2024-11-03 Cat9000V GIR 機能検証

提供:hkatou_Lab
2024年11月3日 (日) 12:05時点におけるHkatou (トーク | 投稿記録)による版

Nexus で採用され Catalyst 9000 から実装された GIR について、機能検証を実施しました。

このページにラボシナリオとして、コンフィグや確認コマンド、疎通確認のポイントなどをまとめています。

検証対象として Catalyst 9000V Q200 を使用していますが、実機の Catalyst 9000 シリーズでも同様の動作をするはずです。

目的

GIR の動作について理解を深められること。

通信要件

GIR : BGP / OSPF / HSRP

  • GIR を開始したホストを経路迂回すること
  • GIR を停止したホストに経路復旧すること

検証環境

Cisco Catalyst 9000V Q200 : IOS-XE 17.12.1 x6

構成図

  • Catalyst 3850 : PE01 , CE01 , CE02 , CORE01 , CORE02 , CPE01

PE01 を WAN の機器、CE01 , CE02 , CORE01 , CORE02 , CPE を LAN の機器とする。

 
20241103 GIR Diagram

IP アドレッシング

文書用例示アドレス (8.8.8.8 を除く)
大種別 小種別 ネットワーク アドレス ホスト インターフェース ホスト アドレス 備考
グローバルアドレス WAN グローバルアドレス 203.0.113.128/30 PE01 Gi1/0/1 203.0.113.129/30 BGP でデフォルトルートを広報
CE01 Gi1/0/23 203.0.113.130/30 PE ルータからデフォルトルートを受信
203.0.113.132/30 PE01 Gi1/0/1 203.0.113.133/30 BGP でデフォルトルートを広報
CE02 Gi1/0/23 203.0.113.134/30 PE ルータからデフォルトルートを受信
198.51.100.0/24 PE01 Lo0 198.51.100.1/32 上り方向 ping の宛先
LAN グローバル アドレス CE01 Lo0 198.51.100.11/32 iBGP ピア用
CE02 Lo0 198.51.100.12/32 iBGP ピア用
CORE01 Lo0 198.51.100.21/32
CORE02 Lo0 198.51.100.22/32
203.0.113.128/25 CE01 Po21 203.0.113.137/30 CE01 <-> CE02 間わたり OSPF P2P リンク

迂回経路用

CE02 Po21 203.0.113.138/30
CE01 Gi1/0/1 203.0.113.141/30 CE01 <-> CORE01 間 OSPF P2P リンク
CORE01 Gi1/0/23 203.0.113.142/30
CE02 Gi1/0/2 203.0.113.145/30 CE02 <-> CORE02 間 OSPF P2P リンク
CORE02 Gi1/0/24 203.0.113.146/30
CE01 Po21 203.0.113.149/30 CORE01 <-> CORE02 間 OSPF P2P リンク

迂回経路用

CE02 Po21 203.0.113.150/30
203.0.113.0/25 CE01 Vlan1 203.0.113.2/25

HSRP .1

CPE 収容 SVI
CE02 Vlan1 203.0.113.3/25

HSRP .1

CPE 収容 SVI
CPE Vlan1 203.0.113.101/25 CPE01 用ホストアドレス
プライベートアドレス LAN プライベート アドレス なし

コンフィギュレーション

ここではプロトコル・ホスト別にコンフィギュレーションを簡単に解説します。

自分でコンフィグを組んでみたい人向けに、デフォルトでは表示しません。

PE01

PE01 コンフィグ
プロトコル PE01 コンフィグ 解説
eBGP
PE01#show run | s back0|net1/0/[1-2]$|router bgp|ip route 0

interface Loopback0
 ip address 198.51.100.1 255.255.255.255

interface GigabitEthernet1/0/1
 description CE01_Gi1/0/23
 no switchport
 ip address 203.0.113.129 255.255.255.252

interface GigabitEthernet1/0/2
 description CE02_Gi1/0/23
 no switchport
 ip address 203.0.113.133 255.255.255.252

