Mpls Nsn Training Day 3 Ospf

OSPF (Open Shortest Path first)

Mitrabh Shukla

National IP Manager

2 © Nokia Siemens Networks MPLS / Mitrabh Shukla

For internal use

Agenda

What is a Link State Protocol?

How Does OSPF Work?

How Do I Scale OSPF?

What Are Some Tips for Deployment?

How Do I Configure OSPF?

How Do I Verify OSPF ?


For internal use

Why Is It Called a Link State Protocol?

specific link characteristics and state information


For internal use

Link State Protocol Operation

Topology Information Is

Kept in a Database

Separate from the Routing

Table

A

B

C

2

13

13

Q

Z

X

X’s Link State

Z

X

YQ

Z’s Link State

Q’s Link State


For internal use

Advantages of a Link State Protocol

Uses costs to calculate path

Typically displays faster convergence than distance vector routing protocols

Typically more scalable due to hierarchical nature


For internal use

OSPF Benefits

Uses metrics—path cost

Support for CIDR, VLSM, authentication, multipath, and IP unnumbered

Relatively low, steady state bandwidth requirements


For internal use

OSPF History

Development began 1987 by IETF

OSPFv2 established in 1991 with RFC 1247

Goal—a link state protocol more efficient and scaleable than RIP

Latest revision is RFC 2328 April 1998


For internal use

Agenda


How Does OSPF Work?


What are some tips for Deployment?

How do I configure OSPF?

How do I verify OSPF ?


For internal use

OSPF Functions and Definitions

The high-level function of OSPF is

• Discover neighbors and form adjacencies

• Flood Link State Database (LSDB) information

• Compute the shortest path

• Install routes in route forwarding table

This section expands on these functions

Some definitions are needed first

• (See text on the page with this slide)


For internal use

Let’s exchange information

Discovering Adjacent Neighbors

Discover neighbors with Hello packets

Form Adjacencies with appropriate neighbors

Exchange Link State Database (LSDB) information using Link State Advertisements (LSA)

Hello, I’m B

Hello, I’m A

RID A RID B

I know about these links…

OK

I know about these links…


For internal use

Adjacency States

Sample Log showing adjacency processP1R1(config-router)#log-adjacency-changes detail

6d04h: %OSPF-5-ADJCHG: Process 100, Nbr 10.131.63.251 on

FastEthernet0/0 from DOWN to INIT, Received Hello


FastEthernet0/0 from INIT to 2WAY, 2-Way Received


FastEthernet0/0 from 2WAY to EXSTART, AdjOK?


FastEthernet0/0 from EXSTART to EXCHANGE, Negotiation Done


FastEthernet0/0 from EXCHANGE to LOADING, Exchange Done


FastEthernet0/0 from LOADING to FULL, Loading Done


For internal use

Propagate changes to maintain Link State Database synchronization

Flooding can impact performance in large nets

Keep LSDB small!

Flooding Link State Advertisements

Animated


For internal use

Computing the Shortest Path Tree

The optimal path is determined by thesum of the interface costs: Cost = 108/BW

10

192.213.11.0

222.211.10.0

128.213.0.0

8

10

5

5

10

5

192.213.11.0

222.211.10.0

128.213.0.0

10

10

10

5

5

0

5

Actual Network Shortest Path Tree


For internal use

Routing TableUpdated

Routing Table

Dijkstra Algorithm

Link State Database

Router 2, Area 1

LSA

ACK

Router 1, Area 1

When a Link Changes State

Every router in an area hears a specific link LSA

Each router computes shortest path routing table


For internal use

OSPF Areas

Area 10

RIP/RIPv2 World

Area 0

Area 11

Area 12

Area is a group of contiguous hosts and networks

Each area has a topology database

• Invisible outside the area

• Reduction in routing traffic

Backbone area must be contiguous

• All other areas must connect to the backbone

Virtual Links

Area 13


For internal use

What Are Virtual Links?

All areas must connect to area 0.0.0.0

Not recommended — So what’s it for?

