OSPFv3 Is A Link-State Routing Protocol Developed From OSPFv2 And Used For IPv6 Networks.OSPFV3 Is To IPv6 What OSPFV2 Is To IPv4. OSPF Is Defined As OSPF Version 2 In RFC 2328 (1998) For IPv4. The Updates For IPv6 Are Specified As OSPF Version 3 In RFC 5340 (2008).
FOR MORE OSPF REFERENCES:
1. ◙ - ➤ Protocol Comparison OSPF, EIGRP, BGP And RIP:
2. ◙ - ➤ OSPFv2 (IPv4) Vs OSPFv3 (IPv6)
3. ◙ - ➤ OSPF Quick Reference:
4. ◙ - ➤ OSPF Quick IOS Commands Reference Table:
5. ◙ - ➤ Short Notes Of OSPF:
6. ◙ - ➤ OSPF LSA Operation And It’s Types:
7. ◙ - ➤ OSPF Configuration Examples:
8. ◙ - ➤ OSPF MD5:
9. ◙ - ➤ Redistribution OSPF Vs EIGRP:
10. ◙ - ➤ OSPF Review Questions And Answers:
11. ◙ - ➤ Just Recap About OSPF With Quest:
12. ◙ - ➤ IPv6 OSPF VIRTUAL-LINK:
SHORT RECAP ABOUT OSPF
◙ - ➤ “Open” = Open Standard.
◙ - ➤ Development Began In 1987 by IETF
◙ - ➤ OSPFv2 - RFC 2328 (1998), Latest Revision Is 3.
◙ - ➤ Full Support for VLSM And Route Summarization.
◙ - ➤ Metric: Administratively Defined Cost.
◙ - ➤ (Default 100 Mbps/ Bandwidth)
◙ - ➤ Uses IP For Transport, IP Protocol 89
◙ - ➤ Uses Multicast Addresses For Neighbor Maintenance And Flooding Of LSAs.
• 224.0.0.5 – All OSPF Routers
• 224.0.0.6 – All DRouters
OPEN SHORTEST PATH FIRST (OSPF)Is A Link-State Routing Protocol Based On Open Standards (The Open In OSPF Means That It Is Open To The Public And Is Non-Proprietary). Runs The Dijkstra Algorithm To Find The Best Path.
OSPF Is A Routing Protocol That Calls For The Sending Of Link-State Advertisements (LSAs) To All Other Routers Within The Same Hierarchical Area. An Area Is A Group Of Contiguous Networks And Attached Hosts. OSPF LSAs Include Information On Attached Interfaces, Metrics Used, And Other Variables. As OSPF Routers Accumulate Information, The Routers Use The SPF Algorithm To Calculate The Shortest Path To Each Node. This Is Different From The Way Distance-Vector Protocols Work. Distance-Vector Protocols Send All Or A Portion Of Their Routing Tables In Routing-Update Messages To Their Neighbors.
THE FOLLOWING TABLE DESCRIBES THE DETAILED COMMAND OUTPUT FIELDS FOR AN OSPF INTERFACE OSPF TERMS:
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X.25, Frame Relay And Similar Technologies.
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OSPF CONFIGURATION AND TROUBLESHOOTING OSPF COMMANDS REFERENCES:
◙ - ➤ Router(Config-Router)#Network 172.16.0.0 0.0.255.255 Area 0 - > OSPF Advertises Interfaces, Not Networks. Uses The Wildcard Mask To Determine Which Interfaces To Advertise.
◙ - ➤ Router(Config-If)#IP OSPF Hellointerval Timer 20 - > Changes The Hello Interval Timer To 20 Seconds.
◙ - ➤ Router(Config-If)#IP OSPF Deadinterval 80 - > Changes The Dead Interval Timer To 80 Seconds.
Note: Hello And Dead Interval Timers Must Match For Routers To Become Neighbors.
◙ - ➤ Router#Clear IP Route * - > Clears Entire Routing Table, Forcing It To Rebuild.
