Slicing as a Service

Converged transport of 5G vertical industrial applications is a evolutionary trend of the future transport network, while network slicing is one of the keys to achieve the goal. Every slicing application occupies certain network resource to meet their own KPIs, such as bandwidth, isolation, low latency, large number of connections, high-precision time synchronization for IoT (Internet of Things) etc. with network programmable capability. Slicing is a kind of service, which was firstly proposed by the 5G core network, and later extended to the transport network and radio access network.

A new Infrastructure

The traditional transport network cannot meet such requirements any more, so the future transport network should be based in a converged infrastructure to provide capabilities of transporting different slice applications on the same transport network .

ZTE’s converged transport solution is such a converged infrastructure with the following features:

Better Performance, Lower Cost, and Easier O&M

This solution meets large bandwidth by integrating Flexible Ethernet (FlexE) Bonding with Ethernet-based Dense Wavelength Division multiplexing (DWDM) . It can decouple Ethernet PHY from MAC for smooth bandwidth upgrade and direct Ethernet signal optical layer mapping without traditional optical wavelength conversion, thereby greatly reducing cost and power consumption .

The large number of connections is achieved by Segment Routing (SR) standardized by IETF, Being a kind of source routing technology, it can save the consumption of distributed control plane computing resources. In addition, it has the advanced functions of Internal Gateway Protocol (IGP) fast convergence, SR micro-loop avoidance and Segment Routing Transport Profile (SR-TP). IGP fast convergence and SR micro-loop can break through the limitation of the IGP domain size (by managing more than 1000 network elements) in the networking planning and greatly reduces the network O&M complexity. SR-TP can provides the transport network OAM features similar to SDH mechanism, ensuring high-reliability connections with bidirectional service failure recovery time in less than 50ms, further simplifying control of connections and improving the network scalability.

Slice Isolation Offers KPI Guarantee

The solution provides hierarchical slicing services based on Service-Level Agreement (SLA), including hard isolation and soft isolation. FlexE is used to implement hard isolation by using time division multiplexing mechanism among FlexE clients. SR extension is used to implement soft isolation.

Ultra-low Latency

The solution achieves low latency on the Ethernet layer, using time division multiplexing structure of FlexE shim layer. It makes one (some) time slot(s) inbound to cross connect one (some) time slot(s) outbound on single network element, and we name it as Ethernet layer cross connect. It can not only reach transmission delay of 0.5us per node, but also achieve network-level low latency due to connection-oriented feature, so that improving uRLLC service coverage radius, saving investments of MEC deployment.

High-precision Synchronization

Besides, The transmission of time synchronization on the ground has to be used at some places where there is no GPS coverage. This solution can greatly improve the time synchronization quality with single-fiber bidirectional, high-precision time-stamp and zero-latency phase-locked loop, so that making the high-precision positioning service possible in places without GPS coverage.

Positive Practice

The characteristics of converged transport solution has been proved together with many Tier 1 operators in prototype tests, field trials, and joint demonstrations on many well-known telecommunication exhibitions. ZTE has implemented low latency and high-precision synchronization lab verification with China Mobile in 2017. Besides, ZTE has firstly demonstrated low latency feature at Mobile World Congress 2017 in Barcelona.

High Praise from Third Parties

In addition, this solution has won high ratings from well-known consulting organizations due to its advanced performance and forwarding-looking philosophy. In October 2018, GlobalData, a well-known telecommunications, software and IT services consulting company, released the report on 5G Review of 5G technology readiness and commercialization. ZTE received the highest rating of “Established Player” in 5G transport network technology. ZTE was named one of the four major suppliers in the 5G Transport field.