• Tunnel ABR summaries to area 0

• Allow areas to connect to areas other than 0

• Repair a discontinuous area 0 (for example, if two companies merge and have backbones)

AREA 20AREA 10 AREA 0


For internal use

Router Types and Location

Autonomous System Boundary Routers

(ASBR) bordering a ―non-OSPF‖ area

Area Border Routers

Between areasRIP/RIPv2

Network

Area 10

Area 0

Area 11

Area 12

Area 13

Internal Router (IR)

Inside an area

Backbone Router (BR)

Inside the core


For internal use

0 1 2 3

0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

VERSION | TYPE | LENGTH

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

ROUTER ID

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

AREA ID

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

CHECKSUM | AuTYPE

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

AUTHENTICATION

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

DATA

+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+

OSPF Routing Protocol Packets

Share a common protocol header

Routing protocol packets are sent withtype of service (TOS) of 0

5 types of routing protocol packets (see text)


For internal use

Common Types of Link State Advertisements (LSAs)

Router link (LSA type 1)

Network link (LSA type 2)

Network summary (LSA type 3)

ASBR Summary (LSA type 4)

External (LSA type 5)

NSSA external (LSA type 7)


For internal use

Opaque Link State Advertisements (LSAs)

RFC 2370

• Used for distribution for applications

Opaque link-local (LSA type 9)

Opaque area-local (LSA type 10)

• First Cisco implementation with RSVP

Opaque AS (LSA type 11)

• Similar to type 5


For internal use

RIP Network

Simplified Example of Different LSAs

RIP Network

Area 10

Area 0

Area 11

External (type 5)

ASBR IR

ABR

ASBR

ABR

DR

ABR Summary (type 3)

IR ABR IR

Router link (type 1)

IR IR

External

ASBRExternal (type 7)

ASBR IR

(only in NSSA)

Animated

Network link (type 2)

DR IR

ASBR Summary (type 4)

ABR IR (about ASBR)ASBR

Note: only one example of each LSA type

exchange is demonstrated in this graphic


For internal use

DRBDR

DRBDR

Multi-Access Media

Gig/Fast/Ethernet, FDDI, Token Ring

Multicast

DR and BDR for each network


For internal use

Uses IP Multicast for Sending/Receiving Updates

On Broadcast networks

• DR and BDR —> AllSPFRouters (224.0.0.5)

• All other routers —> AllDRRouters (224.0.0.6)

Hello packets sent to All SPFRouters (Unicast on point-to-point and virtual links)


For internal use

Agenda


How Does OSPF Work?






For internal use

Backbone

Router

Using Areas

Area 1

Area 4

Area 0

Area 2 Area 3

Internal

Router

Area

Border

Router

Autonomous

System (AS)

