Direct Sales Line +44 (0)20 8286 6529
Home >  Data Centre Networking > Connecting Main Distribution Areas
Connecting Main Distribution Areas
To HDAs and Access Racks

From the UK’s MTP® Specialists


The terms main distribution area (MDA), horizontal distribution area (HDA) and equipment area (EA) are most commonly associated with a Core Aggregation Access three tier data centre network topology.

Complete Connect can provide a number of solutions to connect your Main, Horizontal and Equipment Distribution Areas. The solutions shown below use a combination of our 24 fibre MTP/LC cassettes mounted in both our 2U and 1U housing panels and also uses our MTP coupler / adapter plates mounted in the same panels.

They can be found via the MX Series Home Page

In the topology shown on this webpage, the Main Distribution Area (MDA) is shown connected to Equipment Areas (EAs) via a Horizontal Distribution Areas (HDAs).

MX Fibre System

MDAs, HDAs and Equipment Areas within a Core Aggregation Access Topology

Historically this has been the most common model used within enterprise networks and was adopted into data centres.

The main functions of each layer are typically as follows. The core layer provides two high-speed switches between the modules in the aggregation layer and connects externally. The aggregation layer is the L3 and L2 boundary. It consolidates L2 traffic and is the platform for network services. The access layer contains all servers and storage (or SAN).

The MX Series Fibre System has been widely used in Core/Aggregation/Access networks. The flexibility of the MX Series enables it to support the huge variations in network designs that are based on this topology and can offer a variety of ways to create main distribution areas, horizontal distribution areas and equipment distribution areas.

The ANSI/TIA standard 942-2005 is widely followed to create this type of network and the MX Series has components that enable connectivity at each point within this design

A multi-tier core/aggregation/access network is often created using a series of distribution areas that enable all switches to be connected to each other within the same tier as well as being connected vertically to switches in other tiers.
Diverse cable routing between distribution areas provides network resilience.
A separate Storage Area Network (SAN) can also be connected directly to the MDA via two diverse cable routes.
Core Aggregation Access
The physical layout of a multi-tier core/aggregation/access network is often created using a series of distribution areas based on the ANSI/TIA 942-2005 theoretical model.
The main distribution area (MDA) is often located physically separately from other parts of the network and has been commonly adopted as a starting point for these types of network designs.
Conversely horizontal distribution areas (HDAs) located at mid-row or end-of-row within the servers areas are too common. HDAs are then connected to the MDA via two diverse cable routes.
Talk with one of our experts…

Connecting the Main Distribution Area

Higher Fibre Port Density MDA to HDA (End-of-Row)

With capacity for 12 MX modules, this panel enables high density fibre ports for MDA (main distribution areas). This gives the ability to minimise rackspace requirements by housing multimode and singlemode ports next to each other.

The MX Series also allows the network manager to add Cat 6 and Cat 6a into the same panel as well as house network TAPS.

MX Xpress End of Row Distribution
MX Xpress - Low Density

Lower Fibre Port Density HDA (End-of-Row) to Equipment Area (Top-of-Rack)

The MX 1U housing panel is ideal for connecting equipment to your network within access / server racks. With 5 slots for MX modules, a range of connectivity options are available with the ability to mix multimode fibre, singlemode fibre, Cat6/6A, Cat7 and 40G/100G ports within the same panel.

Each 1U panel will present up to 60 LC fibre ports. 20 Cat6 / 6A or Cat 7 ports or 40 40G/100G ports. The MX Series also allows the network manager to house network TAPS within the same panel.

Adding 40G and 100G Ethernet Channels

As the demand for higher data rates is pushed closer to the access layer, 40G ports are required across the aggregation layer and within storage servers. The ability to add these ports on an on-demand basis whilst ensuring capacity for further deployment in the future is paramount. The MX Series introduces a number of components including 40G breakout cassettes and conversion cables to enable this migration.

Similarly, being able to run 40G over incumbent fibre infrastructure originally designed for 10G can help minimise disruption and reduce costs. Again, the MX Series offers products that can achieve this and will not become redundant as further 40G adoption takes place.

MX Xpress - with 40G

Example of MX Series Distribution

MDA connects to a HDA with up to 288 fibres (144 channels)
HDA feeds 24 fibres into up to 12 Equipment Areas (EAs)
The HDA can be housed in one of the 12 EAs or in a separate cabinet
MDA to HDA and EA fibre cabling can have a primary and a secondary route

Example of MX Series Distribution

Enabling LC connections in multimode and singlemode in all equipment cabinets
MDA or HDA can connect directly to SAN directors via MTP hydra cables (MTP – LC harnesses)
Different colour MTP adaptors for easier location designation
MDA or HDA can connect directly to SAN directors via MTP hydra cables (MTP – LC harnesses)
MX 1U loaded

Why Use An MTP Modular Cassette Solution?

Maximum use of rackspace

Each 1U panel can also hold 24 fibre cassettes and so other options include have a 72 LC fibre presentation with LC cross connects or a mix of LC and MTP connectivity in the HDA.

Easy roll out

Each HDA can support any number of equipment racks and is usually located at end of aisle or centre aisle and allows for diverse routing of primary and secondary cabling.
The cross connects within the HDA enable inter-aisle connectivity, ease of access and can reduce overall cabling distances. In the figure above the two HDAs are M310 1U MTP through coupler housing panels. Each one of these 1U panels offers up to 288 fibres (144 pairs).

Operational Benefits

Provides a high level of flexibility at all points for future MAC’s
Expanding the network to include additional cabinets becomes modular and straightforward
Easy upgrade path to 40GbE
Incorporate 40GbE along side the existing cabling, utilising the same housing panels
data centre fibre networking


+44 (0)20 8286 6529

Back to Top