Cisco思科 网络 技术 培训 技术CHAP17

1、cisco 思科 网络 技术 培训 技术chap17 cisco 思科 网络 技术 培训 文档 objectives upon completion of this chapter, you will be able : to understand frame relay terminology describe the components and terminology used in frame relay networks compare different topology options available in frame relay designs, recognizing t

2、he costs and the benefits of each copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 chapter topics frame relay overview advantages access devices services switching operation/lmi router interaction rfc 1490 dlci mapping/inverse arp network types nbma subinterfaces topology

3、options copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 cost and latency of point-to-point wan los angeles chicago redundancy incurs both circuit and port costs multiple-hop latency occurs in partial-mesh topologies copyright 1997, cisco systems, inc. courseid_modtitle# c

4、isco 思科 网络 技术 培训 文档 frame relay: cost-effective connectivity(6*5)/2 = 15 circuits one access interface one logical hop to any point copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 frame relay access devicescarrier frad frad logical dte to logical dce virtual circuits are

5、end-to-end copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 frame relay service and circuitscir 56 kbpspvc dlci 99 dlci 86 64 kbps 1.5 mbps data-link connection identifier (dlci) committed information rate (cir) access rate is 56 kbps, 64 kbps, or 1.544 mbps copyright 1997

6、, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 frame relay operation switchingp0 frame relay packet header data . frame relay switch p1 p2 frame relay packet header data . p0 switching table dlci = 100 in_port in_dlci out_port out_dlci p0 p0 100 350 p1 p2 200 275 dlci = 200 copyright

7、1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 frame relay operationlmi link management interface ansi t1.617 annex d itu-t q.933 annex a frame relay forum lmi frame relay switch lmi- pvc status - keepalives copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训

8、文档 rfc 1490 specifications for frame relay token ring token ring both bridged and routed traffic can be carried over frame relay copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 frame relay mappingarriving packet forwarded packet 10.0.0.0 routing table network address of i

9、nterface next router 10.0.0.0 172.16.1.2 main memory s0 frame relay map address of dlci next router 172.16.1.2 100 physical interface copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 inverse arp eliminates manual configuration router learns dlci from switch sends inverse a

10、rp request to each dlciframe relay switch frame relay map address of next router 172.16.1.2 dlci p0 switching table in_port in_dlci out_port out_dlci p0 100 350 p1 p2 200 275 100 p0 copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 interaction with routing protoco lssplit h

11、orizon prevents advertising of 10.0.0.0 or 12.0.0.0 10.0.0.0 advertised no knowledge of 12.0.0.0 10.0.0.0 a c no knowledge of 10.0.0.0 routing table network interface 10.0.0.0 serial 0 12.0.0.0 serial 0 12.0.0.0 advertised b 12.0.0.0 copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络

12、 技术 培训 文档 nbma network type nonbroadcast multiaccess (nbma) frame relay network is one subnet full mesh required for full connectivityknowledge of 12.0.0.0 10.0.0.0 s0 knowledge of 10.0.0.0 12.0.0.0 one subnet copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 subinterfaces

13、single physical interface appears as multiple logical interfaces overcomes split horizon each subinterface is a separate subnetlogical subnet s0.1 physical interface s0 knowledge of 12.0.0.0 10.0.0.0 s0.2 logical subnet knowledge of 10.0.0.0 12.0.0.0 copyright 1997, cisco systems, inc. courseid_modt

14、itle# cisco 思科 网络 技术 培训 文档 topology options several topology options exist nbma subinterface with full mesh subinterface with hub and spoke considerations number of pvcs required number of subnets required number of hops required copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术

15、培训 文档 nbma using full mesh considerations number of pvc = 6 s number of subnets = 1 number of hops a - = 1 b a b copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 subinterfaces using full mesh considerations number of pvcs = 6 number of subnets = 6 number of hops a - b = 1

16、a b copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 subinterfaces using hub and spoke considerations number of pvcs = 3 number of subnets = 3 number of hops a - b = 2hub site a b copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 dial-on-demand as backup for frame relay use a floating static route interesting packets initiate ddr when routing topology changesigrps administrative distance is 100 hub static routes administrative distance is 200 hub copyright 1997, cisco systems, inc. courseid_modtitle# cisco 思科 网络 技术 培训 文档 summary fram