◙ - ➤ Router#Clear IP Route A.B.C.D - > Clears Specific Route To Network A.B.C.D
◙ - ➤ Router#Clear IP OPSF Counters - > Resets OSPF Counters.
◙ - ➤ Router#Clear IP OSPF Process - > Resets Entire OSPF Process, Forcing OSPF To Re-Create Neighbors, Database, And Routing Table.
◙ - ➤ Router#Show IP Protocol - > Displays Parameters For All Protocols Running On The Router.
◙ - ➤ Router#Show IP Route - > Displays A Complete IP Routing Table.
◙ - ➤ Router#Show IP OSPF - > Displays Basic Information About OSPF Routing Processes.
◙ - ➤ Router#Show IP OSPF Interface - > Displays OSPF Info As It Relates To All Interfaces.
◙ - ➤ Router#Show IP OSPF Interface Fastethernet 0/0 - > Displays OSPF Information For Interface Fastethernet 0/0.
◙ - ➤ Router#Show IP OSPF Border-Routers - > Displays Border And Boundary Router Information.
◙ - ➤ Router#Show IP OSPF Neighbor - > Lists All OSPF Neighbors And Their States.
◙ - ➤ Router#Show IP OSPF Neighbor Detail - > Displays A Detailed List Of Neighbors.
◙ - ➤ Router#Debug IP OSPF Events - > Displays All OSPF Events.
◙ - ➤ Router#Debug IP OSPF Adjacency - > Displays Various OSPF States And DR/ BDR Election Between Adjacent Routers.
◙ - ➤ Router#Debug IP OSPF Packets - > Displays OPSF Packets.
REQUIRED OSPF CONFIGURATION COMMANDS – REVIEW: Router(Config)# Router OSPF Process-ID
Router(Config-Router)#Network Address Wildcard-Mask Area Area-ID
OPTIONAL OSPF CONFIGURATION COMMANDS – REVIEW: Router(Config-Router)# Default-Information Originate - > (Send Default).
Router(Config-Router)# Area Area Authentication - > (Plain Authentication).
Router(Config-Router)# Area Area Authentication Message-Digest - > (MD5 Authentication).
Router(Config)# Interface Loopback Number - > (Configure Loopback As Router ID).
Router(Config)# Interface Type Slot/Port
Router(Config-If)# IP OSPF Priority <0-255> - > (DR/BDR Election).
Router(Config-If)# Bandwidth Kbps - > (Modify Default Bandwdth).
Router(Config-If)# IP OSPF Cost Cost - > (Modify Inter. Cost).
Router(Config-If)# IP OSPF Hello-Interval Seconds - > (Modify Hello).
Router(Config-If)# IP OSPF Dead-Interval Seconds - > (Modify Dead).
Router(Config-If)# IP OSPF Authentication-Key Passwd - > (Plain/MD5 Authentication).
RouterConfig-If)# IP OSPF Message-Digest-Key Key-ID MD5 Password
ENABLING OSPF: Process ID: The Process ID Is The ID Of The OSPF Process To Which The Interface Belongs. The Process ID Is Local To The Router, And Two OSPF Neighboring Routers Can Have Different OSPF Process IDs.
Router(config)# Router OSPF Process-ID
◙ Process-ID: 1 - 65,535
◙ Cisco Feature, Which Allows You To Run Multiple, Different Ospf Routing Processes On The Same Router. (But Don’t!)
◙ Process-ID Is Locally Significant, And Does Not Have To Be The Same Number On Other Routers (They Don’t Care).
◙ This Is Different Than The Process-ID Used For IGRP And EIGRP Which Must Be The Same On All Routers Sharing Routing Information.
FYI - Cisco IOS Limits The Number Of Dynamic Routing Processes To 30. This Is Because It Limits The Number Of Protocol Descriptors To 32, Using One For Connected Route Sources, One For Static Route Sources, And 30 For Dynamic Route Sources.
