hdlc

decimal: 202.112.14.159Exercise several times more and remember the conversion rules of decimal and binary.In 1.172.16.10.33/27,/27 indicates that the subnet mask is too large, that is, 27 All 12. according to the subnet mask 255.255.255.252, the network bit is 30 bits. Therefore, only the remaining two bits are used as the master bits, the network address is used for all the host bits, and the broadcast address is used for all the host bits, the remaining host numbers are in the host address r

The following describes the default *. pcap file storage format of ethereal. Description of each field in the pcap File Header 24B:Magic: 4b: 0x1a 2B 3C 4d: used to mark the start of the file Major: 2b, 0x02 00: The main version number of the current file minor: 2b, 0x04 00 current file minor version number thiszone: 4B local standard time; all zero sigfigs: 4B timestamp precision; all zero snaplen: 4B maximum storage length linktype: 4B common link types: 0 BSD loopback devices, ipvt for late

, the frame has a frame header and a frame tail, and the source object L2 address in the header, while the frame tail usually contains verification information, the content between the beginning and end is the user data. The data link layer provides many functions, so it is divided into two sub-layers: the MAC (Media Access Control) layer and the LLC (Logical Link Control) layer. The common L2 standard for LAN and man is IEEE 802 protocol. In the wide area network,

in advance that both the sending end and the receiving end are used as the divisor binary bits (or polynomials ); the second is to divide the original frame with the binary division operation selected above and calculate the FC. The former can be selected randomly or internationally,The maximum and maximum bits must be "1", For example, the CRC-16 used in IBM's SDLC (synchronous Data Link Control) procedure (that is, this divisor is a total of 17 bits) to generate polynomial g (x) =X16 +X15 +X2

(synchronous Data Link Control) HDLc (High-Level Data Link Control) PPP protocol is the most common protocol for independent link devices, Nic, and bridge is also a link product. Some of the features of the hub modem are considered to belong to the link layer. In addition, all switches must work on the data link layer, but only on the data link layer. Although other layer-3 switches, layer-4 switches, and layer-7 switches can work on the OSI Layer-3,

description (en): 12/7 /2003Http://www.joyfire.net/compress/cml2.pdf3. z8530 Programming Guide (en) Upload: 11/7 /2003Http://www.joyfire.net/compress/z8530book.pdf4. synchronous PPP and Cisco HDLC Programming Guide (en) Upload: 11/7 /2003Http://www.joyfire.net/compress/wanbook.pdf5. video4linux programming (en) Upload: 11/7 /2003Http://www.joyfire.net/compress/videobook.pdf6. the Linux 2.4 parallel port subsystem (en) Upload: 11/7 /2003Http://www.joy

Window and selection retransmission protocol (SR) (5) Media Access Control 1. Channel division Media Access Control Concepts and basic principles of multiplexing, multiplexing, division multiplexing, and code multiplexing. 2. Access Media Access Control immediately Aloha protocol; CSMA/CD Protocol; CSMA/CA protocol. 3. Round-Robin Access Media Access Control: token Transfer Protocol (6) LAN 1. Basic Concepts and architecture of LAN 2. Ethernet and IEEE 802.3 3. IEEE 802.11 4. Basic principles o

according to the source IP address. It is determined to be SSDP Based on the remote port 1900. Uplink and downlink interfaces of the network: the uplink interface accepts data and the downlink interface sends data. The uplink port of a router is generally an interface connecting to the optical fiber transceiver of a communications company. The downlink interface is connected to a vswitch or terminal at the user end. The uplink port of a vswitch refers to an interface connected to a vro or opti

videos.Session Layer:The establishment and completion of the session;Typical equipment: gateway;Typical protocols, standards, and Applications: RPC, SQL, NFS, X WINDOWS, ASPTransport Layer:Main function: End-to-end control transport;Typical equipment: gateway;Typical protocols, standards, and Applications: TCP, UDP, SPXNetwork layer:Main functions: routing, addressing network;Typical equipment: routers;Typical protocols, standards, and Applications: IP, IPX, APPLETALK, ICMP;Data Link Layer:Main

