In order to support a Whole-of government (“WOG”) initiative to minimize land use and road opening, developing agencies (“DAs”) (i.e., MND, URA, HDB, JTC and LTA) will adopt a Common Service Duct (“CSD”) model to house utilities together for greenfield/new developments (where applicable). FBOs that are licensed to deploy underground telecommunication infrastructure shall refer to the below summary of the CSD Framework.

CSD is a common set of ducts and manholes that may be singly or jointly built, owned and maintained by Public Telecommunication Licensees, designated to serve an area where access or road openings are limited. CSDs are designated for shared use by multiple Facilities-based Licensees to house telecommunication cables for the deployment of telecommunication networks.

Summary of CSD Framework

A summary of the CSD framework regulated under the Code of Practice for Competition in the Provision of Telecommunication and Media Services (the “Code”) is set out below.


Item Description

Summary of CSD Framework


CSD Ownership

IMDA will designate a Public Telecommunication Licensee (“PTLs”) to be the CSD owner and operator (“Designated CSD Owner”). IMDA has designated NetLink Trust (“NLT”) for this role in view that NLT is the neutral passive infrastructure network operator who has the obligation to lease the passive infrastructure at wholesale, non-discriminatory and cost-based terms to any licensee. 

Where there are unique requirements such as CSDs for submarine cable deployment, and when other PTLs have more experience, expertise and direct interest in such infrastructure, IMDA may consider designating other PTLs to be the CSD owner and operator instead. 

The Designated CSD Owner, will also own and manage the manholes which are needed to access the CSDs and to provide connection ducts for FBOs (including CSD co-owners) to connect their ducts to the CSD manholes.


CSD Co-Ownership

All other PTLs may choose to be co-owner(s) of the ducts. In the event that PTLs choose not to co-own the ducts, they may lease the ducts from the Designated CSD Owner just like any other FBOs. 


Operations and Maintenance (“O&M”)

For Manhole – The Designated CSD Owner shall be fully responsible for the O&M of the manholes.

For Duct – The Designated CSD Owner and co-owner(s), if any, shall maintain its own ducts or may jointly appoint a single party to maintain them.


Capacity Forecast and Planning

Designated CSD Owner’s Own Committed Ducts

The Designated CSD Owner’s own Committed Ducts are for deployment of its own cables to provide telecommunication services.

Additional set-aside ducts by Designated CSD Owner for FBOs

The Designated CSD Owner shall set aside additional duct capacity of no less than 20% of its own duct requirement, for leasing to FBOs (“Set-aside Duct”). 

FBO’s Committed Ducts during Designated CSD Owner’s Polling

During the CSD planning stage, FBOs who are interested to lease ducts on a long-term basis shall provide their committed duct forecast to the Designated CSD Owner during the poll (“Committed Duct”). FBOs are expected to plan their committed duct projections based on their own needs to provide telecommunication services to the area(s) served by the CSDs. If the FBO is not prepared to commit to the number of ducts, the FBO shall make its intention clear during the poll and the Designated CSD Owner may choose not to include them in the capacity planning. Under such instance, these FBOs can approach the Designated CSD Owner to lease duct space under the Set-aside Duct by the Designated CSD Owner, or lease fibre connections from NetLink Trust.


Lease Offer



FBOs should first approach the CSD Owner for CSD services.

Lease by Designated CSD Owner

CSD is designated as an Essential Support Facility under Interconnection Related Services under the Code. The Designated CSD Owner shall offer the following CSD services through a Reference Interconnection Offer pursuant to Section 6 of the Code[1]:

For Manhole – The CSD owner shall provide access to other FBOs via a cost-based regulated service offering.

For Committed Duct – The Designated CSD Owner shall offer long term lease of the ducts that are committed by the FBOs via a cost-based regulated service offering.

For Set-aside Duct[2] – The Designated CSD Owner shall offer duct space on short term lease (with provision to renew) via a cost-based regulated service offering. If there is interest for a longer lease term, FBOs may negotiate a customised agreement in good faith with the CSD owner for this requirement. For any subsequent request(s) for long term duct lease from any FBOs (including new entrants), subject to availability of Set-aside Duct capacity, the Designated CSD Owner and the FBO are to negotiate a customised agreement in good faith. To the extent possible, the Designated CSD Owner should ensure that FBOs do not hoard CSD duct capacity through the lease agreements for the Set-aside Ducts. 

For Connection Duct – The Designated CSD Owner shall offer connection ducts for FBOs (including CSD co-owners) to connect their ducts to the CSD manholes via a cost-based regulated service offering.  

In the event that the Designated CSD Owner’s Committed Duct capacity is fully utilised and requires more duct capacity to provide its own telecommunication services, the Designated CSD Owner may utilise the available Set-aside Duct capacity[3], but subject to IMDA’s prior approval. The Designated CSD Owner would have to prove that it has done due diligence in its demand projection and has fully utilised its own ducts in its request to use the Set-aside Duct capacity.  

Sharing by CSD co-owner(s)

CSD is also designated as a Critical Support Infrastructure and an infrastructure to be shared under the Code.  

In the event that there are no available ducts for lease by the CSD owner, CSD co-owners will be required to share their available duct capacity[4], upon request, at cost-based prices and non-discriminatory terms and conditions.  As CSD co-owner(s) had planned its duct projections based on its own needs only, there is no requirement for CSD co-owner(s) to share its available duct capacity if there is still available duct capacity for leasing by the Designated CSD Owner. 

As provided for under the Code, the sharing will be based on voluntary negotiation between the CSD co-owner and the FBO. In the event where voluntary negotiation fails, the parties may raise the dispute to IMDA for resolution. 

Under the sharing of CSD duct capacity, to the extent possible, CSD co-owner(s) should ensure that FBOs do not hoard CSD ducts through its sharing agreement.

Sub-leasing by FBOs

FBOs should explore leasing fibre connections from NetLink Trust if there are no available CSD duct capacity for lease. FBOs should only approach other FBOs for sub-leasing only under exceptional circumstances, e.g., when leasing of fibre connections is not suitable or possible.

FBOs shall seek IMDA’s prior approval if they choose to sub-lease their unused duct capacity that was leased from the Designated CSO Owner to other FBOs to ensure efficient use of duct resources. 

CSD Co-owner(s) can decide if they will allow sub-leasing of their duct capacity in the sharing agreement.


Cost Allocation

Construction costs of the ducts (including the trenching cost and all associated costs for the CSD, not attributable to the manholes) shall be allocated according to the proportion of ducts owned by the Designated CSD Owner and the co-owner(s).


Forward Planning

If the overall demand outstrips the planned supply for the CSD, IMDA will work with the industry and the relevant government agencies to expand the CSDs or plan for new CSDs to be built before the supply runs out.

List of current CSD Projects

Please refer to the below list of current CSD Projects and ownership details:

Current CSD Projects [as of 17 Mar 2022]



Designated CSD Owner




NetLink Trust

Singtel and StarHub


Marina South

NetLink Trust

Singtel and StarHub

[1] For the case of NLT, the Reference Interconnection Offer will be in the form of an Interconnection Offer (“ICO”) Schedule.

[2]The Set-aside Duct capacity is mainly to cater to demand by FBOs who would like to lease on a short-term basis, or latecomers or new FBOs who missed the polling stage and did not put in their demand.

[3] This would be similar to the other PTLs who are co-owners or FBOs have committed long-term lease in the CSD.

[4]There is no requirement on lease term. CSD co-owners may share ducts or duct space depending on FBO’s request and CSD co-owner’s availability.

Last updated on: 10 May 2022

Explore more