On-line connection without marriage
The reliability of online services today is in demand not only in business, for the continuity of business processes, but also in everyday life. After all, the Internet has long been a part of everyday life, just as necessary as water, heat and electricity. In order to provide its subscribers with quality service, the provider needs a modern network infrastructure.
Access networks allow you to use telecommunications services to millions of families who want to connect high-speed home Internet or choose a package of services, including cable TV and the Internet. At the expense of what their reliability is provided, allowing us to use the Internet at any time, to communicate with friends, to watch TV? What is the basis of modern telecommunications services, through which subscribers get access to the Internet, television, telephone?
Currently, OnLime offers full-fledged Triple Play services - broadband Internet access, television (digital and interactive) and telephony. There are other services on the network, for example, video surveillance, taking readings from house meters of water and heat consumption (a separate VPN is allocated for transferring such data).
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Let's see how the network is organized by OnLime, a Rostelecom telecom provider in Moscow.
The backbone urban network is built using a ring architecture, which allows the use of DWDM (Dense Wavelength-Division Multiplexing) protection mechanisms with a dense recovery time of less than 50 ms. The ring redundancy of the DWDM network allows Onlayma to increase the reliability, throughput and efficiency of its use; moreover, it is a reserve for the future: - the basis of technical readiness to bypass growing volumes of traffic.
She repeats the administrative division of Moscow, covering all metropolitan districts.
Each trunk district node includes a television head station and an IP / MPLS router. All 10 district communications centers are combined into a physical ring using DWDM, and they logically form a double star, which is based on two powerful nodes of the IP / MPLS network core. From the district communications centers, within each district, district rings extend through all the districts, in turn, in each of which district communications centers are located. Each district ring rests on two different district trunk nodes. The structure of regional nodes includes the equipment of aggregation and the regional head television station. There are also several district rings in each district. They pass through the whole area. They rely on so-called clusters — small access rings covering groups of 10 houses. Thus, this entire network structure resembles a daisy with petals in the form of circumferential, district rings and access rings.
The ring architecture of the broadband network was not chosen randomly. In cable TV networks, fault tolerance is traditionally provided by means of ring topologies: the television signal in them is transmitted in two directions and controlled by optical switches. If the signal disappears in one direction, the backup is picked up.
In 2007, together with the Moscow government, it was decided to modernize television broadcasting - antennas disappeared from the roofs of houses, and all television broadcasting went into optical networks. Today, the same networks are used for data transmission - broadband Internet access. At the aggregation and core level of the network, the main protocols are IP / MPLS, and at the access network level, the Spanning Tree protocol.
At the core of the OnLime broadband network is the high-performance Alcatel-Lucent 7950 XRS-20 with high port density, the very two nodes that were discussed above. It is to these two points that all subscriber traffic flows. They are connected with the “outside world” through the backbone of Rostelecom and the main points of Internet traffic exchange: M9, M10, MSK-IX, SPB-IX, etc.
The Alcatel-Lucent XRS 7950 is a powerful backbone routing platform. It solves a wide range of tasks faced by operators. Supporting up to 160 100GE ports on a single chassis, the 7950 XRS provides a full range of capabilities for IP routing, MPLS switching and the creation of new services. The system includes 20 slots with an aggregate performance of each 400 Gbps and supports interfaces 10GE, 40GE, 100GE.
The OnLime network uses standard boundary access switches from well-established vendors - Edge-CorE, Qtech, and others. In the city it is 44 thousand switches. Subscribers are directly connected to them via a “twisted pair”.
Alternative geographically separated routes help to achieve high network resiliency. A single accident at the district or district level does not affect its performance. In the network of "Rostelecom" all lines are looped: break in one place - the signal will go through the ring on the other side. Only in case of a double accident in the ring, some of the subscribers can remain without communication for a while. As a rule, such accidents are unlikely.
The principle of redundancy laid the foundation of cable TV networks. Now there are 10 district and 110 regional stations in the On-Line cable TV networks. At the head stations, a terrestrial antenna is used to back up the television signal. The central head station forms the entire telepack - 50 channels of the “usual” cable and more than 200 channels of digital TV. They are transmitted via the IP / MPLS network to the district headquarters, which distributes them over the district via the optical network - in each district. When a circuit station fails, the television signal is automatically picked up by the neighboring head station and sent to the district.
Optical TV switches at each district television station choose the best signal from several sources and transmit it on. Thus, redundancy is carried out at each site of the cable TV network. A television signal comes to each house from two directions in optics, and a two-input optical receiver transmits a signal to a coaxial television network of a residential building. Learn more about how interactive and digital TV "OnLime" works here .