router bgp 64496
 bgp router-id 198.51.100.1
 bgp log-neighbor-changes
 bgp deterministic-med
 timers bgp 10 30
 neighbor 203.0.113.130 remote-as 64512
 neighbor 203.0.113.130 description CE01
 neighbor 203.0.113.130 default-originate
 neighbor 203.0.113.130 soft-reconfiguration inbound
 neighbor 203.0.113.134 remote-as 64512
 neighbor 203.0.113.134 description CE02
 neighbor 203.0.113.134 default-originate
 neighbor 203.0.113.134 soft-reconfiguration inbound

ip route 0.0.0.0 0.0.0.0 Null0 254
CE01 , 02 と eBGP ピアを張るための設定

CE01 , 02

CE01 , 02 コンフィグ
プロトコル CE01 コンフィグ CE02 コンフィグ 解説
eBGP
CE01#show run | s back0|net1/0/23$|^router bgp|route-map

interface Loopback0
 ip address 198.51.100.11 255.255.255.255

interface GigabitEthernet1/0/23
 description PE01_Gi1/0/1
 no switchport
 ip address 203.0.113.130 255.255.255.252

router bgp 64512
 bgp router-id 198.51.100.11
 bgp log-neighbor-changes
 bgp deterministic-med
 network 203.0.113.0 mask 255.255.255.128
 timers bgp 10 30
 neighbor 198.51.100.12 remote-as 64512
 neighbor 198.51.100.12 description CE02
 neighbor 198.51.100.12 update-source Loopback0
 neighbor 198.51.100.12 next-hop-self
 neighbor 198.51.100.12 soft-reconfiguration inbound
 neighbor 203.0.113.129 remote-as 64496
 neighbor 203.0.113.129 description PE01
 neighbor 203.0.113.129 soft-reconfiguration inbound
 neighbor 203.0.113.129 route-map LP300 in
 neighbor 203.0.113.129 route-map MED100 out

route-map LP300 permit 10
 set local-preference 300

route-map MED100 permit 10
 set metric 100
CE02#show run | s back0|net1/0/23$|^router bgp|route-map

interface Loopback0
 ip address 198.51.100.12 255.255.255.255

interface GigabitEthernet1/0/23
 description PE01_Gi1/0/2
 no switchport
 ip address 203.0.113.134 255.255.255.252

router bgp 64512
 bgp router-id 198.51.100.12
 bgp log-neighbor-changes
 bgp deterministic-med
 network 203.0.113.0 mask 255.255.255.128
 timers bgp 10 30
 neighbor 198.51.100.11 remote-as 64512
 neighbor 198.51.100.11 description CE01
 neighbor 198.51.100.11 update-source Loopback0
 neighbor 198.51.100.11 next-hop-self
 neighbor 198.51.100.11 soft-reconfiguration inbound
 neighbor 203.0.113.133 remote-as 64496
 neighbor 203.0.113.133 description PE01
 neighbor 203.0.113.133 soft-reconfiguration inbound
 neighbor 203.0.113.133 route-map LP100 in
 neighbor 203.0.113.133 route-map MED300 out

route-map MED300 permit 10
 set metric 300

route-map LP100 permit 10
 set local-preference 100
PE01 と eBGP ピア、

CE01 と CE02 で iBGP ピアを 張るコンフィグ route-map LP300 LP300 で上りトラフィックを優先する 値が高いほうが優先 route-map MED100 MED100 で下りトラフィックを優先する 値が低いほうが優先

OSPF
CE01#show run | s net1/0/1$|net1/0/2[1-2]$|el21|^router ospf

interface Port-channel21
 description CE02_Po21
 no switchport
 ip address 203.0.113.137 255.255.255.252
 ip ospf network point-to-point
 ip ospf cost 100

interface GigabitEthernet1/0/1
 description CORE01_Gi1/0/23
 no switchport
 ip address 203.0.113.141 255.255.255.252
 ip ospf network point-to-point
 ip ospf cost 1

interface GigabitEthernet1/0/21
 description CE02_Gi1/0/21
 no switchport
 no ip address
 channel-group 21 mode active

interface GigabitEthernet1/0/22
 description CE02_Gi1/0/22
 no switchport
 no ip address
 channel-group 21 mode active

