Since then, we are constantly measuring and optimizing, because our network, applications and mobile devices are constantly evolving” noted Michalis Papamichael, Director of Core Network Devops & Technology Strategy of OTE Group.

The fact that all the subscribers’ data traffic passes through F5’s BIG-IP, makes it an ideal point for further traffic management. The topology, layout and capabilities of F5’s BIG-IP opens the way to think of solutions aimed at optimizing the quality of services, but also the integration of new ones. “We are constantly in discussions with Pylones Hellas which is the local partner of F5, but also with F5 directly and we analyze needs and use cases, while there are numerous PoCs that we have done all these years of our cooperation.” “said Michalis Papamichael, Director of Core Network Devops & Technology Strategy of OTE Group.

One of the upcoming plans of COSMOTE is to optimize QUIC traffic, which has been growing steadily in recent years, especially in terms of Video Streaming. QUIC is based on the UDP protocol and F5 Networks supports rate-pace in UDP traffic as it does with TCP, through dynamic methods!

Another project concerns the company is the DNS protocol and in particular the protection of our network from DNS Tunneling cases, while at the same time, the company is considering the interconnection of the BIG-IP system with the PCRF, in order to have the possibility of personalized traffic management at subscriber level.

In other words, imagine that COSMOTE will be able to know the Radio type of each subscriber (4/5G) at any time and apply special optimization algorithms.


Better User Experience

BIG-IP operates as an intermediate proxy between these two worlds and through proprietary algorithms, optimizes their interconnection,  as a result COSMOTE is always in the first place in the user experience, while at the same time makes the most of our internet infrastructure.

Ease IPv4 to IPv6 migration with a secure IP address strategy

The company decided F5 BIG-IP to take on the role of Carrier Grade NAT (CGNAT), ie the system that converts private IP addresses to public ones. In this way COSMOTE effectively deal with the depletion of IPv4 addresses. In its solutions the company also have IPv6 rapid deployment (6rd), giving the flexibility to activate it whenever necessary.

High-speed logging

COSMOTE achives a high-speed logging with IPFIX support that significantly reduces the volume of data per record. In this way, we COSMOTE is fully in line with Greek and European legislation regarding logging, while at the same time have limited its storage needs.

“Our cooperation with Pylones Hellas and F5 is nothing else but strategic and we hope to remain as efficient as it has been up to now.” says Michalis Papamichael, Director of Core Network Devops & Technology Strategy of OTE Group..