Network Interface glossary collection

I. Differences between POS interface and GE Interface

POs (SDH-based data packet) interface and Ge (Gigabit Ethernet) interface are deeply analyzed, this article makes a full comparison between the two technologies to achieve wide-area data stream transmission efficiency, fault detection capabilities, and economics. It is proposed that both POS interface and GE interface can be used for wide-area transmission, flexible options.
Key words: GE, POs, transmission efficiency, fault detection capability, and economics
1,
Overview
As the number of Internet users rapidly increases, the demand for long-distance transmission network bandwidth is raised. The Internet bandwidth occupied by long-distance transmission is mainly used to achieve interconnection between core/aggregation routers, and a small number of major customers use Ethernet leased lines. All interfaces used by the core/Aggregation Router for wide-area interconnection are pos (Packet over SONET/SDH) interfaces, the speed is divided into 10 gpos, 2.5g POs, 622 m pos, and 155 m pos. Using POS interfaces to achieve vro wide-area interconnection is a popular practice. It has been proved by experiments that it is also a very effective and reliable method. The main disadvantage of this method is the high cost. If you can find a new networking method, such as a low-cost Ethernet networking method widely used in man, it will greatly reduce the network construction cost. Based on the analysis of Ethernet and Pos technologies, this paper makes a full comparison between the two technologies to achieve wide-area data stream transmission efficiency, fault detection capability, and economics, provides a reference for the networking of Internet Data devices.
2,
Ethernet and POS technology introduction
2.1 Ethernet Technology
The Ethernet interface is the most common interface for computer network interconnection. The Ethernet interface shows great vitality with its advantages of low cost and good compatibility. Ethernet includes the 802.3 standard and Dix Ethernet V2 standard. Two standard MAC frame formats: 1. The two standard Mac frames have 6-byte destination addresses and source addresses, 4-byte-long FCS, 2-byte-long type (or length), and Mac customer data is 4-bytes, the difference is that 802.3 frames have an LLC (Logical Link Control) Sub-layer.
In order to achieve bit synchronization, 8 bytes must be inserted before the frame when downloading from the MAC Sub-layer to the physical layer. The first 7 bytes are called the pre-synchronization code, and the first 8th bytes are the frame start delimiters, indicates that the message after the frame is a MAC frame. The MAC Sub-layer also specifies that the minimum interval between frames is 12 bytes.
Ethernet interfaces include 10base-t, 10base-f, 100base-t, 10base-fx, 1000base-x, and 1000base-t. Interfaces of GE and above are used in cross-city interconnection. GE physical interfaces include 1000base-x (802.3z standard) and 1000base-t (802.3ab standard.
2. POS technology
In fact, POS technology uses SONET/SDH devices/frame structures to transmit IP services. It uses the SDH standard frame structure, and uses the point-to-point transmission encapsulation technology to encapsulate the IP service and then transmit it on the optical fiber or transmission system. The POS standard encapsulation protocols mainly include PPP/HDLC, laps, and green code encapsulation protocols.
2.1. PPP/HDLC Protocol
The PPP/HDLC protocol is the most common IP over SDH link layer protocol. It groups IP data packets through PPP (Point-to-Point Protocol), and uses HDLC (Advanced Link Control) Protocol to define and hold frames for PPP groups according to rfc1662 specifications,
Finally, map it to the byte-based SDH virtual container, coupled with the corresponding overhead placed in the STM-N frame. The format of the PPP/HDLC frame is 2.
2.2 laps Protocol
Laps protocol is a type of HDLC protocol family. It has a lot of familiarity with the PPP/HDLC protocol. For example, it uses the mark byte 0x7e to define frames, and the control domain is still 0x03, however, the laps Information Section has removed the Protocol bytes and the padding bytes. The Protocol byte function has been moved to the address byte. Therefore, the laps protocol is simpler and more convenient than the PPP/HDLC protocol, and the encapsulation efficiency is higher.
2.3. Green Protocol
The green protocol is a new connectionless data link layer Encapsulation Protocol standardized by ITU-T g.7041, which can flexibly support the transfer of various data protocols today and in the future. The basic idea of the Green Data Protocol comes from a simple data link. It improves a general mechanism for physical transmission channels that adapt high-level customer signals to byte synchronization. The high-level customer signal encapsulated by the green code can be a data stream oriented to the Protocol Data Unit (PDU), or a fixed bit rate data stream oriented to block encoding.
The frame structure of the green code 3. The green frame is divided into the core header and the Net Load area. The core message header of the green code completes the data link management function of the green code, and implements the function of dividing the green code frames irrelevant to the high-level PDU. The green core header consists of four bytes, including the net charge length indication domain and the core header verification (CHEC) domain. The length of the Net Load area can be changed between 0 and, which generally refers to the business aspect of the green line, such as the business PDU, link layer code word, or the business management information of the Green Line. The net load is divided into three parts: the net load header (4-64 bytes), the net load information domain, and the Net Load FCS domain (4 bytes ). The first two parts are indispensable, and the third part is optional.
This section describes three common and standard encapsulation protocols for data services, pos interfaces include 155 Mbit/s, 622 Mbit/s, 2.5 Gbit/s, and 10 Gbit/s POS.

Ii. Passive Optic Network)

Pon is an overview of passive optical network access technology. Currently, GPON (ITU Protocol) and EPON (IEEE Protocol) are two different protocols. Pon devices include the local OLT, The ONU of the client, and the ODN of the Passive Optical splitting device connecting the OLT and ONU. Access Network Technology. Currently, XDSL is commonly used to connect electrical signals with network cables. Now, the optical access technology of PON will gradually replace the traditional electrical access technology.

 

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Network Interface glossary collection