Border Router

Internet


For internal use

Regular Area Flooding

Backbone Area 0

x.x.x.1

2.x.x.x

3.x.x.x

External

X.X.X.1

TokenRing

TokenRing

3.3.4.0

3.3.4.0

3.3.3.0

3.3

.1.0

2.2.4.0

2.2.4.0

2.2.3.0

2.2

.1.0

TokenRing

TokenRing

TokenRing

TokenRing

1.1.4.0

1.1.4.0

1.1.3.0

1.1

.1.0

x.x.x.1

1.x.x.x

2.x.x.x

x.x.x.1

1.x.x.x

3.x.x.x

ASBR

x.x.x.1


For internal use

Stub Area Flooding

Backbone Area 0

Default

2.x.x.x

3.x.x.x

External

X.X.X.1

TokenRing

TokenRing

3.3.4.0

3.3.4.0

3.3.3.0

3.3

.1.0

2.2.4.0

2.2.4.0

2.2.3.0

2.2

.1.0

TokenRing

TokenRing

TokenRing

TokenRing

1.1.4.0

1.1.4.0

1.1.3.0

1.1

.1.0

x.x.x.1

1.x.x.x

2.x.x.x

x.x.x.1

1.x.x.x

3.x.x.x

ASBR

x.x.x.1


For internal use

Totally Stubby Area Flooding

Backbone Area 0

Default

External

X.X.X.1

TokenRing

TokenRing

3.3.4.0

3.3.4.0

3.3.3.0

3.3

.1.0

2.2.4.0

2.2.4.0

2.2.3.0

2.2

.1.0

TokenRing

TokenRing

TokenRing

TokenRing

1.1.4.0

1.1.4.0

1.1.3.0

1.1

.1.0

x.x.x.1

1.x.x.x

2.x.x.x

x.x.x.1

1.x.x.x

3.x.x.x

ASBR

x.x.x.1

area x stub no-summary

area x stub


For internal use

Not So Stubby Areas (NSSA) Flooding

Backbone Area 0

External

X.X.X.1

TokenRing

TokenRing

3.3.4.0

3.3.4.0

3.3.3.0

3.3

.1.0

2.2.4.0

2.2.4.0

2.2.3.0

2.2

.1.0

TokenRing

TokenRing

TokenRing

TokenRing

1.1.4.0

1.1.4.0

1.1.3.0

1.1

.1.0

Default

x.x.x.1

x.x.x.2

1.x.x.x

2.x.x.x

Default

x.x.x.1

x.x.x.2

1.x.x.x

3.x.x.x

ASBR

x.x.x.1

External

X.X.X.2

x.x.x.2

x.x.x.2

LSA Type

Default must be

manually configured

Default

2.x.x.x

3.x.x.x


For internal use

Summarization

Route summarization is the consolidation of advertised addresses

Instead of advertising many specific prefixes, advertise only one summary prefix

• Area range command on ABR to summarize type 3 LSAs

• Summary-address command on ASBR to summarize type 5 LSAs

LSDB is smaller and more stable

Drawback is possible suboptimal routing


For internal use

Inter-Area Route Summarization - Area Range

ABRs will advertise networks in one area into another area

By default ABRs do not always summarize routes between areas

Advertise a summary route that covers as many individual networks within the area as possible (requires good address design)

On the ABR (Summarizes routes before injecting them into different area)

• Router(config-router)#area <area-id> range<network-address> <subnet-mask>


For internal use

External Route Summarization - summary-address

Each route, redistributed into OSPF from other protocols, is advertised individually with an external link state advertisement (LSA)

To reduce the size of the OSPF link state database configure a summary for external routes that are covered by a specified network address and mask

On the ASBR only (Summarizes external routes before injecting them into the OSPF domain)

• Router(config-router)# summary-address <network-address> <subnet-mask>


For internal use

Not Summarized: Specific Links

Backbone

Area 0

2.2.2.0

2.2.3.0

2.2

.1.0

TokenRing

TokenRing

1.1

.1.0

1.1.2.0 1.1.3.0

TokenRing

1.1.4.0

TokenRing

TokenRing

TokenRing 3.3.4.0

3.3.4.0

3.3.3.0

3.3

.1.0

1.1.1.0

1.1.2.0

1.1.3.0

1.1.4.0

3.3.1.0

3.3.2.0

3.3.3.0

3.3.4.0

2.2.1.0

2.2.2.0

2.2.3.0

Normal LSA flooding across area boundaries

Link state changes propagate out


For internal use

2.2.2.0

2.2.3.0

2.2

.1.0

TokenRing

TokenRing

Summarized: Summary Links

Only summary LSA flooding across area boundaries

Link-state changes NOT propagated out

Backbone

Area 0

1.1

.1.0

1.1.2.0 1.1.3.0

TokenRing

1.1.4.0

TokenRing

TokenRing

TokenRing 3.3.4.0

3.3.4.0

3.3.3.0

3.3

.1.0

1.0.0.0

2.0.0.0

3.0.0.0


For internal use

Area 0If R1 and R1 advertise the 11.1/16 subnet into area 0, suboptimal routing could occur

Use the area range command and divide the /16 into two /17s

Configure on Both ABRs

• area 10 range 11.1.0 /17

area 10 range 11.1.128 /17

Cost to Range 1:

• Via ABR1: 30 (R1-R3-R5) Via ABR2: 60 (R2-R4-R5)

Cost to Range 2:

• Via ABR1: 60 (R1-R3-R6) Via ABR2: 30 (R2-R4-R6)

11.1/16

ABR1 ABR2

10

505020 20

11.1.1/24

11.1.2/24 11.1.130/24

11.1.129/24

10

Preventing Suboptimal Summarization

R6

Area 10R4

R2R1

R3

R5

Range 2Range 1


For internal use

Area 3

network 131.108.0.0

subnets 49-63

range 255.255.240.0

Area 1

network 131.108.0.0

subnets 17-31

range 255.255.240.0

Area 2

network 131.108.0.0

subnets 33-47

range 255.255.240.0

Area 0

network 192.117.49.0

range 255.255.255.0

Addressing

Assign contiguous ranges of subnets per area to facilitate summarization


For internal use

Agenda


How Does OSPF Work?