router ospf 1
 router-id 198.51.100.11
 passive-interface default
 no passive-interface GigabitEthernet1/0/1
 no passive-interface Port-channel21
 network 198.51.100.11 0.0.0.0 area 0.0.0.0
 network 203.0.113.136 0.0.0.3 area 0.0.0.0
 network 203.0.113.140 0.0.0.3 area 0.0.0.0
 default-information originate metric 1 metric-type 1
CE02#show run | s net1/0/2$|net1/0/2[1-2]$|el21|^router ospf

interface Port-channel21
 description CE01_Po21
 no switchport
 ip address 203.0.113.138 255.255.255.252
 ip ospf network point-to-point
 ip ospf cost 100

interface GigabitEthernet1/0/2
 description CORE02_Gi1/0/24
 no switchport
 ip address 203.0.113.145 255.255.255.252
 ip ospf network point-to-point
 ip ospf cost 40

interface GigabitEthernet1/0/21
 description CE01_Gi1/0/21
 no switchport
 no ip address
 channel-group 21 mode active

interface GigabitEthernet1/0/22
 description CE01_Gi1/0/22
 no switchport
 no ip address
 channel-group 21 mode active

router ospf 1
 router-id 198.51.100.12
 passive-interface default
 no passive-interface GigabitEthernet1/0/2
 no passive-interface Port-channel21
 network 198.51.100.12 0.0.0.0 area 0.0.0.0
 network 203.0.113.144 0.0.0.3 area 0.0.0.0
 network 203.0.113.128 0.0.0.127 area 0.0.0.0
 default-information originate metric 100 metric-type 1
CE01 , 02 間

CE01 , 02 <-> CORE01 , 02 間 OSPF iBGP で使用する Loopback を広報する

GIR
CE01#show run | s mainte
maintenance-template BGP_OSPF
 router bgp 64512
 router ospf 1
system mode maintenance
 timeout 15
 template BGP_OSPF
 failsafe 5
CE02#show run | s mainte
maintenance-template BGP_OSPF
 router bgp 64512
 router ospf 1
system mode maintenance
 timeout 15
 template BGP_OSPF
 failsafe 5
CORE01 , 02 コンフィグ
種別 CORE01 コンフィグ CORE02 コンフィグ 解説
OSPF
CORE01#show run | s net1/0/2[1-2]$|el21|^router ospf

interface Port-channel21
 description CORE02_Po21
 no switchport
 ip address 203.0.113.149 255.255.255.252
 ip ospf network point-to-point
 ip ospf cost 50

interface GigabitEthernet1/0/21
 description CORE02_Gi1/0/21
 no switchport
 no ip address
 channel-group 21 mode active

interface GigabitEthernet1/0/22
 description CORE02_Gi1/0/22
 no switchport
 no ip address
 channel-group 21 mode active

router ospf 1
 router-id 198.51.100.21
 passive-interface default
 no passive-interface GigabitEthernet1/0/23
 no passive-interface Port-channel21
 network 198.51.100.21 0.0.0.0 area 0.0.0.0
 network 203.0.113.0 0.0.0.127 area 0.0.0.0
 network 203.0.113.140 0.0.0.3 area 0.0.0.0
 network 203.0.113.148 0.0.0.3 area 0.0.0.0
CORE02#show run | s net1/0/2[1-2]$|el21|^router ospf

interface Port-channel21
 description CORE01_Po21
 no switchport
 ip address 203.0.113.150 255.255.255.252
 ip ospf network point-to-point
 ip ospf cost 50

interface GigabitEthernet1/0/21
 description CORE01_GI1/0/21
 no switchport
 no ip address
 channel-group 21 mode active

interface GigabitEthernet1/0/22
 description CORE01_GI1/0/22
 no switchport
 no ip address
 channel-group 21 mode active

router ospf 1
 router-id 198.51.100.22
 passive-interface default
 no passive-interface GigabitEthernet1/0/24
 no passive-interface Port-channel21
 network 198.51.100.22 0.0.0.0 area 0.0.0.0
 network 203.0.113.0 0.0.0.127 area 0.0.0.0
 network 203.0.113.144 0.0.0.3 area 0.0.0.0
 network 203.0.113.148 0.0.0.3 area 0.0.0.0
HSRP
CORE01#show run | s net1/0/1$|Vlan1$
interface GigabitEthernet1/0/1
 description CPE01_Gi1/0/23
 switchport mode access
 switchport nonegotiate
 spanning-tree portfast
 spanning-tree bpdufilter enable

