The introduction of network technology into the electronic publishing system is a development trend at present and for a period of time in the future. However, how to follow the rapid development of network technology and establish a high-speed, high-speed, high-speed, high-performance, high-interoperability network hardware matching and low cost Local area network is the key to the introduction of network technology in electronic publishing systems.
Based on the current situation that Fast Ethernet is 100M in a local area network (LAN), it can be said that a transmission rate higher than 100M can be regarded as a high-speed local area network. Currently used technologies are mainly Gigabit Ethernet and ATM, and 10G Ethernet is being tested. Because Gigabit Ethernet has strong advantages and meets the networking requirements of fast operation, good interconnectivity, strong network hardware matching, and low cost of ownership, it can be identified as the preferred networking technology.
First, build several technologies applied in high-speed LAN
1. Wiring technology
Network cabling should use a combination of optical fiber and unshielded twisted pair wiring. Most of the current computer network cabling installed is unshielded twisted pair, and the standards followed are generally the "ultra-fifth" standards published by EIA/TIA and ISO. These performance standards meet the requirements of Gigabit Ethernet and asynchronous transfer modes at speeds higher than 1.2 Gbps. In LAN formation, the data transfer rate is not the deciding factor for using fiber. The cost comparison also shows that the unshielded twisted pair continues to be the primary reason for media selection in the horizontal channels that connect workstations. The cost of fiber is much higher than the cost of unshielded twisted pair, and the cost of passive components in fiber cabling is more than three times that of unshielded twisted pair. If you add the cost of active devices, such as hubs and network interface cards, the cost will increase further. However, distance restrictions are an inevitable choice for floor connections and intra-park interconnects using fiber. In addition, with the continuous popularization and popularization of network technology, the explosive growth of bandwidth requirements requires network cabling to consider the smooth upgrade in the future. Therefore, in structured cabling, network planners must consider the use of the highest-capacity cables because backbone installation conditions are generally very difficult. In the construction of the campus network, it is generally required that the fiber-to-the-cell and fiber-to-building systems be built. On the other hand, the cost of fiber optic cabling is significantly decreasing. This makes multi-mode optical fibers and single-mode optical fibers very cost-effective. Composite cables are now being installed in many buildings, ie, multi-mode fiber and single-mode fiber are used at the same time. This represents a new trend and it is worth noting. In a word, the network wiring in the electronic publishing system can use the optical fiber between the office building and the office building, and the unshielded twisted pair connection can be used between computers in a certain office building.
2. Link layer technology
Gigabit Ethernet can provide 1Gbps of communication bandwidth, and has the simplicity of Ethernet. It uses the same CSMA/CD protocol, the same frame format and the same frame length, also supports full-duplex and so on. The Gigabit Ethernet physical layer, like Ethernet and Fast Ethernet, only defines the physical layer and media access control layer. The physical layer is a key component of Gigabit Ethernet. Three transmission media are defined in IEEE 802.3z: multimode fiber, single-mode fiber, and coaxial cable. IEEE 802.3ab defines unshielded twisted pair media. In addition to the above several transmission media, there is a multi-vendor defined standard 1000base-LH, which is also an optical fiber standard, and the transmission distance can reach up to 100 kilometers. Another feature of the Gigabit Ethernet physical layer is the 8B/10B encoding, which is the same as the Fibre Channel technology. The same benefit is that network equipment vendors can use existing 8B/10B encoding/decoding chips, which will undoubtedly shorten the product development cycle and reduce costs.
3. Multi-layer switching technology
Switching technology can be divided into Layer 2 switching and multilayer switching from the current perspective. Multi-layer switching technologies include Layer 3 switching and Layer 4 switching.
The second layer of switching is called OSI Layer 2 or MAC layer switching. It is a switch in our usual sense. The technology is very mature. It works at the data link layer and the exchange is based on the MAC address.
Layer 3 switching, or network layer switching, is at Layer 3 of the OSI protocol. It provides higher-layer services such as routing functions. In the past, routers were commonly used to implement interconnection between networks. However, routers, which are expensive and have slow forwarding speeds, have increasingly become network bottlenecks. The wire-speed switching technology is now used to integrate routing functions into switches. Such switches are called routing switches or Layer 3 switches. They can realize wire-speed switching at various network levels, and their performance is greatly improved. The network topology and services on the third level are preserved. These structures and services have great advantages in terms of network segmentation, security, manageability, and suppression of broadcasts. The goal of the Layer 3 switch is to replace the existing routers, which provide information flow communication between subnets, increasing the communication speed from hundreds of packets per second to millions of packets per second. Layer 3 switching is designed to forward multiple protocols at high speed, or to provide firewalls to protect network resources, or to achieve bandwidth reservation, and LAN backbone switches will be Layer 3 switches.
