OSPF Network( Broadcast / Point-to-Point ) Cisco IOS-XR

概要

Cisco IOS-XRにてOSPFのNetowrk(Broadcast / Point-to-Point )の設定方法を紹介します。

Broadcast/Point-to-Pointの違い

: OSPF ネットワークタイプ

設定概要図

Network Type Broadcast

インターフェイスがイーサネットの時はデフォルトの動作がBroadcastです。従って特別の設定は不要です。

OSPFの設定後、インターフェイスの状態を確認すると「Network Type BROADCAST」の記載があり、Broadcastで動作していることがわかります。
また、Broadcastで動作しているので、DR,BDRの選出が動作します。今回のインターフェイスでは、DRに選出されていることがわかります。

RP/0/0/CPU0:IOSXR-R1#show ospf interface gigabitEthernet 0/0/0/0
Wed Apr 18 04:07:26.577 UTC

GigabitEthernet0/0/0/0 is up, line protocol is up
  Internet Address 192.168.0.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1
  Transmit Delay is 1 sec, State DR, Priority 1, MTU 1500, MaxPktSz 1500
  Designated Router (ID) 1.1.1.1, Interface address 192.168.0.1
  Backup Designated router (ID) 2.2.2.2, Interface address 192.168.0.2
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:04:833
  Index 2/2, flood queue length 0
  Next 0(0)/0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  LS Ack List: current length 0, high water mark 1
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2  (Backup Designated Router)
  Suppress hello for 0 neighbor(s)
  Multi-area interface Count is 0
RP/0/0/CPU0:IOSXR-R1#

RP/0/0/CPU0:IOSXR-R1#show ospf interface gigabitEthernet 0/0/0/0

Wed Apr 18 04:07:26.577 UTC

GigabitEthernet0/0/0/0 is up, line protocol is up

Internet Address 192.168.0.1/24, Area 0

Process ID 1, Router ID 1.1.1.1, Network Type BROADCAST, Cost: 1

Transmit Delay is 1 sec, State DR, Priority 1, MTU 1500, MaxPktSz 1500

Designated Router (ID) 1.1.1.1, Interface address 192.168.0.1

Backup Designated router (ID) 2.2.2.2, Interface address 192.168.0.2

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

Hello due in 00:00:04:833

Index 2/2, flood queue length 0

Next 0(0)/0(0)

Last flood scan length is 1, maximum is 1

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

LS Ack List: current length 0, high water mark 1

Neighbor Count is 1, Adjacent neighbor count is 1

Adjacent with neighbor 2.2.2.2 (Backup Designated Router)

Suppress hello for 0 neighbor(s)

Multi-area interface Count is 0

RP/0/0/CPU0:IOSXR-R1#

Broadcastで動作しているので、該当のネットワーク（192.168.0.0/24)では、DRであるIOSXR-R1ルータから「LSA Type2 Network」が生成されていることがわかります。

RP/0/0/CPU0:IOSXR-R1#show ospf database
Wed Apr 18 04:08:33.143 UTC


            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         582         0x80000002 0x000e32 2
2.2.2.2         2.2.2.2         583         0x80000002 0x00fd35 2

                Net Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum
192.168.0.1     1.1.1.1         582         0x80000001 0x004c73
RP/0/0/CPU0:IOSXR-R1#show ospf database network
Wed Apr 18 04:08:35.383 UTC


            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Net Link States (Area 0)

  Routing Bit Set on this LSA
  LS age: 584
  Options: (No TOS-capability, DC)
  LS Type: Network Links
  Link State ID: 192.168.0.1 (address of Designated Router)
  Advertising Router: 1.1.1.1
  LS Seq Number: 80000001
  Checksum: 0x4c73
  Length: 32
  Network Mask: /24
        Attached Router: 1.1.1.1
        Attached Router: 2.2.2.2

RP/0/0/CPU0:IOSXR-R1#

RP/0/0/CPU0:IOSXR-R1#show ospf database

Wed Apr 18 04:08:33.143 UTC

OSPF Router with ID (1.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count

1.1.1.1 1.1.1.1 582 0x80000002 0x000e32 2

2.2.2.2 2.2.2.2 583 0x80000002 0x00fd35 2

Net Link States (Area 0)

Link ID ADV Router Age Seq# Checksum

192.168.0.1 1.1.1.1 582 0x80000001 0x004c73

RP/0/0/CPU0:IOSXR-R1#show ospf database network

Wed Apr 18 04:08:35.383 UTC

OSPF Router with ID (1.1.1.1) (Process ID 1)

Net Link States (Area 0)

Routing Bit Set on this LSA

LS age: 584

Options: (No TOS-capability, DC)

LS Type: Network Links

Link State ID: 192.168.0.1 (address of Designated Router)