interface Vlan1
 ip address 203.0.113.2 255.255.255.128
 standby version 2
 standby 1 ip 203.0.113.1
 standby 1 priority 110
 standby 1 preempt
CORE02#show run | s net1/0/1$|Vlan1$
interface GigabitEthernet1/0/1
 description CPE01_Gi1/0/24
 switchport mode access
 switchport nonegotiate
 spanning-tree portfast
 spanning-tree bpdufilter enable

interface Vlan1
 ip address 203.0.113.3 255.255.255.128
 standby version 2
 standby 1 ip 203.0.113.1
 standby 1 priority 105
 standby 1 preempt
GIR
CORE01#show run | s mainte
maintenance-template OSPF_HSRP
 router ospf 1
 hsrp Vlan1 1

system mode maintenance
 timeout 15
 template OSPF_HSRP
 failsafe 5
CORE02#show run | s mainte
maintenance-template OSPF_HSRP
 router ospf 1
 hsrp Vlan1 1

system mode maintenance
 timeout 15
 template OSPF_HSRP
 failsafe 5
CPE01 コンフィグ
種別 CPE01 コンフィグ 解説
ホスト
CPE01#show run | s net1/0/2[3-4]|Vlan1|ip route 0

interface GigabitEthernet1/0/23
 description CORE01_Gi1/0/1
 switchport mode access
 switchport nonegotiate
 spanning-tree portfast
 spanning-tree bpdufilter enable

interface GigabitEthernet1/0/24
 description CORE02_Gi1/0/1
 switchport mode access
 switchport nonegotiate
 spanning-tree portfast
 spanning-tree bpdufilter enable

interface Vlan1
 ip address 203.0.113.101 255.255.255.128

ip route 0.0.0.0 0.0.0.0 203.0.113.1

疎通・経路確認

コマンドリスト

PE01

PE01#ping 203.0.113.101
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 203.0.113.101, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 70/87/103 ms
PE01#
PE01#traceroute 203.0.113.101
Type escape sequence to abort.
Tracing the route to 203.0.113.101
VRF info: (vrf in name/id, vrf out name/id)
  1 203.0.113.130 40 msec 40 msec 38 msec
  2 203.0.113.142 81 msec 54 msec 61 msec
  3 203.0.113.101 [AS 64512] 103 msec *  105 msec

通常時は CE01 -> CORE01 -> CPE01 を経由します。

PE01#show ip bgp
BGP table version is 11, local router ID is 198.51.100.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
              t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
      0.0.0.0          0.0.0.0                                0 i
 *>   203.0.113.0/25   203.0.113.130          100             0 64512 i
 *                     203.0.113.134          300             0 64512 i

CE01 宛を優先させています。

CORE01

CORE01#show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "ospf 1", distance 110, metric 2, candidate default path
  Tag 1, type extern 1
  Last update from 203.0.113.141 on GigabitEthernet1/0/23, 00:01:20 ago
  Routing Descriptor Blocks:
  * 203.0.113.141, from 198.51.100.11, 00:01:20 ago, via GigabitEthernet1/0/23
      Route metric is 2, traffic share count is 1
      Route tag 1
CORE01#
CORE01#show standby brief
                     P indicates configured to preempt.
                     |
Interface   Grp  Pri P State   Active          Standby         Virtual IP
Vl1         1    110 P Active  local           203.0.113.3     203.0.113.1

OSPF メトリック 1 と HSRP Priority 110 で優先させています。

CPE01

CPE01#ping 198.51.100.1
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.51.100.1, timeout is 2 seconds:
!!!!!
Success rate is 100 percent (5/5), round-trip min/avg/max = 77/87/109 ms
CPE01#
CPE01#traceroute 198.51.100.1
Type escape sequence to abort.
Tracing the route to 198.51.100.1
VRF info: (vrf in name/id, vrf out name/id)
  1 203.0.113.2 40 msec 41 msec 72 msec
  2 203.0.113.141 63 msec 66 msec 69 msec
  3 203.0.113.129 89 msec *  84 msec