CONFIGURING NETWORK COMMAND AND THE WILDCARD MASK: Router(Config)# Router OSPF Process-ID
Router(Config-Router)#Network Address Wildcard-Mask Area Area-ID
◙ Tells OSPF Which Interfaces To Enable OSPF On (Send And Receive Updates), Matching The Address And Wildcard Mask.
◙ Also, Tells OSPF To Include This Network In Its Routing Updates
◙ Wildcard Is Necessary Because OSPF Supports CIDR And VLSM
◙ Most Of The Time You Can Just Use An Inverse-Mask (Like Access-Lists) As The Network Wildcard Mask.
Router(Config-If)#IP Add 20.10.5.1 255.255.255.0
Router(Config)# Router OSPF 10
Router(Config-Router)#Network 20.10.5.0 0.0.0.255 Area 0
EXAMPLE FOR THE NETWORK WILDCARD MASK ON ROUTER R1: Router R1(Config)#Router OSPF 1
Router R1(Config-Router)#Network 192.168.1.0 0.0.0.255 Area 0
Router R1(Config-Router)#Network 192.168.2.0 0.0.0.255 Area 0
Router R1(Config-Router)#Network 192.168.20.0 0.0.0.3 Area 0
EXAMPLE FOR THE NETWORK WILDCARD MASK ON ROUTER R2: Router R2(Config)#Router OSPF 10
Router R2(Config-Router)#Network 192.168.20.0 0.0.0.3 Area 0
Router R2(Config-Router)#Network 192.168.30.0 0.0.0.255 Area 0
OSPF DR/BDR: On OSPF Multiaccess Segment, We Wanted R1 To Become The DR And R2 To Become The BDR.
R1(config)# Interface f0/0
R1(config-if)# IPv6 OSPF Priority 100
R2(config)# Interface f0/0
R2(config-if)# IPv6 OSPF Priority 90
DRs Cannot Be Preempted By Routers With A Higher Priority Once They Have Been Elected, So We'll Need To Disconnect All Routers From The Network In Order To Force A New Election. When The Interfaces Come Back Online, We See That R1 And R2 Have Been Elected As The DR And BDR, Respectively.
YOU WANT TO CHANG DR OR BDR AFTER YOU CHANGE THE PRIORITY, YOU CAN DO LIKE THIS: Router1#Clear IP OSPF Process
Reset ALL OSPF Processes? [No]: Yes
Router2#Clear IP OSPF Process
Reset ALL OSPF Processes? [No]: Yes
TO VERIFY: Which Neighbors Are The OSPD DR/BDR/DROTHER By Using The “Show IP OSPF Neighbor” Command In Privileged Mode.
Router#Show IP OSPF Neighbor
The “Show IP OSPF Interface” Command.
This Command Shows Important Information Such As The DR, The BDR, A List Of Neighbors, And The Network Type.
OSPF COMMANDS:
OSPF AREA DEFAULT-COST
OSPF AREA RANGE
CLEAR IP OSPF
DEFAULT-INFORMATION ORIGINATE
DISCARD-ROUTE
IP OSPF AUTHENTICATION
IP OSPF AUTHENTICATION-KEY
IP OSPF COST
IP OSPF DEAD-INTERVAL
IP OSPF HELLO-INTERVAL
IP OSPF MESSAGE-DIGEST-KEY
IP OSPF MTU-IGNORE
IP OSPF PRIORITY
IP OSPF RETRANSMIT-INTERVAL
NETWORK AREA
ROUTER OSPF
LOG-ADJACENCY-CHANGES
REDISTRIBUTE CONNECTED
REDISTRIBUTE RIP
REDISTRIBUTE STATIC
ROUTER-ID
SHOW IP OSPF
SHOW IP OSPF BORDER-ROUTERS
SHOW IP OSPF DATABASE
SHOW IP OSPF INTERFACE
SHOW IP OSPF NEIGHBOR
SHOW IP OSPF ROUTE
TIMERS SPF
SUMMARY-ADDRESS
AREA STUB:
Define An Area As A Stub.
area <area ID> stub [no-summary]
no area <area ID> stub
Where:
No-Summary - Summary Link Advertisements Are Not Sent Into The Area.
