IPoC: A New Core Networking Protocol for 5G Networks

Greg White
Distinguished Technologist, Network Technologies

Oct 29, 2018

5G is the latest iteration of cellular network technology developed to meet the growing traffic demand for both smartphones and homes. With beamforming and frequency bands reaching millimeter waves, 5G promises many benefits:

  • Higher speeds
  • Lower latency
  • The ability to connect many more devices

However, current de jure standards and protocols, designed for earlier technologies, have the potential to dilute these promises. To address the limitations of current networks, CableLabs developed the IP over CCN (IPoC) protocol, a compelling new solution to meet the new, more robust requirements of 5G.

Why a New Solution?

The primary goal of the fourth generation (4G or LTE) technology was access to the Internet, so the technology utilized IP networking, the packet routing technology historically and currently used in the Internet.

IP networking has been around since the mid-1970s and has served us remarkably well, but it isn’t without flaws. The purpose of the Internet Protocol is to allow a computer at one fixed location in the network to exchange information with another computer at a fixed location in the network.  For mobile devices (that clearly aren’t at a fixed location) this has never been a great fit, and LTE technology had to develop complicated IP over IP tunneling mechanisms (the LTE Evolved Packet Core (EPC)) to enable mobility.

Furthermore, in the majority of cases, a mobile application wants to fetch specific data (say the text and images of a blog post) but doesn’t really care which computer it talks to in order to get it. As a result, to improve network efficiency and performance, network operators (both mobile and fixed) have implemented complex Content Distribution Networks in order to try to redirect the mobile application to the nearest server or cache that has the requested data.

In LTE-EPC, all of a user’s IP traffic is tunneled through a centralized choke point (or anchor) in the mobile operator’s core network, which eliminates the ability to serve data from a nearby cache. Also, as a mobile device moves in the network, the EPC needs to create new tunnels and tear down old ones in order to ensure that the user’s data reaches them.

These limitations are widely acknowledged by standards-setting groups. They are currently soliciting input to introduce new protocols that will pave the way for 5G to meet the demands of next-generation technologies, specifically:

  • Improve the efficiency and performance of the network mobility plane, compared to today’s LTE standards,
  • Support non-IP network protocols, of which Content Centric Networking is a leading candidate.

Benefits of Content Centric Networking

Content Centric Networking: A networking paradigm that emphasizes content by making it directly addressable and routable. Learn more here.

CCN offers several key advantages over IP networking:

  • It employs “stateful forwarding” which elegantly and efficiently supports information retrieval by mobile client devices without the need for tunneling or a location registration protocol
  • It addresses content directly rather than addressing end hosts, which means that it enables in-network caching, processing and intelligent packet forwarding, allowing it to excel in content retrieval optimization, allowing data to be easily retrieved from an on-path cache
  • It supports a client device using multiple network attachments (e.g., radio links) simultaneously, providing greater reliability and performance.
  • Its design meets the needs of large-data and IoT applications

For many new applications, CCN provides a much better fit for purpose than the Internet Protocol.

IP over CCN (IPoC): A New Way to Handle IP

In spite of the significant improvements Content Centric Networking offers over current IP networking, the reality is that all of today’s applications, both client and server, are built to use IP networking. We developed IPoC as the solution to this issue. IP over CCN (IPoC) protocol is a general-purpose tunneling protocol that enables delivery of IP traffic over a Content Centric Network (CCN) or a Named Data Network (NDN).

IPoC enables deployment of CCN as the core networking protocol for 5G, both for new, native CCN applications and as a mobility plane for existing IP applications, replacing the LTE-EPC. As a result, IPoC saves the IP investment and allows a full transition to the new CCN protocol.

With this approach:

  • Native CCN applications reap the benefits of tunnel-free anchorless networking, along with the latency and efficiency gains that come from in-network caching.
  • Existing IP-based applications can be supported with a mobility management solution that is simpler than the existing LTE-EPC. Gone are the special-purpose tunnel management functions that create and destroy tunnels as mobile devices move in the network.
  • The need for network slicing to accommodate both IP and CCN and the complications and overhead entailed in running two core networks in parallel are eliminated.

IPoC Performance in Mobile Networks

With the assistance of two PhD students from Colorado State University, we developed simulation models and conducted performance and efficiency testing of the protocol in comparison to LTE-EPC. In our simulation study, we implemented the IPoC protocol using the Named Data Networking (NDN) simulator ndnSim (which implements a CCN-like semantic) and used mobile communication as the driving example, comparing IPoC-over-NDN protocol performance against GTP-over-IP. We found that the protocol overhead and performance impact of IPoC is minimal, which makes it suitable for immediate deployment.  The report on this study includes links to the source code as well.

Want to Take a Closer Look?

IPoC can be best understood as a transition technology. Providing a shim layer and allowing CCN to act as a mobility plane for legacy IP applications, it accommodates the current protocol standards while opening the door for deployment of native CCN applications and the benefits they offer.

The 5G standardization project is seeking new mobility solutions for 5G, and we believe CCN and IPoC would be a great solution to address the needs. We have submitted a definition of the IPoC protocol as an Internet-Draft to the Internet Research Task Force (IRTF) Information Centric Networking Research Group. In addition, we have developed a proof-of-concept implementation of the IPoC protocol on Linux.

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