(MGC)-Media Gateway (MGW) interface Stage 3 H.248.1 Gateway Control Protocol: Version 3 3GPP tr23.930 IU principles 3GPP ts 25.410 UTRAN Iu interface general aspects and principles 3GPP ts 32.401 telecommunication management; performance management (PM); concept and requirements IMS 3GPP ts 22.228-a00 service requirements for the Internet Protocol (IP) multimedia core network subsystem (IMS); Stage 1.doc Rfc3261 sip-Session Initiation Protocol LTE (4G) (Simplified LTE network architect

one bit of data transmitted. Asynchronous transmission requires at least 20% overhead because "Start bit", "parity bit", and "Stop bit" must be added before and after each character data bit. ,Synchronous transmission requires only one frame with a few frame headers and frame tail fields, so the overhead and efficiency are much higher than that of asynchronous transmission. The HDLC overhead of common synchronization transmission link control protoco

port is forwarded to all ports. Link Layer Protocol: SDLC (synchronous Data Link Control) HDLc (High-Level Data Link Control) PPP protocol is the most common protocol for independent link devices, Nic, and bridge is also a link product. Some of the features of the hub modem are considered to belong to the link layer. In addition, all switches must work on the data link layer, but only on the data link layer. Although other layer-3 switches, layer-4 s

transfer, part of the exchange between users and remote computers is visible. Common application layer protocols include HTTP, FTP, telnet, SMTP, And gopher. The application layer is the most critical layer for Linux network settings. The configuration document of the Linux Server mainly targets the protocols in the application layer. The functions and protocols of the TCP/IP model are shown in Table 1-2. Table 1-2 Functions and protocols of the TCP/IP Model Level name Merit Ag

the data link layer into a data packet. The packet contains a network packet header, which contains the logical address information-the network address of the source site and the destination site. Routers work on this layer, and the network becomes interconnected by constantly receiving and transmitting data.Data Link Layer) The role of this layer includes physical address addressing, data frame formation, traffic control, data error detection, and re-transmission. At this layer, the unit of da

, IPX, and appletalk) and is designed to replace the non-standard protocol slip of the data link layer. The PPP protocol was designed after the original HDLC specification. Therefore, the designers of the PPP protocol include many additional features that were not considered in the WAN data link layer protocol until then. Both PPTP and L2TP use the PPP protocol to encapsulate data, and then add additional headers for data transmission over the Interne

check the CRC of the header and only control errors.18. Windows NT4.0 adopts the A, dll B, NLM C, Hal D, NDIS19. Among the three types of network services, X.25 is A, type a B, type B C, type C D, uncertain20. In the TCP/IP application, A, ftp B, TFTP C, Ping D, rexec Iii. Calculation questions (10 points for each question, a total of 20 points)1. What is the maximum data rate for a channel with a bandwidth of 64 KB, which of the following four levels can be obtained for a digital signal at any

) (also called Internet layer) Network Layer Network Interface Layer (also called Link Layer) Data Link Layer Physical Layer 1. Mechanical properties; 2. Electronic properties; 3. functional features; 4. procedure features. The data link layer is responsible for receiving IP data packets and sending them over the network, or receiving physical frames from the network, extracting IP data packets, and handing them over to the IP layer. Common interface layer protocols

the data terminal device (DTE) and the data circuit terminal device (DCE. DTE is located on the user's network interface client device; DCE provides physical connection interfaces to the network, providing Clock signal for data transmission between step DTE and DCE devices. in short, the DTE device is close to the user side, and the DCE device is close to the network. commonly Used for DTE devices: terminal hosts and routers; commonly used for DCE devices: Wan Switching Machine, moderm, CSU/DSU

Presentation Layer such as XDR, ASN.1, SMB, AFP, NCP 5 Session Layer For example ASAP, TLS, SSH, ISO 8327/ccitt x.225, RPC, NetBIOS, ASP, Winsock, BSD sockets 4 Transport Layer such as TCP, UDP, RTP, SCTP, SPX, ATP, IL 3 Network layer such as IP, ICMP, IGMP, IPX, BGP, OSPF, RIP, IGRP, EIGRP, ARP, RARP, x. 2 Data Link Layer such as Ethernet, Token Ring,

using a Web browser, and the Web server sends the requested information to the client.The following diagram attempts to show the location of the different TCP/IP and other protocols in the original OSI model: 7 Application Layer such as HTTP, SMTP, SNMP, FTP, Telnet, SIP, SSH, NFS, RTSP, XMPP, Whois, ENRP 6 Presentation Layer such as XDR, ASN.1, SMB, AFP, NCP 5 Session Layer For example ASAP, TLS, SSH, ISO 8327/ccitt x.