IPRAN

What Is an IPRAN?

An IP Radio Access Network (IPRAN) is a wireless access network that utilizes IP/MPLS at the metro aggregation/core layer and Layer 2 enhanced Ethernet at the access layer. It is a combined router/switch solution tailored for IP-based base station backhaul scenarios. In recent years, IP-based networks, including IP-based mobile transport networks, have become a prominent trend in carrier network development. However, traditional solutions are inadequate to meet future data transportation needs. Therefore, IPRAN is proposed as the most direct solution for IP-based wireless access and is now widely adopted.

Why Is IPRAN Necessary?

A Radio Access Network (RAN), also known as a base station backhaul network, is a transport network deployed between base stations and base station controllers.

Traditional RANs of mobile carriers are built using Time Division Multiplexing (TDM)/Synchronous Digital Hierarchy (SDH). However, SDH, based on TDM, provides only rigid pipes with low bandwidth utilization, suitable only for 2G audio and text information transmission.

To accommodate services like Asynchronous Transfer Mode (ATM) and Ethernet, SDH-based Multi-Service Transport Platform (MSTP) networks are widely used. MSTP-based networks allow concurrent access, processing, and transmission of TDM, ATM, Ethernet, and other services, managed in a unified manner. Yet, their traffic transmission is based on rigid TDM pipes, making it challenging to provide the high bandwidth needed for 3G services.

While an ATM Packet Switched Network (PSN) can improve bandwidth utilization, its complexity in deployment and operation hinders widespread adoption. In contrast, traditional connection-oriented IP networks are easy to deploy and cost-effective but cannot guarantee quality and performance for important services, unsuitable for carrier-class transport. In this context, IPRAN emerges as the next-generation transmission technology, focusing on packet management data transmission and shifting from audio to data and multimedia support, ushering RANs into the IP transport era.

Built on traditional IP networks, the IPRAN mobile transport solution integrates Operations, Administration, and Maintenance (OAM) and Quality of Service (QoS) mechanisms to address wireless backhaul needs. Besides providing IP connectivity between base stations and base station controllers, this solution is compatible with various transmission media. IPRAN combines SDH and IP network advantages, offering carriers a flexible, reliable, and cost-effective base station backhaul network solution.

How Will IPRAN Evolve?

To meet the transport requirements of 5G and build next-generation intelligent transport networks, IPRAN will adopt Segment Routing over IPv6 (SRv6) and Ethernet Virtual Private Network (EVPN) as fundamental protocols, FlexE for network slicing, and IFIT for network O&M.

EVPN leverages BGP extensions to move MAC address learning and advertisement between Layer 2 networks from the data plane to the control plane. This unification of the control planes of L2VPN and L3VPN reduces the need for full-mesh connections and traffic broadcasting, minimizing device resource wastage.

FlexE inserts a FlexE shim layer between the physical and data link layers of the OSI model, separating the physical layer from the data link layer. This allows an intelligent transport network to achieve flexible hard slices, eliminating port congestion and enabling hard bandwidth isolation and differentiated connections.

SRv6 serves as a core forwarding protocol for intelligent transport networks, offering high programmability and flexibility. It translates network-carried services into a series of forwarding instructions sent to network devices along the forwarding path, enabling service customization through network programming. SRv6 boasts advantages such as an almost limitless address space, network-wide unique node identification, and reachability to any node.

IFIT supplements real service packets with IFIT packet headers to measure network performance. It reports measurement data in real-time via telemetry, achieving in-band flow measurement in milliseconds. With telemetry-based reporting and iMaster NCE-based intelligent analysis, IFIT can measure service SLAs in real-time. In the event of a fault, IFIT can demarcate and locate the fault within minutes, enabling rapid service recovery. IFIT offers benefits like high precision, easy deployment, proactive O&M, and visualization.

Empowered by these innovations, intelligent transport networks will deliver increased transport efficiency, enhanced SLA assurance, and accelerated service provisioning, meeting the transport network demands of emerging services like 5G.

Applications of IPRAN

The IPRAN solution is a specialized integrated router/switch solution designed for IP-based base station backhaul scenarios. Currently, two widely used derivatives are mixed VPN (L2VPN + L3VPN) and hierarchical VPN.

In the mixed VPN (L2VPN + L3VPN) solution, L2VPN is deployed on the access side, and L3VPN is deployed on the aggregation side. This configuration isolates faults from each other, improving the overall network robustness and enabling large-scale dynamic networking.

On the other hand, the hierarchical VPN solution uses hierarchical L3VPN to isolate faults from each other. This approach results in a network that is relatively robust, reliable, secure, and easy to maintain.