通常時は CORE01 -> CE01 -> PE01 を経由します。

CE01 GIR BGP + OSPF 動作確認

start maintenance でホストを Remove します。

CE01#start maintenance
Template BGP_OSPF will be applied. Do you want to continue?[confirm]
CE01#
Nov  3 2024 00:43:52 UTC: %MMODE-6-MMODE_SNAPSHOT_CREATE_ENTER_MMODE: Generating current snapshot 'before_maintenance'
Nov  3 2024 00:43:52 UTC: %MMODE-6-MMODE_CLIENT_TRANSITION_START: Maintenance Isolate start for router bgp 64512
Nov  3 2024 00:44:23 UTC: %MMODE-6-MMODE_CLIENT_TRANSITION_COMPLETE: Maintenance Isolate complete for router bgp 64512
Nov  3 2024 00:44:23 UTC: %MMODE-6-MMODE_CLIENT_TRANSITION_START: Maintenance Isolate start for router ospf 1
Nov  3 2024 00:44:53 UTC: %MMODE-6-MMODE_CLIENT_TRANSITION_COMPLETE: Maintenance Isolate complete for router ospf 1
Nov  3 2024 00:44:53 UTC: %MMODE-6-MMODE_ISOLATED: System is in Maintenance
CE01 BGP + OSPF GIR 動作確認
確認 通常時 CE01 メンテナンス時 備考
BGP
PE01#traceroute 203.0.113.101
Type escape sequence to abort.
Tracing the route to 203.0.113.101
VRF info: (vrf in name/id, vrf out name/id)
  1 203.0.113.130 39 msec 65 msec 37 msec
  2 203.0.113.142 66 msec 75 msec 67 msec
  3 203.0.113.101 [AS 64512] 94 msec *  94 msec
PE01#show ip bgp
BGP table version is 13, local router ID is 198.51.100.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
              t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
      0.0.0.0          0.0.0.0                                0 i
 *>   203.0.113.0/25   203.0.113.130          100             0 64512 i
 *                     203.0.113.134          300             0 64512 i
PE01#traceroute 203.0.113.101
Type escape sequence to abort.
Tracing the route to 203.0.113.101
VRF info: (vrf in name/id, vrf out name/id)
  1 203.0.113.134 50 msec 30 msec 35 msec
  2 203.0.113.146 57 msec 67 msec 67 msec
  3 203.0.113.101 [AS 64512] 125 msec *  135 msec
PE01#
PE01#show ip bgp
BGP table version is 8, local router ID is 198.51.100.1
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
              t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
      0.0.0.0          0.0.0.0                                0 i
 *>   203.0.113.0/25   203.0.113.134          300             0 64512 i
上り : CPE01

CORE01 はわたりを経由するように変更されています。 下り : PE01 PE01 は CE02 を経由するように変更されています。 CE01 は BGP アドレス広報を停止していました。

CE01(maint-mode)#show ip bgp summary
BGP router identifier 198.51.100.11, local AS number 64512
BGP table version is 20, main routing table version 20
2 network entries using 496 bytes of memory
5 path entries using 680 bytes of memory
5/2 BGP path/bestpath attribute entries using 1480 bytes of memory
1 BGP AS-PATH entries using 24 bytes of memory
0 BGP route-map cache entries using 0 bytes of memory
0 BGP filter-list cache entries using 0 bytes of memory
BGP using 2680 total bytes of memory
1 received paths for inbound soft reconfiguration
BGP activity 5/3 prefixes, 22/17 paths, scan interval 60 secs
2 networks peaked at 08:12:51 Nov 3 2024 JST (03:45:55.560 ago)

Neighbor        V           AS MsgRcvd MsgSent   TblVer  InQ OutQ Up/Down  State/PfxRcd
198.51.100.12   4        64512     153     160       20    0    0 00:22:50        2
203.0.113.129   4        64496     155     159       20    0    0 00:23:14        1
CE01(maint-mode)#show ip bgp
BGP table version is 20, local router ID is 198.51.100.11
Status codes: s suppressed, d damped, h history, * valid, > best, i - internal,
              r RIB-failure, S Stale, m multipath, b backup-path, f RT-Filter,
              x best-external, a additional-path, c RIB-compressed,
              t secondary path, L long-lived-stale,
Origin codes: i - IGP, e - EGP, ? - incomplete
RPKI validation codes: V valid, I invalid, N Not found