How do I configure OSPF?

How do I verify OSPF ?


For internal use

IP Backbone

USA

FranceGermany

Japan

OSPF 1

BGP 1

Brazil Canada

OSPF 1

BGP 1

OSPF 1

BGP 1OSPF 1

BGP 1

OSPF 1

BGP 1

OSPF 1

BGP 1OSPF 1

BGP 1

Service Provider Deployment Characteristics

SPs will have only one instance of IGP running throughout network

BGP carries external reachability

No Redistribution


For internal use

Service Provider OSPF Features

OSPF features ISPs should consider

• OSPF logging neighbor changes

• OSPF reference cost

• OSPF Router ID Command

• OSPF Process Clear/Restart

• OSPF Authentication


For internal use

Agenda


How Does OSPF Work?






For internal use

Configure OSPF Steps

Configure OSPF Process

• Enable OSPF routing, which places you in router configuration mode

– router OSPF process-id

Define networks to advertise

• Network Statement or Redistribution

Configure OSPF Interfaces


For internal use

OSPF - Adding Networks(Specific Network Statements)

Specific network statements

• Every interface participating in OSPF requires a network statement

– router OSPF 100

– network 192.168.1.1 0.0.0.3 area 51

– network 192.168.1.5 0.0.0.3 area 51


For internal use

OSPF - Adding Networks(Redistribution)

redistribute connected subnets

• Works for all connected interfaces on the router but networks are not summarized

– router OSPF 100

– redistribute connected subnets

Not recommended


For internal use

Router Sub-commands

NETWORK <n.n.n.n> <mask> AREA <area-id>

AREA <area-id> STUB {no-summary}

AREA <area-id> AUTHENTICATION

AREA <area-id> DEFAULT_COST <cost>

AREA <area-id> VIRTUAL-LINK <router-id>...

AREA <area-id> RANGE <address mask>


For internal use

OSPF - Passive Interface

For interfaces that should not participate in OSPF set them as passive

– router OSPF 100

– passive-interface Serial 1/0


For internal use

OSPF - Default Passive Interface

Sets all interfaces as passive by default

Activate interfaces that need to have adjacencies set

• router OSPF 100

• passive-interface default

• no passive-interface POS 4/0


For internal use

OSPF - Virtual Links

The virtual link is between router ID 1.1.1.1 and router ID 2.2.2.2

on router 1.1.1.1 – area 10 virtual-link 2.2.2.2

on router 2.2.2.2

• area 10 virtual-link 1.1.1.1

AREA 20AREA 0AREA 10


For internal use

Interface Subcommands

IP OSPF COST <cost>

IP OSPF PRIORITY <8-bit-number>

IP OSPF HELLO-INTERVAL <number-of-seconds>

IP OSPF DEAD-INTERVAL <number-of-seconds>

IP OSPF AUTHENTICATION-KEY <8-bytes-of-password>


For internal use

Agenda


How Does OSPF Work?






For internal use

Verify Configuration

P1R1#show ip protocols

Routing Protocol is "ospf 100"

Outgoing update filter list for all interfaces is not set

Incoming update filter list for all interfaces is not set

Router ID 10.131.31.251

It is an area border router

Number of areas in this router is 2. 2 normal 0 stub 0 nssa

Maximum path: 4

Routing for Networks:

10.131.31.224 0.0.0.3 area 0

10.131.31.228 0.0.0.3 area 110

10.131.31.240 0.0.0.3 area 0

10.131.31.251 0.0.0.0 area 0

10.131.255.224 0.0.0.3 area 0

Passive Interface(s):

Ethernet2/0

Ethernet3/0

Loopback0

Routing Information Sources:

Gateway Distance Last Update

10.131.31.251 110 00:00:13

Distance: (default is 110)


For internal use

OSPF Verification (Routes)

Are routes getting old?

