chapter 7 enhanced igrp (eigrp) and open shortest path first (ospf)
DESCRIPTION
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). - PowerPoint PPT PresentationTRANSCRIPT
Chapter 7Enhanced 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)
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
10.16.0.0/12
10.32.0.0/12
192.168.25.0/24
Router(config)#router ospf 10 (local significant)Router(config-router)#network 10.16.0.0 0.15.255.255 area 1Router(config-router)#network 10.32.0.0 0.15.255.255 area 1Router(config-router)#network 192.168.25.0 0.0.0.255 area 0
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
DR
BDR
R2
R3 R4
R1
Why will we use areas?
I. Fast building routing table II. Decreasing overload on router III. Simpler troubleshooting
Hierarchical Design (Areas)
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
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.
Electing DR and BDR
1- Priority (0~255); 1 by default2- Router ID:
Router(config)#int loopback 0Router(config-if)#ip add 10.0.0.1 255.0.0.0Router(config-if)#no shut
If there is only physical interface If there is loopback interface
OSPF Metric
Metric= cost= (10^8/B.W in bps) Fast Ethernet= 100MbpsCost= 10^8/(100x10^6) =1
Ethernet= 10MbpsCost= 10^8/(10x10^6) =10
Serial= 1.54MbpsCost= 10^8/(1.54410^6) =64
Router(config)#int s0Router(config-if)#ip ospf hello-interval 40 Router(config-if)#ip ospf dead-interval 160 Router(config-if)#ip ospf priority 25Router(config-if)#ip ospf cost 20
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 InformationFull/Full/DRFull/BDRFull/2 way DR other
Debugging OSPF
Router#debug ip ospf packetRouter#debug ip ospf helloRouter#debug ip ospf adj
Manual Summarization
172.
16.1
6.0/
20
172.
16.3
2.0/
20
10.6
4.0.
0/12
10.9
6.0.
.0/1
2
172.
16.4
8.0/
20
10.8
0.0.
0/12
10.1
12.0
.0/1
2
.3 .4
1700A 1700B 2600A 2500 2600B
.2 .2 .2
f0.2
f0.1
s0.1
s1.1
s0/0.2
s0/0.2
s0.2
s0/1.1f0/0
.1f0/0.1
e0.1
Area 1 Area 0
Manual Summarization
In Router 2600A2600A(config)#router ospf 102600A(config-router)#network 172.16.32.0 0.0.15.255 area 12600A(config-router)#network 172.16.48.0 0.0.15.255 area 12600A(config-router)#network 10.64.0.0 0.15.255.255 area 02600A(config-router)#area 1 range 172.16.0.0 255.255.192.0
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)
EIGRP Packets
1- Hello Packet2- Update Packet3- Query Packet4- Reply Packet5- Acknowledge Packet
1- Hello PacketMulticast 224.0.0.10 each (5 sec), holddown (15 sec)
2- Update Packet
Neighbors Table
Neg. IPMy Int.
Topology Table
Net1Path1 Succ
Net1Path2 F.Succ
Net1Path3 F.Succ
Net2Path1 Succ
Net2Path2 F.Succ
Net3Path1 Succ
Routing Table
Net1Path1 Succ
Net2Path1 Succ
Net3Path1 Succ
DU
AL
Alg
.D
UA
L A
lg.
DU
AL
Alg
.D
UA
L A
lg.
50 2030
40 40
Next Hop
R.D= Reported Distance
Next Hop
R.D= Reported Distance
F.D= Feasible Distance
F.D= Feasible Distance
F.D= Next Hop + R.D F.D of Succ. > R.D of F. Succ (New Succ)
3- Query PacketHolddown (180 sec), (16 x 5 sec)
4- Reply Packet
5- Acknowledge Packet
10.16.0.0/12
10.32.0.0/12
192.168.25.0/24
Router(config)#router eigrp 10 (AS)Router(config-router)#network 10.0.0.0Router(config-router)#network 192.168.25.0Router(config-router)#no auto-summery
Variance Vector
New Best Path ≤ Variance x Old Best Path
Topology Table
Net1Path1 Succ1000
Net1Path2 F.Succ1500
Net1Path3 F.Succ2000
Net1Path4 F.Succ3000
New Best Path ≤ 2 x 1000New Best Path ≤ 2000
Topology Table
Net1Path1 Succ1000
Net1Path2 F.Succ1500
Net1Path3 F.Succ2000
Net1Path4 F.Succ3000
Router(config)#eigrp 10Router(config-router)#variance 2Router(config-router)#maximum-paths 6
Manual Summarization
172.
16.1
6.0/
20
172.
16.3
2.0/
20
10.6
4.0.
0/12
10.9
6.0.
.0/1
2
172.
16.4
8.0/
20
10.8
0.0.
0/12
10.1
12.0
.0/1
2
.3 .4
1700A 1700B 2600A 2500 2600B
.2 .2 .2
f0.2
f0.1
s0.1
s1.1
s0/0.2
s0/0.2
s0.2
s0/1.1f0/0
.1f0/0.1
e0.1
IGRP EIGRP
Automatic Redistribution EIGRP with IGRP
172.
16.1
6.0/
20
172.
16.3
2.0/
20
200.
200.
200.
0/24
192.
168.
60.0
/24
172.
16.4
8.0/
20
192.
168.
50.0
/24
192.
168.
70.0
/24
.3 .4
1700A 1700B 2600A 2500 2600B
.2 .2 .2
f0.2
f0.1
s0.1
s1.1
s0/0.2
s0/0.2
s0.2
s0/1.1f0/0
.1f0/0.1
e0.1
Manual Summarization
Manual Summarization
2600A(config)#router eigrp 102600A(config-router)#network 172.16.0.02600A(config-router)#network 200.200.200.02600A(config-router)#no auto-summery2600A(config-router)#exit2600A(config)#int s0/12600A(config-if)#ip summary-address eigrp 10 172.16.0.0 255.255.192.0
Show and Debugging Commands
Router#sh ip eigrp neighborRouter#sh ip eigrp topologyRouter#sh ip routeRouter#sh ip route ripRouter#sh ip route igrpRouter#sh ip route ospfRouter#sh ip route eigrpRouter#debug eigrp packetRouter#debug ip eigrp notificationRouter#clear ip route *