Layer 4 switches can make intelligent decisions about where to forward session traffic. Due to this, the user's request can be forwarded to the "best" server according to different rules. Therefore, Layer 4 switching technology is an ideal mechanism for data transmission and load balancing among multiple servers.
The multi-layer switching technology has been described as an integrated, complete solution that can support various LAN architectures. It integrates switching technology and routing technology intelligently. Multi-layer switching technology combines the best features of LAN switching technology and routing technology. It has a higher performance-cost ratio and more flexibility than traditional router-based LAN backbones. It is the basis for high-speed LAN implementation.
Second, the need to consider the issue
The networking mode of high-speed LANs is now very simple, and there is no better choice: Basically, Gigabit Ethernet is the backbone, and high-performance Layer 2 and Layer 3 switches are used as the core; in terms of network cabling, between backbones and switches The connection is recommended to use multi-mode or single-mode fiber, horizontal wiring can use ultra-five unshielded twisted pair. According to the above, this kind of structure is easy to expand and upgrade. In addition, the switch products that support this networking mode are also rich. However, if a network is successfully established, it must also consider the following issues:
1. Business development. Whether the business can be carried out or whether the function is limited is the main criterion for various technical evaluations. Today's high-speed information networks are built to require integrated services including voice, video, and data. Therefore, whether to support various VLANs or support IP multicast is a problem that must be considered when selecting products. Even electronic publishing systems should be considered as they develop in the future.
2. Mature technology. Whether it is a computer network technology of a gigabit LAN or a high-speed router, there are actually problems with incomplete control domains. When conducting key data services or continuous media information communications, there will be many insurmountable obstacles. Immature network technologies should not be used lightly. This is the basic principle for setting up high-speed LANs for key services.
3. Network interoperability and network interoperability are the most important manifestations of network value. Network interoperability is not only reflected in the geographic coverage area, but also in the interconnection with other networks. The interoperability of high-speed LANs is mainly reflected in the interworking with existing networks and interworking with higher-level networks. This point is very important for the future development of the network, because in a random period of time, a variety of different nature and role of the network will gradually join the network to achieve information sharing between different areas and different industries.
4. Network reliability. Network reliability must be supported through network protocols, device backup, and route backup. In particular, whether the control and management system of the network protocol itself has high reliability is very important.
The establishment of high-speed local area networks provides a powerful guarantee for the publishing industry to achieve information sharing and improve work efficiency. More importantly, with the popularization and popularization of broadband network technology, it has also laid a solid foundation for the publishing industry to realize the integration of printing, the remote transmission of remote printing of printed pages, and the realization of online publishing.
Based on the current situation that Fast Ethernet is 100M in a local area network (LAN), it can be said that a transmission rate higher than 100M can be regarded as a high-speed local area network. Currently used technologies are mainly Gigabit Ethernet and ATM, and 10G Ethernet is being tested. Because Gigabit Ethernet has strong advantages and meets the networking requirements of fast operation, good interconnectivity, strong network hardware matching, and low cost of ownership, it can be identified as the preferred networking technology.
First, build several technologies applied in high-speed LAN
1. Wiring technology
Network cabling should use a combination of optical fiber and unshielded twisted pair wiring. Most of the current computer network cabling installed is unshielded twisted pair, and the standards followed are generally the "ultra-fifth" standards published by EIA/TIA and ISO. These performance standards meet the requirements of Gigabit Ethernet and asynchronous transfer modes at speeds higher than 1.2 Gbps. In LAN formation, the data transfer rate is not the deciding factor for using fiber. The cost comparison also shows that the unshielded twisted pair continues to be the primary reason for media selection in the horizontal channels that connect workstations. The cost of fiber is much higher than the cost of unshielded twisted pair, and the cost of passive components in fiber cabling is more than three times that of unshielded twisted pair. If you add the cost of active devices, such as hubs and network interface cards, the cost will increase further. However, distance restrictions are an inevitable choice for floor connections and intra-park interconnects using fiber. In addition, with the continuous popularization and popularization of network technology, the explosive growth of bandwidth requirements requires network cabling to consider the smooth upgrade in the future. Therefore, in structured cabling, network planners must consider the use of the highest-capacity cables because backbone installation conditions are generally very difficult. In the construction of the campus network, it is generally required that the fiber-to-the-cell and fiber-to-building systems be built. On the other hand, the cost of fiber optic cabling is significantly decreasing. This makes multi-mode optical fibers and single-mode optical fibers very cost-effective. Composite cables are now being installed in many buildings, ie, multi-mode fiber and single-mode fiber are used at the same time. This represents a new trend and it is worth noting. In a word, the network wiring in the electronic publishing system can use the optical fiber between the office building and the office building, and the unshielded twisted pair connection can be used between computers in a certain office building.