Alternative operators build their district-level access networks in the capital with the help of so-called air-cable crossings (VKP). These cables, stretched between buildings, are familiar to every inhabitant. The solution is not very aesthetic, but inexpensive - after all, access to the sewer is expensive. For this reason, sewage is used only to ensure connectivity at the city level. In the case of the OnLime network, it contains a double star DWDM (trunk level) and circumferential optical rings (aggregation level). A logical question arises, how reliable is all this web of optical cables? In fact, cliffs are quite rare.
Even during the freezing rain of 2010, ONLIM successfully passed the “tensile test”: only a few houses were left without communication for a while. This is one of the most reliable access networks in Moscow.
So, the entire OnLime fiber optic network, up to the house switch, is reserved. For any single accident in the ring, connectivity is not lost. However, the line from the house switch to the subscriber is not reserved. The fiber goes only to the equipment of the company installed in the house. Inside the house, from the switch, a “twisted pair” Category 5e is laid along the low-current riser to the subscriber's premises. Theoretically, this is a weak link. Possible damage to the cable, breaks.
More often a different situation arises. Often, users complain about the inconsistency of the actual data transfer rate declared by the provider speed. Meanwhile, the tariff plan indicates only the speed response of the selected channel. Not everyone understands that the claimed speed is the speed at which the user is “allowed into the network”. That is, the speed within the network provider. Minor errors in speed measurement are also possible. In addition, a variety of factors affect the download speed, for example, loading the channel to the server, loading the server itself, and computer hardware and software. And not the fact that the user's computer equipment or his home network Wi-Fi provide such speed. And not all sites on the Internet are sufficiently “smart” for this. By the way, after 30 Mbit / s, the increase in speed will not make networking more comfortable - the difference will be noticeable only in the download time of large files.
In order to conduct explanatory work among users, OnLime launched a special project - “Speed ​​Laboratory”. As part of the project, a team of On-Line professionals comes to the subscribers' home and measures the speed of the Internet. The goal is to make sure that the speed corresponds to that stated in the tariff.
Currently deployed fiber optic access networks are based on various architectures and technologies. The carefully thought-out standards for these technologies and the availability of the necessary equipment determine the dynamic development of this industry, encouraging large telecom operators to invest in fiber-optic access networks.
The Onlaym network is growing and developing all the time, the network equipment is updated with products from new lines. Specialists are constantly monitoring network load - the number of connected subscribers in different homes can vary significantly. Growth of subscriber base (increases the load on the access network. When the capacity of its individual segments is used by more than 80%, it’s time to think about upgrading - switching to faster 10 / 100GbE interfaces or organizing new data channels. However, the broadband access network architecture and basic principles redundancy, ensuring the reliability of network services, remain unchanged.
Access networks allow you to use telecommunications services to millions of families who want to connect high-speed home Internet or choose a package of services, including cable TV and the Internet. At the expense of what their reliability is provided, allowing us to use the Internet at any time, to communicate with friends, to watch TV? What is the basis of modern telecommunications services, through which subscribers get access to the Internet, television, telephone?
Currently, OnLime offers full-fledged Triple Play services - broadband Internet access, television (digital and interactive) and telephony. There are other services on the network, for example, video surveillance, taking readings from house meters of water and heat consumption (a separate VPN is allocated for transferring such data).
')
Let's see how the network is organized by OnLime, a Rostelecom telecom provider in Moscow.
Ring to ring
The backbone urban network is built using a ring architecture, which allows the use of DWDM (Dense Wavelength-Division Multiplexing) protection mechanisms with a dense recovery time of less than 50 ms. The ring redundancy of the DWDM network allows Onlayma to increase the reliability, throughput and efficiency of its use; moreover, it is a reserve for the future: - the basis of technical readiness to bypass growing volumes of traffic.
She repeats the administrative division of Moscow, covering all metropolitan districts.
Each trunk district node includes a television head station and an IP / MPLS router. All 10 district communications centers are combined into a physical ring using DWDM, and they logically form a double star, which is based on two powerful nodes of the IP / MPLS network core. From the district communications centers, within each district, district rings extend through all the districts, in turn, in each of which district communications centers are located. Each district ring rests on two different district trunk nodes. The structure of regional nodes includes the equipment of aggregation and the regional head television station. There are also several district rings in each district. They pass through the whole area. They rely on so-called clusters — small access rings covering groups of 10 houses. Thus, this entire network structure resembles a daisy with petals in the form of circumferential, district rings and access rings.The ring architecture of the broadband network was not chosen randomly. In cable TV networks, fault tolerance is traditionally provided by means of ring topologies: the television signal in them is transmitted in two directions and controlled by optical switches. If the signal disappears in one direction, the backup is picked up.
In 2007, together with the Moscow government, it was decided to modernize television broadcasting - antennas disappeared from the roofs of houses, and all television broadcasting went into optical networks. Today, the same networks are used for data transmission - broadband Internet access. At the aggregation and core level of the network, the main protocols are IP / MPLS, and at the access network level, the Spanning Tree protocol.
