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Chapter 7 Enhanced IGRP (EIGRP) and Open Shortest Path First (OSPF)

Chapter 7 Enhanced IGRP (EIGRP) and Open Shortest Path First (OSPF). Link State Algorithm. Sends Update when it occurs only, link state protocols deal with three types of tables, they are: Neighbors table Topology table Route table. Open Shortest Path First (OSPF).

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Chapter 7 Enhanced IGRP (EIGRP) and Open Shortest Path First (OSPF)

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  1. Chapter 7Enhanced IGRP (EIGRP) and Open Shortest PathFirst (OSPF)

  2. Link State Algorithm • Sends Update when it occurs only, link state protocols deal with three types of tables, they are: • Neighbors table • Topology table • Route table

  3. Open Shortest Path First (OSPF) • Allows multi-vendor deployment (Open standard) R.P • Link state R.P • Classless R.P • Supports VLSM and discontiguous networks • Has unlimited hop count • Does not make auto-summery (because of using wildcard) • AD = 110 • “O” in Route Table • Used within one autonomous system (AS 1~65535) • Used with areas (2^32) • Supports authentication • Fast convergence

  4. 10.16.0.0/12 192.168.25.0/24 10.32.0.0/12 Router(config)#router ospf 10 (local significant) Router(config-router)#network 10.16.0.0 0.15.255.255 area 1 Router(config-router)#network 10.32.0.0 0.15.255.255 area 1 Router(config-router)#network 192.168.25.0 0.0.0.255 area 0

  5. OSPF Terminology • Link • Router ID RID • Neighbor Router • Adjacent Router • Designated Router DR • Backup Designated Router BDR • Hello protocol • Link State Advertisement LSA • Neighborship database • Topological database • OSPF areas R1 R2 DR BDR R3 R4

  6. Hierarchical Design (Areas) • Why will we use areas? • Fast building routing table • Decreasing overload on router • Simpler troubleshooting

  7. Neighbors table is constructed using Hello packets • LSA Packets are transmitted between routers to construct Topological database • Shortest path tree is constructed • Dijkstra or SPF algorithm to find best for destinations with multiple paths • Results go to the route table

  8. Network Types with OSPF 1- Point to Point Hello interval= 10 sec. Dead interval= 40 sec. 2- Point-to-multipoint Hello interval= 10 sec. Dead interval= 40 sec. 3- Broadcast (multi-access) Hello interval= 10 sec. Dead interval= 40 sec. 4- Non-broadcast multi-access NBMA (Frame-Relay or X.25) Hello interval= 30 sec. Dead interval= 120 sec.

  9. Electing DR and BDR 1- Priority (0~255); 1 by default 2- Router ID: If there is only physical interface If there is loopback interface Router(config)#int loopback 0 Router(config-if)#ip add 10.0.0.1 255.0.0.0 Router(config-if)#no shut

  10. OSPF Metric Metric= cost= (10^8/B.W in bps) Fast Ethernet= 100Mbps Cost= 10^8/(100x10^6) =1 Ethernet= 10Mbps Cost= 10^8/(10x10^6) =10 Serial= 1.54Mbps Cost= 10^8/(1.54410^6) =64 Router(config)#int s0 Router(config-if)#ip ospf hello-interval 40 Router(config-if)#ip ospf dead-interval 160 Router(config-if)#ip ospf priority 25 Router(config-if)#ip ospf cost 20

  11. Show Commands Router#sh ip ospf (Process ID, Area ID, RID, SPF statistics, and LSA timer information) Router#sh ip ospf database (Process ID, Area ID, RID, Topology Table) Router#sh ip ospf interface (Process ID, Area ID, RID, Interface IP address, Network type, Cost, Priority, DR/BDR election information (if applicable), Hello and Dead timer intervals, Adjacent neighbor information) Router#sh ip ospf neighbor (Process ID, Area ID, RID, Neighbors table, DR/BDR information) DR/BDR Information Full/ Full/DR Full/BDR Full/2 way DR other

  12. Debugging OSPF Router#debug ip ospf packet Router#debug ip ospf hello Router#debug ip ospf adj

  13. Manual Summarization Area 1 Area 0 172.16.32.0/20 10.96.0..0/12 10.64.0.0/12 1700A 1700B 2600A 2500 2600B s0 .1 s0/0 .2 s0/1 .1 s0 .2 s1 .1 s0/0 .2 f0 .1 f0 .2 f0/0 .1 e0 .1 f0/0 .1 172.16.48.0/20 172.16.16.0/20 10.112.0.0/12 10.80.0.0/12 .3 .2 .2 .2 .4

