The latest technology development direction of optical fiber access

Simpler, smarter, flatter

From DSL to fiber-optic homes, rates range from tens of K to tens of M and even hundreds of M. Broadband access technology has undergone tremendous changes in the decade. GPON has become the mainstream, EPON is catching up, and access technologies such as 10G PON that can bring higher bandwidth are gaining momentum.

With the booming development of broadband networks, the competition for technology selection has already relegated to second place. How to better apply xPON technology to the real network has become the direction for the development and exploration of fiber access technology.

A total platform to abandon the technological dispute

Whether it is GPON or EPON, this is the focus of the most debates in the industry. People have given different answers in terms of technology, business, and maturity. However, for operators, we can find a solution that is suitable for the existing network infrastructure, but also taking into account the future business development, while reducing OPEX - Huawei SingleFAN solution leads the direction of a common platform.

Wu Haijun, chief engineer of Huawei's product line access network product line, said, “The SingleFAN solution advocates the integration of multiple networks, high-capacity, low-cost office, and flat network architecture. It is highly recognized by major operators in Europe and reduces CO emissions. Points can greatly reduce the construction cost and network maintenance costs.” Wu Haijun said, “At the same time, SingleFAN solution advocates a multi-purpose network, full scene coverage, to achieve full-service PON network bearer, becoming the preferred solution for integrated operators.”

It is understood that the SingleFAN solution has sufficient future-oriented evolution capabilities, and sufficient capacity is reserved at all levels, including system capacity, software architecture, and service development. It can provide ATM to IP, and copper access to fiber access. From PSTN to IMS, from IPv4 to IPv6, from xPON to NG PON, and other comprehensive smooth evolution, to maximize investment protection.

The development direction of the EPON/GPON common platform led by SingleFAN has also been recognized by domestic operators and has become the basic requirement in the bidding.

Solve ODN management problems

In the development of FTTx, the access layer needs to build a huge fiber distribution network, namely ODN network. The cost of ODN network construction is high, and can account for 50%-70% of the total investment, which is the focus of FTTx investment. At the same time, ODN is also a difficulty in FTTx management. First of all, compared with the simple P2P structure of copper lines, ODN uses P2MP topology, and there are many nodes in the network, and the network management is complicated. Second, optical fibers are more sensitive than copper and are more likely to be damaged.

Therefore, it is very important for efficient construction, operation and maintenance of ODNs. It requires a set of intelligent and accurate management solutions to ensure that ODN networks are fully utilized and effectively protect long-term investment. At present, how to scientifically manage the ODN network has become the focus of attention of major operators and ITU-T standards organizations.

So, can we solve the two core issues of ODN management without changing the passive characteristics of ODN and realize the automatic management of ODN? Huawei proposed the iODN (Intelligent ODN) solution. In the iODN solution, ODN products have added the following intelligent features: fiber identification management, port status collection, port lookup indication, and visualization tools such as PDA.

The iODN solution enables the automatic entry and management of ODN fiber connection information, ensuring accurate and timely synchronization of inventory system information. At the same time, through PDA's visualization software and intelligent LED indications on the iODN device, it can realize optical fiber automation search and precise operation, greatly improve the operation and maintenance efficiency, and achieve efficient operation and maintenance of the ODN network. In addition, based on the iODN architecture, a variety of value-added applications can be developed on the basis of the inventory system to realize automation of the entire process of construction and operation and maintenance.

Introduce MPLS into the access layer

With the advancement of FTTx, on the one hand, the traditional dedicated line services have also experienced a dilemma with the withdrawal of ATM switches. A large number of dedicated line services need to be accessed with high quality guarantees. If the services of access bearers are built separately, it will impose a huge burden on operators. On the other hand, the traditional DSLAM mode service configuration mainly uses VLAN configurations and is subject to its VLANs. The limitation of the ID number (4K) imposes limitations on the development and planning of new services; and because the development of new services usually spans the entire network, cross-departmental operations are numerous and the efficiency of business development and distribution is low. To this end, the industry has proposed the introduction of MPLS technology into the access layer.

The value of MPLS in wide area networks has been confirmed. It simplifies the processing of data packets and improves the efficiency of data packet forwarding. MPLS-based traffic engineering and fast route protection technologies improve network QoS. As metropolitan area network architectures tend to flatten and OLT locations move up, MPLS is expanding from wide area networks to metropolitan areas and access networks. At present, the MAN is gradually evolving from the TDM/ATM network architecture to the Ethernet network architecture. The adoption of MPLS technology in MANs and access networks based on Ethernet will become a trend.

At present, operators such as Deutsche Telekom, France Telecom, etc. have already requested that future OLT devices can support this function. At the global MPLS Forum previously held by Huawei, Huawei demonstrated for the first time its solution for supporting MPLS on the OLT, and passed the interoperability test of the international authoritative testing organization EANTC. This has become the only OLT solution that passed the test in this field, and succeeded in Operators such as Accor in Germany have opened this function.

However, some experts also pointed out that the MPLS protocol is more complex than the traditional Layer 2 access. Therefore, equipment vendors are required to have a thorough understanding of routing protocols. For example, MPLS itself has a large number of protocols. Actually, these protocols do not all need to be implemented at the access layer, as long as they are selected. From the device perspective, MPLS greatly improves the performance requirements of access devices and improves the management capabilities of devices. From a cost perspective, MPLS at the access layer will increase the cost of equipment. Therefore, its current demand is mainly concentrated in developed countries that are more concerned with operational efficiency and help reduce OPEX. However, from the perspective of future long-term development, access-layer MPLS is a major direction for future product development.

Light Copper Advance

With the gradual advancement of copper into copper, DSL access nodes gradually move down, and market share will decrease year by year. However, Wei Leping, director of the Science and Technology Committee of China Telecom Corporation, believes that DSL will have at least 10 years of survival as a means of achieving the last hundred meters of access for users. "DSL, as the main method of user home access, will coexist with PON for 10 years."

This 10-year living space will also lead DSL technology to make breakthrough changes. At present, VDSL2 has been continuously optimized, using SuperMIMO technology and other multi-line bundled technology has made significant technological breakthroughs in ultra-high bandwidth DSL, can provide a higher bandwidth at a shorter distance, this technology is also developed for copper Line technology and fiber optic technology coexist better.

At the same time, in the field of mobile services, a cost-effective backhaul solution is provided for 3G/LTE deployment, and technologies such as time synchronization, bonding, and crosstalk processing are also introduced on copper lines. In January of this year, Huawei announced the launch of the world's first DSL prototype supporting 1588v2 time synchronization. This product can transmit 1588v2 high-precision time synchronization signals over a DSL line. The prototype test accuracy reaches the GPS level. This technical breakthrough means that operators have a more economical backhaul technology choice in the deployment process of 3G/4G, and can use widely deployed copper resources to quickly get rid of GPS deployment restrictions.

People's demand for higher bandwidth has never stopped, so technology innovation continues. A more compact, smart, flatter broadband access network has taken shape.