The No Form Of The Command Disables This Function.
Example:
Router(config)#Router OSPF Router (OSPF)#Area 1 Stub No-Summary Router (OSPF)#
AREA DEFAULT-COST:
Specify The Cost For The Default Route Injected Into The Stub Area.
area <area ID> default-cost <cost>
no area <area ID> default-cost
The no Form Of The Command Resets The Cost To The Default Value Of 1.
Example:
Router(config)#Router OSPF Router(OSPF)#Area 1 Default-Cost 20 Router(ospf)#
AREA RANGE:
Summarize Routes At An Area Boundary.
area <area ID>range <CIDR range> [not-advertise]
no area <area ID> range <CIDR range>
where:
<CIDR range> - range of addresses to be summarized.
not-advertise - suppress type 3 summary LSA generation.
The No Form Of The Command Will Remove The Summarization.
Example:
Router(Config)#Router OSPF Router(OSPF)#Area 1 Range 1.2.3.0/24 Not-Advertise Router(OSPF)#
CLEAR IP OSPF:
Reset OSPF Protocol.
Clear IP OSPF
Reset OSPF statistics.
Clear IP OSPF Statistics
Start A Short Path First (SPF) Calculation.
Clear IP OSPF Force-SPF
DEFAULT-INFORMATION ORIGINATE:
Insert The Default Route Into OSPF Database. The Route Will Be Exchanged With The Other Routers.
[no] default-information originate
The No Form Of The Command Removes The Default Route From OSPF Database.
Example:
Router(Config)#Router OSPF Router(OSPF)#Default-Information Originate Router(OSPF)#
DISCARD-ROUTE:
Install Or Do Not Install Blackhole Routes Introduced By Summarization.
[no] discard-route [internal | external]
By Default, Blackhole Routes Introduced By Summarization Are Installed.
Example:
Router(OSPF)#Show IP Route OSPF Codes: C - connected, S - static, R - RIP, B - blackhole, O - OSPF IA - OSPF inter area, E1 - OSPF external type 1, E2 - OSPF external type 2 O E1 1.2.1.0/24[110/23] via 10.1.0.66, br0 O E2 1.3.1.0/24[110/50] via 10.1.0.3, br0 O B 10.0.0.0/23 <<< Summarization Blackhole Route Installed By Default O IA 10.0.2.0/23[110/9] via 10.1.0.3, br0 O E1 10.0.4.0/24[110/29] via 10.1.0.3, br0 rcp(ospf)#no discard-route rcp(ospf)#show ip route ospf Codes: C - connected, S - static, R - RIP, B - blackhole, O - OSPF IA - OSPF inter area, E1 - OSPF external type 1, E2 - OSPF external type 2 O E1 1.2.1.0/24[110/23] via 10.1.0.66, br0 O E2 1.3.1.0/24[110/50] via 10.1.0.3, br0 O IA 10.0.2.0/23[110/9] via 10.1.0.3, br0 O E1 10.0.4.0/24[110/29] via 10.1.0.3, br0 Router(OSPF)#
IP OSPF AUTHENTICATION:
IP OSPF Authentication
Enable Simple Password Authentication
IP OSPF Authentication Message-Digest
Enable MD5 Authentication
No IP OSPF Authentication
The no Form Of The Command Disables Authentication.
Example:
Router(Config)#Interface Ethernet eth0 Router(Config-if eth0)#IP OSPF Authentication Message-Digest Router(config-if eth0)#
IP OSPF AUTHENTICATION-KEY:
Set Password For OSPF Simple Password Authentication.
IP OSPF Authentication-key <password>
No IP OSPF Authentication-Key
The no Form Of The Command Removes The Password.
Example:
Router(Config)#Interface Ethernet eth0 Router(config-if eth0)#IP OSPF Authentication-key Mysecret Router(Config-if eth0)#
IP OSPF COST:
Specify The Cost Of Sending A Packet On An Interface.
ip ospf cost <cost>
no ip ospf cost
The no Form Of The Command Sets The Cost To The Default Value Of 1.
