精品推荐
阅读排行
· 工程竣工验收报告· 大学生毕业自我鉴定
· 大学生自我鉴定7
· 大学毕业生自我鉴定
· 大学生学年自我鉴定
· 大学毕业生自我鉴定
· 师范生实习鉴定评语
· 给老师的一封感谢信
· 心理健康教育论文
· 黑板报设计图欣赏
| 作者：不明 来源：www.pccode.net 整理 发布时间：2007-1-24 15:24:00 发布人：wongrs | |
|
nection-oriented and connectionless service from higher-layer protocols. protocols are typically routing protocols. BGP, OSPF, DLC, DecNet, ICMP, RIP, NLSP, IGRP, EIGRP, Packets and datagrams are sent across this layer. Data Link-Framing-putting 1’s & 0’s in to a logical group, provides reliable transmission of data across a physical medium. specifies different network and protocol characteristics, including physical addressing, network topology, error notification, sequencing of frames, and flow control. two sublayers known as the Media Access Control (MAC) and the Logical Link Control (LLC) layer. LLC- Provides flexibility to upper & lower protos. Respon timing, flow control, supports both conn less & conn oriented svcs used by upper protocols. MAC-respon for framing, access to physical net media.Eg. ARP. DLL implementations are LAN or WAN specs. LAN imples- Ethernet/IEEE 802.3, Fast Ethernet, FDDI, and Token Ring/IEEE 802.5,WAN imples.-Frame Relay, LAPB, SDLC, HDLC, X.25, SLIP, PPP. MAC Add. : 6 bytes ( 3 bytes- vendor code, 3 bytes- Serial No.) Ethernet_II -PreAmb8-DA6-SA6-Type2(upper layer proto ID)-Data-FCS 4 (Cyclic Redundancy Checksum). 802.2_Ethernet-PreAmb8-DA6-SA6-Length-DSAP-SSAP(802.2 LLC header)-Data-FCS.(MAC & LLC) 802.3_Ethernet-PreAmb8-DA6-SA6-Length-Data-FCS (MAC) (CSMA/CD-IEEE-802.3) can’t identify up layer protos. Physical-defines Bit synch & Physical topology, Specs define such as voltage levels, timing of voltage changes, physical data rates, max trans distances, and the physical conntrs be used. Eg. FDDI, SONET, ISDN. (Stds: v.24, v.35, x..21, G.703 ), LAN-imples-Ethernet/IEEE 802.3, Fast Ethernet, FDDI, and Token Ring/IEEE 802.5. WAN-imples- High-Speed Serial Interface (HSSI), SMDS Interface Protocol (SIP), and X.21bis. 10Base2-ThinNet-RG58-BNC-185 Mtrs, 100BaseT4-100MB,Cat 3/4/5, 802.3 10Base5-ThickNet-RG8-DIX/AUI-500Mts, 100 BaseTx-Cat5-STP-100 Mtrs.(Fast Enet over STP/802.3), 10BaseT-Cat3/4/5-100Mts. 100Base Fx-100MB,2 pr OFC 802.3 10/100Base FL-OFC-2 Km, 100Base VG Any LAN-OFC, 802.3 (Cisco does not support it) 100BaseT- CSMA/CD, 802.3u, Fast Enet, DOD Model : Proc / Appl : Telnet, FTP, LPD SNMP/ FTP, SMTP, NFS, X window, Host-
|
|
| [ ] [返回上一页] [打 印] [收 藏] | |
上一篇文章：CCNA Test prep ver1.0
下一篇文章：CISCO试题(1) |