JUNOSのOSPF_その1
まずは簡単なやつ
構成は↓
R1-R8まで、エリア0でやってみる。
CiscoについてはR3のみでJuniperに関してはR5のみ
<R3>
interface Loopback0
ip address 1.1.1.3 255.255.255.255
ip ospf network point-to-point
ip ospf 1 area 0
!
interface GigabitEthernet2
ip address 172.16.4.1 255.255.255.0
ip ospf 1 area 0
!
interface GigabitEthernet3
ip address 172.16.2.254 255.255.255.0
ip ospf 1 area 0
!
interface GigabitEthernet4
ip address 172.16.5.1 255.255.255.0
ip ospf 1 area 0
!
router ospf 1
router-id 1.1.1.3
!
そして、R5
<R5>
set interfaces ge-0/0/0 unit 0 family inet address 172.16.7.1/24
set interfaces ge-0/0/1 unit 0 family inet address 172.16.8.1/24
set interfaces ge-0/0/2 unit 0 family inet address 172.16.5.254/24
set interfaces lo0 unit 0 family inet address 2.1.1.5/32
set protocols ospf area 0.0.0.0 interface ge-0/0/0.0
set protocols ospf area 0.0.0.0 interface ge-0/0/1.0
set protocols ospf area 0.0.0.0 interface ge-0/0/2.0
set protocols ospf area 0.0.0.0 interface lo0.0
set routing-options graceful-restart
router-id 2.1.1.5;
そして、Cisco&Juniperは物理IFはpoint-to-pointを入れてないので、DR/BDRの選出あり
R3の状態確認
R3#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
2.1.1.5 128 FULL/DR 00:00:37 172.16.5.254 GigabitEthernet4
1.1.1.1 1 FULL/BDR 00:00:38 172.16.2.1 GigabitEthernet3
1.1.1.4 1 FULL/DR 00:00:36 172.16.4.254 GigabitEthernet2
R3#
JuniperのデフォルトPriorityは128なので、何もしないとJuniper側がDR
では、R6を以下に設定
set interfaces ge-0/0/0 unit 0 family inet address 172.16.7.254/24
set interfaces ge-0/0/1 unit 0 family inet address 172.16.9.254/24
set interfaces ge-0/0/2 unit 0 family inet address 172.16.6.1/24
set interfaces lo0 unit 0 disable
set interfaces lo0 unit 0 family inet address 2.1.1.6/32
set protocols ospf area 0.0.0.0 interface ge-0/0/0.0
set protocols ospf area 0.0.0.0 interface ge-0/0/1.0
set protocols ospf area 0.0.0.0 interface ge-0/0/2.0
set protocols ospf area 0.0.0.0 interface lo0.0
set routing-options graceful-restart
R6はRouter-id未設定&lo0はdisable
この状態でR5で見ると・・・
admin@R5> show ospf neighbor
Address Interface State ID Pri Dead
172.16.7.254 ge-0/0/0.0 Full 172.16.6.1 128 36
172.16.8.254 ge-0/0/1.0 Full 2.1.1.7 128 39
172.16.5.1 ge-0/0/2.0 Full 1.1.1.3 1 33
admin@R5> show ospf interface
Interface State Area DR ID BDR ID Nbrs
ge-0/0/0.0 BDR 0.0.0.0 172.16.6.1 2.1.1.5 1
ge-0/0/1.0 BDR 0.0.0.0 2.1.1.7 2.1.1.5 1
ge-0/0/2.0 DR 0.0.0.0 2.1.1.5 1.1.1.3 1
lo0.0 DR 0.0.0.0 2.1.1.5 0.0.0.0 0
Router-IDが想定と違う
念のため、R4のCiscoでも確認
R4#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
172.16.6.1 128 FULL/DR 00:00:35 172.16.6.1 GigabitEthernet4
1.1.1.2 1 FULL/BDR 00:00:38 172.16.3.254 GigabitEthernet3
1.1.1.3 1 FULL/DR 00:00:34 172.16.4.1 GigabitEthernet2
CiscoではOSPFのルータID選出時は
「手動のrouter-id」→「UPのloopBackの最大アドレス」→「UPの物理アドレスが大きいもの」という順番だったはず。
勘違いかも?ってことで、R2に以下を入れて確認
interface Loopback0
ip address 1.1.1.2 255.255.255.255
ip ospf network point-to-point
ip ospf 1 area 0
shutdown
!
interface GigabitEthernet1
ip address 192.168.2.202 255.255.255.0
!
interface GigabitEthernet2
ip address 172.16.1.254 255.255.255.0
ip ospf 1 area 0
!
interface GigabitEthernet3
ip address 172.16.3.254 255.255.255.0
ip ospf 1 area 0
!
router ospf 1
!
loopbackをshutし、OSPFが有効ではないGi2を作って、Roter-IDを削除
この状態でR4で確認
R4#show ip ospf neighbor
Neighbor ID Pri State Dead Time Address Interface
172.16.6.1 128 FULL/DR 00:00:36 172.16.6.1 GigabitEthernet4
192.168.2.202 1 FULL/BDR 00:00:36 172.16.3.254 GigabitEthernet3
1.1.1.3 1 FULL/BDR 00:00:37 172.16.4.1 GigabitEthernet2
やはり、認識はあっていた
けれどもJuniperはそうではない模様なので、調べてみた
The router identifier is used by OSPF to identify the routing device from which a packet originated. Junos OS selects a router identifier according to the following set of rules
1.By default, Junos OS selects the lowest configured physical IP address of an interface as the router identifier.2.If a loopback interface is configured, the IP address of the loopback interface becomes the router identifier.
3.If multiple loopback interfaces are configured, the lowest loopback address becomes the router identifier.
4.If a router identifier is explicitly configured using the router-id address statement under the [edit routing-options] hierarchy level, the above three rules are ignored.
router-idがなければ、Loopbackの最小アドレス、それがなければ物理IFの最小アドレスとなる模様。
ここは想定していなかったので一旦終わり
やはり実機で確認してよかった。。