二零二三年 优质公开课SegmentingtheIPNetwork.pptx

《HCNA-HNTD Fast Training》Segmenting the IP Network课程团队：叶礼兵 王苏南 张悦 吴伟强 Foreword The forwarding of frames and switching has introduced the data link layer operations, and in particular the role of IEEE 802 based standards as the supporting underlying communication mechanism, over which upper layer protocol suites generally operate. With the introduction of routing, the physics that define upper layer protocols and internetwork communication are established. An enterprise network domain generally consists of multiple networks for which routing decisions are needed to ensure optimal routes are used, in order to forward IP packets (or datagrams) to intended network destinations. This section introduces the foundations on which such IP routing is based.Page 2 Objectives Upon completion of this section, trainees will be able to:Explain the principles that govern IP routing decisions.Explain the basic requirements for packet forwarding.Page 3 Autonomous SystemsPage 4An IP network, or networks, controlled by one or more operators with a clear policy that governs how routing decisions are made. Local Area Network and Broadcast DomainsPage 5Broadcast DomainBroadcast DomainLAN 3LAN 2LAN 1 Routing DecisionsPage 6?DestinationRouters are responsible for the decision making process that determines the path via which packets are forwarded. IP Routing TablePage 7[Huawei]display ip routing-table Route Flags: R - relay, D - download to fibRouting Tables: Public Destinations : 2 Routes : 2 Destination/Mask Proto Pre Cost Flags NextHop Interface 127.0.0.0/8 Direct 0 0 D 127.0.0.1 InLoopBack0 127.0.0.1/32 Direct 0 0 D 127.0.0.1 InLoopBack0 The IP routing table lists the networks that are reachable via the router. Packets that have no route are subsequently discarded. Routing Decisions – Longest MatchPage 820.1.1.0/3010.1.1.0/30RTARTBRTC.1.1.2.2Ethernet0/0/0[RTA]display ip routing-table Destination/Mask Proto Pre Cost Flags