At the core of the OnLime broadband network is the high-performance Alcatel-Lucent 7950 XRS-20 with high port density, the very two nodes that were discussed above. It is to these two points that all subscriber traffic flows. They are connected with the “outside world” through the backbone of Rostelecom and the main points of Internet traffic exchange: M9, M10, MSK-IX, SPB-IX, etc.
The Alcatel-Lucent XRS 7950 is a powerful backbone routing platform. It solves a wide range of tasks faced by operators. Supporting up to 160 100GE ports on a single chassis, the 7950 XRS provides a full range of capabilities for IP routing, MPLS switching and the creation of new services. The system includes 20 slots with an aggregate performance of each 400 Gbps and supports interfaces 10GE, 40GE, 100GE.
The OnLime network uses standard boundary access switches from well-established vendors - Edge-CorE, Qtech, and others. In the city it is 44 thousand switches. Subscribers are directly connected to them via a “twisted pair”.
Alternative geographically separated routes help to achieve high network resiliency. A single accident at the district or district level does not affect its performance. In the network of "Rostelecom" all lines are looped: break in one place - the signal will go through the ring on the other side. Only in case of a double accident in the ring, some of the subscribers can remain without communication for a while. As a rule, such accidents are unlikely.
The principle of redundancy laid the foundation of cable TV networks. Now there are 10 district and 110 regional stations in the On-Line cable TV networks. At the head stations, a terrestrial antenna is used to back up the television signal. The central head station forms the entire telepack - 50 channels of the “usual” cable and more than 200 channels of digital TV. They are transmitted via the IP / MPLS network to the district headquarters, which distributes them over the district via the optical network - in each district. When a circuit station fails, the television signal is automatically picked up by the neighboring head station and sent to the district.
Optical TV switches at each district television station choose the best signal from several sources and transmit it on. Thus, redundancy is carried out at each site of the cable TV network. A television signal comes to each house from two directions in optics, and a two-input optical receiver transmits a signal to a coaxial television network of a residential building. Learn more about how interactive and digital TV "OnLime" works here .
Under the earth and in the sky
Alternative operators build their district-level access networks in the capital with the help of so-called air-cable crossings (VKP). These cables, stretched between buildings, are familiar to every inhabitant. The solution is not very aesthetic, but inexpensive - after all, access to the sewer is expensive. For this reason, sewage is used only to ensure connectivity at the city level. In the case of the OnLime network, it contains a double star DWDM (trunk level) and circumferential optical rings (aggregation level). A logical question arises, how reliable is all this web of optical cables? In fact, cliffs are quite rare.
Even during the freezing rain of 2010, ONLIM successfully passed the “tensile test”: only a few houses were left without communication for a while. This is one of the most reliable access networks in Moscow.
"Brakes" and malfunctions
So, the entire OnLime fiber optic network, up to the house switch, is reserved. For any single accident in the ring, connectivity is not lost. However, the line from the house switch to the subscriber is not reserved. The fiber goes only to the equipment of the company installed in the house. Inside the house, from the switch, a “twisted pair” Category 5e is laid along the low-current riser to the subscriber's premises. Theoretically, this is a weak link. Possible damage to the cable, breaks.
More often a different situation arises. Often, users complain about the inconsistency of the actual data transfer rate declared by the provider speed. Meanwhile, the tariff plan indicates only the speed response of the selected channel. Not everyone understands that the claimed speed is the speed at which the user is “allowed into the network”. That is, the speed within the network provider. Minor errors in speed measurement are also possible. In addition, a variety of factors affect the download speed, for example, loading the channel to the server, loading the server itself, and computer hardware and software. And not the fact that the user's computer equipment or his home network Wi-Fi provide such speed. And not all sites on the Internet are sufficiently “smart” for this. By the way, after 30 Mbit / s, the increase in speed will not make networking more comfortable - the difference will be noticeable only in the download time of large files.
In order to conduct explanatory work among users, OnLime launched a special project - “Speed ​​Laboratory”. As part of the project, a team of On-Line professionals comes to the subscribers' home and measures the speed of the Internet. The goal is to make sure that the speed corresponds to that stated in the tariff.
Perspectives
Currently deployed fiber optic access networks are based on various architectures and technologies. The carefully thought-out standards for these technologies and the availability of the necessary equipment determine the dynamic development of this industry, encouraging large telecom operators to invest in fiber-optic access networks.
The Onlaym network is growing and developing all the time, the network equipment is updated with products from new lines. Specialists are constantly monitoring network load - the number of connected subscribers in different homes can vary significantly. Growth of subscriber base (increases the load on the access network. When the capacity of its individual segments is used by more than 80%, it’s time to think about upgrading - switching to faster 10 / 100GbE interfaces or organizing new data channels. However, the broadband access network architecture and basic principles redundancy, ensuring the reliability of network services, remain unchanged.
Source: https://habr.com/ru/post/268541/
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