What is Passive, Active and Backhaul Sharing?

Few weeks ago, Potraz and Telone jointly hosted an infrastructure sharing symposium, where directors and CEOs of telecoms companies converged at a local lodge in Harare to deliberate on the possible ways of sharing infrastructure. The dialogue focused on both passive and active sharing. This article will look into the meaning of the two terms, passive and active sharing.

By Tongai Mwenje

Telecoms infrastructure for operators primarily consists of:

• Active infrastructure (such as spectrum, switches, antennae)
• Passive infrastructure (such as towers, BTS shelters, power)
• Backhaul.


Core network elements such as switching centres, GPRS service nodes, transmission equipment and all links connecting elements of the core network.

Passive sharing (commonly referred to as tower sharing) is usually defined as the sharing of space or physical supporting infrastructure which does not require active operational co-ordination between network operators. Site and mast sharing are considered to be forms of passive sharing.

As a general rule in the cellular industry, passive infrastructure sharing encompasses all the non-electronic elements required of a cell site. These can include: the tower itself, buildings or shelter, air conditioning plant, security, electricity generation capability for back-up, an electrical supply, technical premises and pylons.

Active infrastructure sharing is where companies share electronic infrastructure. The examples have been given above.

The table above also depicts a list of examples that fall under active sharing. These are considered forms of active sharing as they require operators to share elements of the active network layer including, for example, radio access nodes and transmission. For RAN sharing, MNOs continue to keep separate logical networks and the degree of operational co-ordination is less than for other types of active sharing.

Network sharing across these categories may include a number of parties. Whilst there may be significant commercial and practical hurdles to overcome, there are no fundamental reasons why multiple operators cannot share networks. For example, up to six operators share a single site in India. Agreements may concern individual sites, a number of sites or particular regions.

Passive sharing and RAN sharing do not require a fully merged network architecture and there are examples of unilateral, bilateral (mutual access) or multilateral agreements.

Backhaul, a term probably derived from the trucking industry, has several usages in information technology.

In satellite communication, backhaul is used to mean getting data to a point from which it can be distributed over a network. For example, to deliver a live television program from one city to authorized DirecPC satellite terminals around the country, the video signals would have to be backhauled by some means (by optical fiber cable or by another satellite system) to the Hughes DirecPC facility in another city.

From there, it would be uplinked to a certain satellite point from which DirecPC users could view the broadcast (receive it in a downlink from the satellite at their individual terminals). Backhauling is also used to get non-live audio and video material to distribution points at the major broadcast news organizations for broadcast in the evening or ongoing news.

Manufacturers of network switching equipment use the term to mean “getting data to the network backbone” (which is similar to its use in the satellite communication industry). For example, Ascend uses the term to describe how its MAX 2000 switch can be used to interconnect data from a backhaul T-1 line on which mobile and remote office users are connected to an Internet service provider and the backbone of the Internet.

According to books we like, backhauling is sending network data over an out-of-the-way route (including taking it farther than its destination) in order to get the data there sooner or because it costs less. This kind of backhauling involves understanding changing network conditions and economics.

Backhauling may sometimes be used to mean the use of the back channel on a bidirectional communications line.

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