Example:
Router(Config)#Interface Ethernet eth0 Router(config-if eth0)#IP OSPF cost 10 Router(config-if eth0)#
IP OSPF DEAD-INTERVAL:
Set OSPF Dead Interval For The Interface.
ip ospf dead-interval <seconds>
no ip ospf dead-interval
The no Form Of The Command Sets The Dead Interval To The Default Value Of 40.
Example:
Router(Config)#Interface Ethernet eth0 Router(config-if eth0)#IP OSPF Dead-Interval 4 Router(config-if eth0)#
IP OSPF HELLO-INTERVAL:
Set OSPF Hello Interval For The Interface.
ip ospf hello-interval <seconds>
no ip ospf hello-interval
The No Form Of The Command Sets The Hello Interval To The Default Value Of 10.
Example:
Router(Config)#Interface Ethernet eth0 Router(Config-if eth0)#IP OSPF Hello-Interval 1 Router(Config-if eth0)#
IP OSPF MESSAGE-DIGEST-KEY:
Set password for OSPF MD5 authentication.
IP OSPF Message-digest-key <key ID> md5 <password>
No IP OSPF Message-Digest-Key
The No Form Of The Command Removes The Password.
Example:
Router(Config)#Interface Ethernet eth0 Router(Config-if eth0)#IP OSPF Message-digest-key 22 md5 Mysecret Router(config-if eth0)#
IP OSPF MTU-IGNORE:
Disabled MTU Mismatch Detection.
[no] ip ospf mtu-ignore
The No Form Of The Command Enables The Detection.
Example:
Router(Config)#Interface Ethernet eth0 Router(Config-if eth0)#IP OSPF Mtu-ignore Router(Config-if eth0)#
IP OSPF PRIORITY:
Set OSPF Priority For The Interface.
IP OSPF Priority <priority>
NO IP OSPF Priority
The No Form Of The Command Sets The Priority To The Default Value Of 1.
Example:
Router(Config)#Interface Ethernet eth0 Router(config-if eth0)#IP OSPF Priority 5 Router(config-if eth0)#
IP OSPF RETRANSMIT-INTERVAL:
Set OSPF Retransmit Interval For The Interface.
IP OSPF Retransmit-interval <seconds>
No IP OSPF Retransmit-Interval
The no Form Of The Command Sets The Retransmit Interval To The Default Value Of 5.
Example:
Router(Config)#Interface Ethernet eth0 Router(config-if eth0)#IP OSPF Retransmit-interval 10 Router(config-if eth0)#
NETWORK AREA:
Define An Area ID And Enable OSPF On A Network.
[no] network <CIDR address> area <area ID>
The no Form Of The Command Removes The Network.
Example:
Router(Config)#Router OSPF Router(OSPF)#Network 10.1.0.0/16 Area 0 Router(OSPF)#
ROUTER RIP:
Enter OSPF Configuration Mode.
router ospf
Use Exit Command To Return To Configuration Mode.
Example:
Router(Config)#Router OSPF Router(OSPF)#Exit Router(config)#
LOG-ADJACENCY-CHANGES:
Send Syslog Messages When An OSPF Neighbor Goes Up Or Down.
[no] ospf log-adjacency-changes [detail]
where:
Detail - Log Any Neighbor State Changes.
The no Form Of The Command Disables Logging.
Example:
Router(Config)#Router ospf Router(OSPF)#OSPF Log-Adjacency-Changes Detail Router(OSPF)#
REDISTRIBUTE CONNECTED:
Distribute Connected Routes Using OSPF.
[No] Redistribute Connected [metric <metric>] \
[metric-type <type>] [tag <tag>]
[No] Redistribute Connected Loopback
where:
Metric - Metric Used For Generating The Route, Default Value 10.
Type - OSPF External Type 1 Or Type 2 Routes, Default Type 2.
Tag - 32-Bit Tag Value, Default Value 0.