     Network          Next Hop            Metric LocPrf Weight Path
 * i  0.0.0.0          198.51.100.12            0    100      0 64496 i
 *>                    203.0.113.129                 300      0 64496 i
 * i  203.0.113.0/25   198.51.100.12           41    100      0 i
 *>                    203.0.113.142        65536         32768 i
OSPF
CE02#show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "ospf 1", distance 110, metric 81, candidate default path
  Tag 1, type extern 1
  Last update from 203.0.113.137 on Port-channel21, 00:00:20 ago
  Routing Descriptor Blocks:
  * 203.0.113.137, from 198.51.100.11, 00:00:20 ago, via Port-channel21
      Route metric is 81, traffic share count is 1
      Route tag 1
CE02#show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "bgp 64512", distance 20, metric 0, candidate default path
  Tag 64496, type external
  Last update from 203.0.113.133 00:00:07 ago
  Routing Descriptor Blocks:
  * 203.0.113.133, from 203.0.113.133, 00:00:07 ago
      opaque_ptr 0x7477AABBBCC0
      Route metric is 0, traffic share count is 1
      AS Hops 1
      Route tag 64496
      MPLS label: none
上り : CE02

通常時は CE01 宛わたり Po21 を向いていますが、CE01 GIR 中は PE01 宛 Gi1/0/23 を向いています。

CORE01#show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "ospf 1", distance 110, metric 2, candidate default path
  Tag 1, type extern 1
  Last update from 203.0.113.141 on GigabitEthernet1/0/23, 00:07:11 ago
  Routing Descriptor Blocks:
  * 203.0.113.141, from 198.51.100.11, 00:07:11 ago, via GigabitEthernet1/0/23
      Route metric is 2, traffic share count is 1
      Route tag 1


CORE01#show ip ospf 1 rib

            OSPF Router with ID (198.51.100.21) (Process ID 1)


                Base Topology (MTID 0)

OSPF local RIB
Codes: * - Best, > - Installed in global RIB

*>  198.51.100.11/32, Intra, cost 65536, area 0.0.0.0
      via 203.0.113.141, GigabitEthernet1/0/23
*>  198.51.100.12/32, Intra, cost 91, area 0.0.0.0
      via 203.0.113.150, Port-channel21
<snip>


CORE01#ping 198.51.100.11
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 198.51.100.11, timeout is 2 seconds:
!!!!!
 Success rate is 100 percent (5/5), round-trip min/avg/max = 19/25/35 ms
CORE01#show ip route 0.0.0.0
Routing entry for 0.0.0.0/0, supernet
  Known via "ospf 1", distance 110, metric 190, candidate default path
  Tag 1, type extern 1
  Last update from 203.0.113.150 on Port-channel21, 00:00:06 ago
  Routing Descriptor Blocks:
  * 203.0.113.150, from 198.51.100.12, 00:00:06 ago, via Port-channel21
      Route metric is 190, traffic share count is 1
      Route tag 1
上り : CORE01

CE01 の OSPF コスト メトリックが 65536 になっており、重くなっています。 疎通自体は可能です。

CPE01#traceroute 198.51.100.1
Type escape sequence to abort.
Tracing the route to 198.51.100.1
VRF info: (vrf in name/id, vrf out name/id)
  1 203.0.113.2 71 msec 73 msec 65 msec
  2 203.0.113.141 82 msec 53 msec 55 msec
  3 203.0.113.129 66 msec *  80 msec
CPE01#traceroute 198.51.100.1
Type escape sequence to abort.
Tracing the route to 198.51.100.1
VRF info: (vrf in name/id, vrf out name/id)
  1 203.0.113.2 37 msec 69 msec 38 msec
  2 203.0.113.150 93 msec 86 msec 88 msec
  3 203.0.113.145 109 msec 110 msec 111 msec
  4 203.0.113.133 213 msec *  154 msec
上り : CPE01

CORE01 のわたりを経由するようになりました。

動作確認 - ホスト別コマンドリスト

リファレンス

脚注