FTTH Architecture P2P and PON

FTTH (Fiber To The Home) has changed a lot in the way we live and work. When planning an installation, many factors should be taken into consideration, such as regulation, implementation cost, the need to future-proof investment and so on. This blog will mainly focus on two main FTTH architectures–point to point (P2P) and passive optical network (PON) as one of the suggestions for FTTH deployment.

 

Why Need FTTH Deployment?

Currently, the requirements for higher internet access speeds are increasing by various applications, such as cable TV, Movie Streaming, Multi player Gaming, Video Conferencing, 3D, etc. Apparently the transmission capacity of copper cables is limited and can’t meet the the needs of higher bandwidth. So fiber cables soon become the substitutes of copper cables. FTTH technology uses optical fiber cable from a central point directly to individual buildings such as residences, apartment buildings and businesses to provide unprecedented high-speed Internet access. FTTH dramatically improves the network speeds available to computer users compared with technologies now used in most places.

 

What Are P2P and PON?

Before deploying FTTH networks, let’s take a look at two main FTTH infrastructure types P2P and PON. In short, P2P architecture uses all active components throughout the chain & point to multi-point (P2M) and PON architecture uses passive optical splitters at the aggregation layer.

 

In a PON network architecture, an optical line terminal (OLT) will be deployed in the Point of Presence (POP) or central office. One fiber cable connects the passive optical splitter and the fan-outs connect end users (a maximum of 64) with each one having an Optical Networking Unit (ONU) at the point where the fiber cable terminates.

 

While a P2P architecture is more complex. It has a core switch at the central office, which connects over optical fiber cables to an aggregation switch at the distribution point (typically located at a street corner). These aggregation switches have many fiber ports and each port directly connects to an Optical Network Termination (ONT), which is located inside or outside the user’s residence or business premises.

 

Advantages and Disadvantages of P2P and PON

To decide which kind of architecture to choose, more details should be known. Each type has its own advantages and disadvantages. The following will list the strengths and weaknesses to make the decision.

 

Advantages of P2P

First, each port of the aggregation switch is dedicated to individual users. So there is no sharing. It means each port can get higher bandwidth.

Second, P2P provides symmetrical bandwidth, with identical upload and download capacity. That’s quite important to the applications, for example, HD video conferencing and peer-to-peer file sharing, etc.

P2P is a standard technology and the bandwidth of each port can be set or controlled. Therefore, users can get the bandwidth as they require.

P2P can reach longer signals transmission distance with fiber cable, maybe more than 100 km.

It’s easier to locate and troubleshoot the fault over P2P network line with an OTDR (Optical Time Domain Reflectometer).

P2P is future-proofed for it can be upgraded with the bandwidth and capacity growing.

Disadvantages of P2P

P2P increases more costs since this architecture need more components.

P2P requires longer rollout time as it needs more street cabinets than PON. And that can also lead to higher capital expenditure.

Advantages of PON

PON network spends less than P2P for implementation and maintenance. Because it uses fewer active ports to terminated fiber and needs fewer fiber cables.

The passive fiber optical splitters don’t need power supply, so they can be located anywhere in the field according to the project requirements. It’s more flexible.

As the architecture is is not as complex as P2P, so it would be easier and faster for the PON network infrastructure deployment.

With encryption, each connection of PON has higher security.

PON gives considerably high downstream bandwidth and low upstream bandwidth similar to current broadband technologies. For instance, GPON can deliver up to 2.5 Gbps of downstream bandwidth and 1 Gbps of upstream bandwidth which shall be shared by 32 or 64 users.

Disadvantages of PON

The bandwidth offered by PON infrastructure is limited because the bandwidth is shared by multiple subscribers.

The bandwidth is asymmetric. The download capacity is much greater than the upload one.

It’s more difficult to upgrade a PON network once it’s implemented, especially when the bandwidth requirements change.

As optical splitters have both bandwidth limitations (particularly upstream) and cause high attenuation losses, they are likely to be out of data compared with a P2P architecture.

Summary

The above content shows information about the advantages and disadvantages of FTTH P2P and PON architectures. When designing the architectures, network operators should balance the strengths and weaknesses of both types. If you need a future-proof infrastructure, you better select P2P. Besides, cost and network efficiency are also the factors to decide which architecture is more suitable. Actually, architectures design may depend on many other situations. Hope this article is helpful for you.