Loopback - Redistribute Loopback Interface Addresses
The No Form Of The Command Removes The Connected Routes From OSPF Database.
Example:
Router(Config)#Router OSPF Router(OSPF)#Redistribute Connected Metric 50 Metric-Type 1 Router(OSPF)#
REDISTRIBUTE RIP:
Distribute RIP routes using OSPF.
[no] redistribute rip [metric <metric>] [metric-type <type>] [tag <tag>]
where:
Metric - Metric Used For Generating The Route, Default Value 10.
Type - OSPF External Type 1 Or Type 2 Routes, Default Type 2.
Tag - 32-Bit Tag Value, Default Value 0.
The No Form Of The Command Removes The RIP Routes From OSPF Database.
Example:
Router(Config)#Router OSPF Router(OSPF)#Redistribute Rip Metric 50 Metric-Type 1 Router(OSPF)#
REDISTRIBUTE STATIC:
Distribute Static Routes Using OSPF.
[No] Redistribute Static [metric <metric>] [metric-type <type>] [tag <tag>]
where:
Metric - Metric Used For Generating The Route, Default Value 10.
type - OSPF External Type 1 Or Type 2 Routes, Default Type 2.
Tag - 32-Bit Tag Value, Default Value 0.
The No Form Of The Command Removes The Static Routes From OSPF Database.
Example:
Router(Config)#Router OSPF Router(OSPF)#Redistribute Static Metric 50 Metric-type 1 rcp(ospf)#
ROUTER-ID:
Set OSPF Router ID. If The Router Already Has OSPF Neighbors Active, It Is Necessary To Restart OSPF Protocol Using clear ip ospf Command.
router-id <IP address>
If Router ID Is Not Specified, OSPF Will Use The Highest IP Address Configured On Any Interface.
Example:
Router(Config)#Router OSPF Router(OSPF)#Router-ID 10.1.1.1 Router(OSPF)#
SHOW IP OSPF:
Display General OSPF Information.
Show IP OSPF
Example:
Router#Show IP OSPF Ospf Router Id 192.168.1.22 Conforms To Rfc2328, Rfc1583 Compatibility Flag Is Disabled Supports Only Single Tos(Tos0) Routes This Is An Area Border Router This Is An As Border Router SPF Schedule Delay 2 Seconds, Number Of Spf Calculations 2 Last Spf Calculation Fri Jun 29 09:30:08 2012 Number Of External Lsa 2 Number Of Lsa Originated 23 Area 2: Number Of Lsa 12 Network 10.2.0.0/24, 1 Neighbors (0 Down, 0 2way, 1 Full) Area 1: Number Of Lsa 12 Network 10.1.0.0/24, 1 Neighbors (0 Down, 0 2way, 1 Full) Area 0: Number Of Lsa 15 Network 10.0.0.0/24, 2 Neighbors (0 down, 0 2way, 2 full) Router#
SHOW IP OSPF BORDER-ROUTERS:
Display Network Border Routers.
Show IP OSPF Border-Routers
Example:
rcp#Show IP OSPF Border-Routers i 192.168.10.2 [1], ABR, ASBR, area 0 i 192.168.10.1 [1], ASBR, area 0 rcp#
SHOW IP OSPF DATABASE:
Display OSPF Database.