• show ip route

• OSPF routes should get old

Is the number of routes stable?

• If you have the luxury, fail a link, allow the network to converge then restore the link and let the network converge

– Are convergence times appropriate for the protocol

– Remember to account for differentials in convergence time


For internal use

show ip route ospf

P1R1#show ip route ospf

10.0.0.0/8 is variably subnetted, 24 subnets, 4 masks

O IA 10.131.63.254/32 [110/31] via 10.131.31.226, 2d19h, E1/0

O IA 10.131.63.252/32 [110/21] via 10.131.31.226, 2d19h, E1/0

O IA 10.131.63.253/32 [110/31] via 10.131.31.226, 2d19h, E1/0

O 10.131.63.251/32 [110/11] via 10.131.31.226, 2d19h, E1/0

O IA 10.131.63.228/30 [110/20] via 10.131.31.226, 2d19h, E1/0

O 10.131.63.224/30 [110/20] via 10.131.31.226, 2d19h, E1/0

O IA 10.131.63.236/30 [110/30] via 10.131.31.226, 2d19h, E1/0

O IA 10.131.63.232/30 [110/30] via 10.131.31.226, 2d19h, E1/0

O 10.131.31.254/32 [110/21] via 10.131.31.230, 2d19h, E0/0

O 10.131.31.252/32 [110/11] via 10.131.31.230, 2d19h, E0/0

O IA 10.131.31.253/32 [110/21] via 10.131.31.230, 2d19h, E0/0

O 10.131.31.236/30 [110/20] via 10.131.31.230, 2d19h, E0/0

O IA 10.131.31.232/30 [110/20] via 10.131.31.230, 2d19h, E0/0

O 10.131.223.240/30 [110/20] via 10.131.31.226, 2d19h, E1/0

AGE


For internal use

OSPF Verification (neighbors)

Do I have all the neighbors I should have?

Are neighbors in the ―FULL‖ state?

P1R1#show ip ospf neighbor

Neighbor ID Pri State Dead Time Address Interface

10.131.63.251 1 FULL/DR 00:00:37 10.131.31.226 E1/0

10.131.31.252 1 FULL/DR 00:00:31 10.131.31.230 E0/0


For internal use

Other OSPF Show Commands

show ip OSPF

show ip OSPF interface

show ip OSPF database

show ip OSPF virtual-links

show ip OSPF border-routers

show ip OSPF flood-list

show ip OSPF request-list

show ip OSPF retransmission-list

show ip OSPF summary-address


For internal use

show ip ospf (1 of 2)

P1R1#sh ip ospf

Routing Process "ospf 100" with ID 10.131.31.251

Supports only single TOS(TOS0) routes

Supports opaque LSA

It is an area border router

SPF schedule delay 5 secs, Hold time between two SPFs 10 secs

Minimum LSA interval 5 secs. Minimum LSA arrival 1 secs

LSA group pacing timer 240 secs

Interface flood pacing timer 33 msecs

Retransmission pacing timer 66 msecs

Number of external LSA 0. Checksum Sum 0x000000

Number of opaque AS LSA 0. Checksum Sum 0x000000

Number of DCbitless external and opaque AS LSA 0

Number of DoNotAge external and opaque AS LSA 0

Number of areas in this router is 2. 2 normal 0 stub 0 nssa

External flood list length 0


For internal use

show ip ospf (2 of 2)

Area BACKBONE(0)