2. Link layer technology
Gigabit Ethernet can provide 1Gbps of communication bandwidth, and has the simplicity of Ethernet. It uses the same CSMA/CD protocol, the same frame format and the same frame length, also supports full-duplex and so on. The Gigabit Ethernet physical layer, like Ethernet and Fast Ethernet, only defines the physical layer and media access control layer. The physical layer is a key component of Gigabit Ethernet. Three transmission media are defined in IEEE 802.3z: multimode fiber, single-mode fiber, and coaxial cable. IEEE 802.3ab defines unshielded twisted pair media. In addition to the above several transmission media, there is a multi-vendor defined standard 1000base-LH, which is also an optical fiber standard, and the transmission distance can reach up to 100 kilometers. Another feature of the Gigabit Ethernet physical layer is the 8B/10B encoding, which is the same as the Fibre Channel technology. The same benefit is that network equipment vendors can use existing 8B/10B encoding/decoding chips, which will undoubtedly shorten the product development cycle and reduce costs.
3. Multi-layer switching technology
Switching technology can be divided into Layer 2 switching and multilayer switching from the current perspective. Multi-layer switching technologies include Layer 3 switching and Layer 4 switching.
The second layer of switching is called OSI Layer 2 or MAC layer switching. It is a switch in our usual sense. The technology is very mature. It works at the data link layer and the exchange is based on the MAC address.
Layer 3 switching, or network layer switching, is at Layer 3 of the OSI protocol. It provides higher-layer services such as routing functions. In the past, routers were commonly used to implement interconnection between networks. However, routers, which are expensive and have slow forwarding speeds, have increasingly become network bottlenecks. The wire-speed switching technology is now used to integrate routing functions into switches. Such switches are called routing switches or Layer 3 switches. They can realize wire-speed switching at various network levels, and their performance is greatly improved. The network topology and services on the third level are preserved. These structures and services have great advantages in terms of network segmentation, security, manageability, and suppression of broadcasts. The goal of the Layer 3 switch is to replace the existing routers, which provide information flow communication between subnets, increasing the communication speed from hundreds of packets per second to millions of packets per second. Layer 3 switching is designed to forward multiple protocols at high speed, or to provide firewalls to protect network resources, or to achieve bandwidth reservation, and LAN backbone switches will be Layer 3 switches.
Layer 4 switches can make intelligent decisions about where to forward session traffic. Due to this, the user's request can be forwarded to the "best" server according to different rules. Therefore, Layer 4 switching technology is an ideal mechanism for data transmission and load balancing among multiple servers.
The multi-layer switching technology has been described as an integrated, complete solution that can support various LAN architectures. It integrates switching technology and routing technology intelligently. Multi-layer switching technology combines the best features of LAN switching technology and routing technology. It has a higher performance-cost ratio and more flexibility than traditional router-based LAN backbones. It is the basis for high-speed LAN implementation.
Second, the need to consider the issue
The networking mode of high-speed LANs is now very simple, and there is no better choice: Basically, Gigabit Ethernet is the backbone, and high-performance Layer 2 and Layer 3 switches are used as the core; in terms of network cabling, between backbones and switches The connection is recommended to use multi-mode or single-mode fiber, horizontal wiring can use ultra-five unshielded twisted pair. According to the above, this kind of structure is easy to expand and upgrade. In addition, the switch products that support this networking mode are also rich. However, if a network is successfully established, it must also consider the following issues:
1. Business development. Whether the business can be carried out or whether the function is limited is the main criterion for various technical evaluations. Today's high-speed information networks are built to require integrated services including voice, video, and data. Therefore, whether to support various VLANs or support IP multicast is a problem that must be considered when selecting products. Even electronic publishing systems should be considered as they develop in the future.
2. Mature technology. Whether it is a computer network technology of a gigabit LAN or a high-speed router, there are actually problems with incomplete control domains. When conducting key data services or continuous media information communications, there will be many insurmountable obstacles. Immature network technologies should not be used lightly. This is the basic principle for setting up high-speed LANs for key services.
3. Network interoperability and network interoperability are the most important manifestations of network value. Network interoperability is not only reflected in the geographic coverage area, but also in the interconnection with other networks. The interoperability of high-speed LANs is mainly reflected in the interworking with existing networks and interworking with higher-level networks. This point is very important for the future development of the network, because in a random period of time, a variety of different nature and role of the network will gradually join the network to achieve information sharing between different areas and different industries.
4. Network reliability. Network reliability must be supported through network protocols, device backup, and route backup. In particular, whether the control and management system of the network protocol itself has high reliability is very important.
The establishment of high-speed local area networks provides a powerful guarantee for the publishing industry to achieve information sharing and improve work efficiency. More importantly, with the popularization and popularization of broadband network technology, it has also laid a solid foundation for the publishing industry to realize the integration of printing, the remote transmission of remote printing of printed pages, and the realization of online publishing.
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