show ip ospf [<area ID>] database \
router | network | summary | asbr-summary | external | self-originate \
[detail]
Example:
rcp#Show IP OSPF Database Router Link States (Area 0) Link ID ADV Router Age Seq# Checksum Link count 192.168.1.22 192.168.1.22 564 0x80000028 0xd240 1 10.0.21.10 10.0.21.10 583 0x8000000d 0xceae 2 10.0.22.11 10.0.22.11 583 0x80000007 0x8de4 2 10.0.22.1 10.0.22.1 584 0x80000009 0x7309 2 10.0.21.1 10.0.21.1 590 0x80000009 0x275c 2 10.0.11.1 10.0.11.1 566 0x80000016 0xaffb 2 10.0.12.1 10.0.12.1 565 0x8000000b 0xe3cd 2 Network Link States (Area 0) Link ID ADV Router Age Seq# Checksum 10.0.3.1 10.0.21.10 583 0x8000000e 0x18a9 10.0.22.1 10.0.22.1 584 0x8000000a 0x0cb6 10.0.21.1 10.0.21.1 590 0x8000000a 0xfdc9 10.0.12.1 10.0.12.1 598 0x8000000a 0xd911 10.0.0.10 10.0.11.1 566 0x80000017 0x86e6 10.0.11.1 10.0.11.1 566 0x80000018 0xb927 Summary Link States (Area 0) Link ID ADV Router Age Seq# Checksum 10.1.0.0 192.168.1.22 561 0x8000002e 0x6f30 10.2.0.0 192.168.1.22 561 0x8000002d 0x653a AS External Link States Link ID ADV Router Age Seq# Checksum Type Tag 10.0.41.0 10.0.22.11 584 0x80000006 0x1399 E1 0 10.0.40.0 10.0.21.10 591 0x8000000c 0x9495 E2 0 rcp#
SHOW IP OSPF INTERFACE:
Display OSPF Interface Information.
show IP OSPF Interface
Example:
Router#Show IP OSPF Interface Interface br2, admin state UP, link state UP IP address 10.2.0.1/24, MTU 1500 Router ID 192.168.1.22, network type BROADCAST, cost 1 Transmit delay is 0, network state Backup, priority 1 Hello interval 1, dead interval 4, wait time 4, retransmit interval 5 Designated router 10.2.0.10, backup designated router 10.2.0.1 Hello packets received 1830, sent 1830, errors 0 Database Description packets received 4, sent 3, rxmt 0, errors 0 LS Request packets received 1, sent 1, rxmt 0, errors 0 LS Update packets received 29, sent 19, rxmt 0, errors 0 LS Acknowledgment packets received 19, sent 29, errors 0 Neighbor count is 1, adjacent neighbor count is 1 Interface br1, admin state UP, link state UP IP address 10.1.0.1/24, MTU 1500 Router ID 192.168.1.22, network type BROADCAST, cost 1 Transmit delay is 0, network state Backup, priority 1 Hello interval 1, dead interval 4, wait time 4, retransmit interval 5 Designated router 10.1.0.10, backup designated router 10.1.0.1 Hello packets received 1830, sent 1830, errors 0 Database Description packets received 4, sent 3,rxmt 0, errors 0 LS Request packets received 1, sent 1, rxmt 0, errors 0 LS Update packets received 29, sent 19, rxmt 0, errors 0 LS Acknowledgment packets received 19, sent 29, errors 0 Neighbor count is 1, adjacent neighbor count is 1 Interface br0, admin state UP, link state UP IP address 10.0.0.1/24, MTU 1500 Router ID 192.168.1.22, network type BROADCAST, cost 1 Transmit delay is 0, network state DROther, priority 1 Hello interval 1, dead interval 4, wait time 4, retransmit interval 5 Designated router 10.0.0.10, backup designated router 10.0.0.11 Hello packets received 3660, sent 1830, errors 0 Database Description packets received 8, sent 6, rxmt 0, errors 0 LS Request packets received 2, sent 2, rxmt 0, errors 0 LS Update packets received 50, sent 8, rxmt 0, errors 0 LS Acknowledgment packets received 62, sent 50, errors 0 Neighbor count is 2, adjacent neighbor count is 2 Router#
SHOW IP OSPF NEIGHBOR:
Display OSPF Neighbor Information.
show IP OSPF Neighbor
Example:
Router#Show IP OSPF Neighbor Area 2, network 10.2.0.1/24, network state Backup Router ID Priority State Dead Time Address Interface 10.2.0.10 1 Full/DR 3 10.2.0.10 br2 Area 1, network 10.1.0.1/24, network state Backup Router ID Priority State Dead Time Address Interface 10.1.0.10 1 Full/DR 3 10.1.0.10 br1 Area 0, network 10.0.0.1/24, network state DROther Router ID Priority State Dead Time Address Interface 10.0.11.1 1 Full/DR 3 10.0.0.10 br0 10.0.12.1 1 Full/BDR 3 10.0.0.11 br0 rcp#
SHOW IP OSPF ROUTE:
Display OSPF route information.