Number of interfaces in this area is 5

Area has no authentication

SPF algorithm executed 5 times

Area ranges are

Number of LSA 27. Checksum Sum 0x0D12B3

Number of opaque link LSA 0. Checksum Sum 0x000000

Number of DCbitless LSA 0

Number of indication LSA 0

Number of DoNotAge LSA 14

Flood list length 0

Area 110

Number of interfaces in this area is 1

Area has no authentication

SPF algorithm executed 4 times

Area ranges are

Number of LSA 38. Checksum Sum 0x126275

Number of opaque link LSA 0. Checksum Sum 0x000000

Number of DCbitless LSA 0

Number of indication LSA 0

Number of DoNotAge LSA 0

Flood list length 0


For internal use

show ip OSPF interface

P1R1#show ip OSPF interface

Ethernet2/0 is up, line protocol is up

Internet Address 10.131.255.226/30, Area 0

PID 100, Router ID 10.131.31.251, Net Type BROADCAST, Cost: 10

Transmit Delay is 1 sec, State DR, Priority 1

Designated Router (ID) 10.131.31.251, address 10.131.255.226

No backup designated router on this network

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

No Hellos (Passive interface)

Index 5/6, flood queue length 0

Next 0x0(0)/0x0(0)

Last flood scan length is 0, maximum is 0

Last flood scan time is 0 msec, maximum is 0 msec

Neighbor Count is 0, Adjacent neighbor count is 0

Suppress hello for 0 neighbor(s)

Loopback0 is up, line protocol is up

Internet Address 10.131.31.251/32, Area 0

PID 100, Router ID 10.131.31.251, Net Type LOOPBACK, Cost: 1

Loopback interface is treated as a stub Host

===========================snip===============================


For internal use

show ip OSPF database

P1R1#show ip OSPF database

OSPF Router with ID (10.131.31.251) (Process ID 100)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link

count

10.131.31.251 10.131.31.251 1872 0x80000060 0x00DF2F 5

10.131.31.252 10.131.31.252 1 (DNA) 0x80000002 0x00B0E3 1

===========================snip==============================Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum

10.131.31.226 10.131.63.251 107 0x8000005F 0x0040D4

Summary Net Link States (Area 0)


10.131.31.228 10.131.31.251 1872 0x80000060 0x00F0AB

10.131.31.228 10.131.31.252 5 (DNA) 0x80000001 0x00A951

===========================snip==============================Summary ASB Link States (Area 0)


10.131.31.252 10.131.31.251 1876 0x8000005E 0x00087A

10.131.63.252 10.131.63.251 110 0x8000005F 0x00C37D

Continues with other areas


For internal use

show ip OSPF virtual-links

P1R1#show ip OSPF virtual-links

Virtual Link OSPF_VL0 to router 10.131.31.252 is up

Run as demand circuit

DoNotAge LSA allowed.

Transit area 110, via interface Ethernet0/0, Cost of using 10

Transmit Delay is 1 sec, State POINT_TO_POINT,

Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5

Hello due in 00:00:06

Adjacency State FULL (Hello suppressed)

Index 2/3, retransmission queue length 0, number of retransmission

2

First 0x0(0)/0x0(0) Next 0x0(0)/0x0(0)

Last retransmission scan length is 1, maximum is 1

Last retransmission scan time is 0 msec, maximum is 0 msec


For internal use

Chapter Summary

You should now be able to:

Describe the functional characteristics of OSPF

Discuss OSPF scalability practices

Configure basic OSPF routing

Configure OSPF areas

Verify OSPF functionality


For internal use

show ip OSPF flood-list

P1R1#show ip OSPF flood-list


Interface Ethernet2/0, Queue length 0

Interface Loopback0, Queue length 0





For internal use

show ip OSPF request-list

P1R1#show ip OSPF request-list


Neighbor 10.131.63.251, interface E1/0 address 10.131.31.226

Type LS ID ADV RTR Seq NO Age Checksum


Type LS ID ADV RTR Seq NO Age Checksum


For internal use

show ip OSPF retransmission-list

P1R1#show ip OSPF retransmission-list





For internal use

show ip OSPF summary-address

P1R1#show ip OSPF summary-address

OSPF Process 100, Summary-address

Not configured


For internal use

show ip OSPF border-routers

P1R1#show ip OSPF border-routers

OSPF Process 100 internal Routing Table

Codes: i - Intra-area route, I - Inter-area route

i 10.131.63.251 [10] via 10.131.31.226, E1/0, ABR, Area 0, SPF 5

i 10.131.63.252 [20] via 10.131.31.226, E1/0, ABR/ASBR, Area 0, SPF 5



Documents

Mpls Nsn Training Day 3 Ospf