  14. Manual Summarization In Router 2600A 2600A(config)#router ospf 10 2600A(config-router)#network 172.16.32.00.0.15.255 area 1 2600A(config-router)#network 172.16.48.00.0.15.255 area 1 2600A(config-router)#network 10.64.0.00.15.255.255 area 0 2600A(config-router)#area 1 range 172.16.0.0 255.255.192.0

  15. Enhanced Interior Gateway Routing Protocol (EIGRP) • Cisco Proprietary R.P • Hybrid (advanced distance-vector) R.P • Classless R.P • Supports VLSM and discontiguous networks • Max. hops 255 (100 by default) • Makes auto-summery by default, auto-summery can be disabled • Use composite metric (B.W, Reliability, Delay, Load, MTU) • AD = 90 (for internal EIGRP route), AD = 170 (for external EIGRP route) • “D” in Route Table • Used within one autonomous system (AS 1~65535) • Best path selection via Diffusing Update Algorithm (DUAL) • The only R.P that supports for IP, IPv6, IPX, and Apple Talk via protocol dependent modules (PDM) • Communication via Reliable Transport Protocol (RTP)

  16. EIGRP Packets 1- Hello Packet 2- Update Packet 3- Query Packet 4- Reply Packet 5- Acknowledge Packet 1- Hello Packet Multicast 224.0.0.10 each (5 sec), holddown (15 sec) 2- Update Packet DUAL Alg.

  17. F.D= Feasible Distance R.D= Reported Distance Next Hop 30 50 20 40 40 Next Hop R.D= Reported Distance F.D= Feasible Distance F.D of Succ. >R.D of F. Succ (New Succ) F.D= Next Hop + R.D

  18. 3- Query Packet Holddown (180 sec), (16 x 5 sec) 4- Reply Packet 5- Acknowledge Packet 10.16.0.0/12 192.168.25.0/24 10.32.0.0/12 Router(config)#router eigrp 10 (AS) Router(config-router)#network 10.0.0.0 Router(config-router)#network 192.168.25.0 Router(config-router)#no auto-summery

  19. Variance Vector New Best Path ≤ Variance x Old Best Path New Best Path≤ 2 x 1000 New Best Path≤ 2000 Router(config)#eigrp 10 Router(config-router)#variance 2 Router(config-router)#maximum-paths 6

  20. Manual Summarization Automatic Redistribution EIGRP with IGRP IGRP EIGRP 172.16.32.0/20 10.96.0..0/12 10.64.0.0/12 1700A 1700B 2600A 2500 2600B s0 .1 s0/0 .2 s0/1 .1 s0 .2 s1 .1 s0/0 .2 f0 .1 f0 .2 f0/0 .1 e0 .1 f0/0 .1 172.16.48.0/20 172.16.16.0/20 10.112.0.0/12 10.80.0.0/12 .3 .2 .2 .2 .4

  21. Manual Summarization 200.200.200.0/24 192.168.60.0/24 172.16.32.0/20 1700A 1700B 2600A 2500 2600B s0 .1 s0/0 .2 s0/1 .1 s0 .2 s1 .1 s0/0 .2 f0 .1 f0 .2 f0/0 .1 e0 .1 f0/0 .1 192.168.50.0/24 192.168.70.0/24 172.16.48.0/20 172.16.16.0/20 .3 .2 .2 .2 .4

  22. Manual Summarization 2600A(config)#router eigrp 10 2600A(config-router)#network 172.16.0.0 2600A(config-router)#network 200.200.200.0 2600A(config-router)#no auto-summery 2600A(config-router)#exit 2600A(config)#int s0/1 2600A(config-if)#ip summary-address eigrp 10 172.16.0.0 255.255.192.0

  23. Show and Debugging Commands Router#sh ip eigrp neighbor Router#sh ip eigrp topology Router#sh ip route Router#sh ip route rip Router#sh ip route igrp Router#sh ip route ospf Router#sh ip route eigrp Router#debug eigrp packet Router#debug ip eigrp notification Router#clear ip route *

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