Show IP OSPF ROute [ecmp]
Example:
Router#Show IP OSPF Route C 10.0.0.0/24 [1] is directly connected, br0, area 0 O 10.0.3.0/24 [4] via 10.0.0.11, area 0 O 10.0.11.0/24 [2] via 10.0.0.10, area 0 O 10.0.12.0/24 [2] via 10.0.0.11, area 0 O 10.0.21.0/24 [3] via 10.0.0.10, area 0 O 10.0.22.0/24 [3] via 10.0.0.11, area 0 O E2 10.0.40.0/24 [20] via 10.0.0.10, area 0 O E1 10.0.41.0/24 [23] via 10.0.0.11, area 0 C 10.1.0.0/24 [1] is directly connected, br1, area 1 C 10.2.0.0/24 [1] is directly connected, br2, area 2 Router#
TIMERS SPF:
Specify The Delay Of Shortest Path First (SPF) Calculation After A Topology Change Is Detected.
[no] timers spf <delay>
The No Form Of The Command Sets The Default Value Of 5 Seconds.
Example:
Router(Config)#Router OSPF Router(OSPF)#Timers SPF 1 Router(OSPF)#
SUMMARY-ADDRESS:
Summarize External Routes.
summary-address <CIDR range> [not-advertise]
no summary-address <CIDR range>
where:
<CIDR range> - Range Of Addresses To Be Summarized.
Not-Advertise - Suppress Type 3 Summary LSA Generation.
The no Form Of The Command Will Remove The Summarization.
Example:
Router(Config)#Router OSPF Router(OSPF)#Summary-Address 1.2.3.0/24 not-advertise Router(OSPF)#
CONCLUSION:
The Goal Of This Article Is To Give An Easy Way To Understand The “Detailed OSPF Interface Output OSPF Terms And OSPF Configuration And Troubleshooting OSPF Commands References” And Also We Hope This Guide Will Help Every Beginner Who Are Going To Start Cisco Lab Practice Without Any Doubts. Some Topics That You Might Want To Pursue On Your Own That We Did Not Cover In This Article Are Listed Here!Hands - On Experience Is An Invaluable Part Of Preparing For The Lab Exam And Never Pass Up An Opportunity To Configure Or Troubleshoot A Router ( If You Have Access To Lab Facilities, Take Full Advantage Of Them) There Is No Replacement For The Experience You Can Gain From Working In A Lab, Where You Can Configure Whatever You Want To Configure And Introduce Whatever Problems You Want To Introduce, Without Risk Of Disrupting A Production Network. Thank You And Best Of Luck
This Article Written Author By: Premakumar Thevathasan - CCNA, CCNP, MCSE, MCSA, MCSA - MSG, CIW Security Analyst, CompTIA Certified A+ And Etc.
WARNING AND DISCLAIMER:
Routers Direct And Control Much Of The Data Flowing Across Computer Networks. This Guide Provides Technical Guidance Intended To Help All Network Students, Network Administrators And Security Officers Improve Of Their Demonstrated Ability To Achieve Specific objectives Within Set Timeframes.This Document Carries No Explicit Or Implied Warranty. Nor Is There Any Guarantee That The Information Contained In This Document Is Accurate. Every Effort Has Been Made To Make All Articles As Complete And As Accurate As Possible, But No Warranty Or Fitness Is Implied.
It Is Offered In The Hopes Of Helping Others, But You Use It At Your Own Risk. The Author Will Not Be Liable For Any Special, Incidental, Consequential Or Indirect Any Damages Due To Loss Of Data Or Any Other Reason That Occur As A Result Of Using This Document. But No Warranty Or Fitness Is Implied. The Information Provided Is On An "As Is" Basic. All Use Is Completely At Your Own Risk.
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