Advertising Router: 1.1.1.1

LS Seq Number: 80000001

Checksum: 0x4c73

Length: 32

Network Mask: /24

Attached Router: 1.1.1.1

Attached Router: 2.2.2.2

RP/0/0/CPU0:IOSXR-R1#

Network Type Point-to-Point

設定方法

network NET-WORK-TYPE

1	network NET-WORK-TYPE

コマンド引数	説明
NET-WORK-TYPE	OSPFのネットワークタイプを設定する。設定項目として下記がある broadcast non-broadcast point-to-multipoint point-to-point

構成図を元に設定例

IOSXR-R1

router ospf 1
 area 0
  interface gigabitEthernet 0/0/0/0
   network point-to-point

router ospf 1

area 0

interface gigabitEthernet 0/0/0/0

network point-to-point

IOSXR-R2

router ospf 1
 area 0
  interface gigabitEthernet 0/0/0/0
   network point-to-point

router ospf 1

area 0

interface gigabitEthernet 0/0/0/0

network point-to-point

設定後のインターフェイスおよびOSPF Databaseの変化について

設定後、インターフェイスの状態を確認すると「Network Type POINT_TO_POINT」の記載があり、Point-to-Pointで動作していることがわかります。
また、Point-to-Pointで動作しているので、DR,BDRの選出はありません。従ってDR,BDRの項目がなくなっていることがわかります。

RP/0/0/CPU0:IOSXR-R1#show ospf interface gigabitEthernet 0/0/0/0
Wed Apr 18 04:12:19.647 UTC

GigabitEthernet0/0/0/0 is up, line protocol is up
  Internet Address 192.168.0.1/24, Area 0
  Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1
  Transmit Delay is 1 sec, State POINT_TO_POINT, MTU 1500, MaxPktSz 1500
  Timer intervals configured, Hello 10, Dead 40, Wait 40, Retransmit 5
    Hello due in 00:00:01:946
  Index 2/2, flood queue length 0
  Next 0(0)/0(0)
  Last flood scan length is 1, maximum is 1
  Last flood scan time is 0 msec, maximum is 0 msec
  LS Ack List: current length 0, high water mark 2
  Neighbor Count is 1, Adjacent neighbor count is 1
    Adjacent with neighbor 2.2.2.2
  Suppress hello for 0 neighbor(s)
  Multi-area interface Count is 0
RP/0/0/CPU0:IOSXR-R1#

RP/0/0/CPU0:IOSXR-R1#show ospf interface gigabitEthernet 0/0/0/0

Wed Apr 18 04:12:19.647 UTC

GigabitEthernet0/0/0/0 is up, line protocol is up

Internet Address 192.168.0.1/24, Area 0

Process ID 1, Router ID 1.1.1.1, Network Type POINT_TO_POINT, Cost: 1

Transmit Delay is 1 sec, State POINT_TO_POINT, MTU 1500, MaxPktSz 1500

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

Hello due in 00:00:01:946

Index 2/2, flood queue length 0

Next 0(0)/0(0)

Last flood scan length is 1, maximum is 1

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

LS Ack List: current length 0, high water mark 2

Neighbor Count is 1, Adjacent neighbor count is 1

Adjacent with neighbor 2.2.2.2

Suppress hello for 0 neighbor(s)

Multi-area interface Count is 0

RP/0/0/CPU0:IOSXR-R1#

NetworkTypeがPoint-to-Pointになった為、LSAは「Type-1 Router」のみになりました。

RP/0/0/CPU0:IOSXR-R1#show ospf database
Wed Apr 18 04:13:01.614 UTC


            OSPF Router with ID (1.1.1.1) (Process ID 1)

                Router Link States (Area 0)

Link ID         ADV Router      Age         Seq#       Checksum Link count
1.1.1.1         1.1.1.1         58          0x80000004 0x002cfa 3
2.2.2.2         2.2.2.2         59          0x80000004 0x00c954 3
RP/0/0/CPU0:IOSXR-R1#

RP/0/0/CPU0:IOSXR-R1#show ospf database

Wed Apr 18 04:13:01.614 UTC

OSPF Router with ID (1.1.1.1) (Process ID 1)

Router Link States (Area 0)

Link ID ADV Router Age Seq# Checksum Link count

1.1.1.1 1.1.1.1 58 0x80000004 0x002cfa 3

2.2.2.2 2.2.2.2 59 0x80000004 0x00c954 3

RP/0/0/CPU0:IOSXR-R1#

Cisco IOS XR 設定方法記事一覧

IOS XRの特徴

基本設定

Cisco IOS-XR 基本設定 ( ホスト名、インターフェイスなど）

OSPF

BGP

BGP基本設定

OSPF Network( Broadcast / Point-to-Point ) Cisco IOS-XR

概要

Broadcast/Point-to-Pointの違い

OSPF ネットワークタイプ

設定概要図

Network Type Broadcast

Network Type Point-to-Point

設定方法

構成図を元に設定例

IOSXR-R1

IOSXR-R2

設定後のインターフェイスおよびOSPF Databaseの変化について

Cisco IOS XR 設定方法記事一覧

基本設定

OSPF

BGP