LAGに所属するポートのVLAN設定について(EOS,IOSXE,Nexusの違い) - NETCON lv1-8

問題の解説がCiscoの挙動と違うようなので検証した。

疑問: port-channelにメンバポートを組み入れる際、メンバポートのVLANはpo側に合わせないといけないのではないか？

結論:

• Arista cEOSではメンバポートの設定VLANではなくpoのVLAN設定が使われる。
• Cisco IOSXEではメンバポートとpoのVLAN設定が異なると、メンバポートがsuspendになる
• Cisco NXOSではメンバポートとpoのVLAN設定が異なると、コマンドが入らない

共通設定

RT1, RT2間をeth1,2の2本のLinkでつなぐ。poをvlan100として、メンバをvlan200,300としておき、各ルータのvlan 100同士でpingが飛ぶかを確認。図はIOS-XEの例。

cEOSでの検証

環境はContainerLab上の EOS 4.33.1.1F

Config

vlan 100,200,300
!
interface Port-Channel10
   switchport trunk allowed vlan 100
   switchport mode trunk
   port-channel min-links 2
!
interface Ethernet1
   switchport trunk allowed vlan 200
   switchport mode trunk
   channel-group 10 mode active
!
interface Ethernet2
   switchport trunk allowed vlan 300
   switchport mode trunk
   channel-group 10 mode active
!
interface Vlan100
   ip address 192.168.0.1/24
   ! RT2側は0.2

結果

ceos1#ping 192.168.0.2 repeat 1
PING 192.168.0.2 (192.168.0.2) 72(100) bytes of data.
80 bytes from 192.168.0.2: icmp_seq=1 ttl=64 time=2.69 ms

show vlan

ceos1#show vlan
1     default                          active
100   VLAN0100                         active    Cpu, Po10
200   VLAN0200                         active
300   VLAN0300                         active

Cisco IOS-XE

CML2のIOSXE 17.15.1

Config

vlan 100,200,300
!
interface Port-channel10
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 100
 switchport mode trunk
!
interface Ethernet0/1
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 200
 switchport mode trunk
 channel-group 10 mode active
!
interface Ethernet0/2
 switchport trunk encapsulation dot1q
 switchport trunk allowed vlan 300
 switchport mode trunk
 channel-group 10 mode active
!
interface Vlan100
 ip address 192.168.0.1 255.255.255.0
 ! RT2は192.168.0.2

表示

*Feb  1 15:29:17.763: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel10, changed state to down
*Feb  1 15:29:42.658: %ETC-5-CANNOT_BUNDLE2: Et0/1 is not compatible with Po10 and will be suspended (vlan mask is different)
*Feb  1 15:29:42.658: %ETC-5-CANNOT_BUNDLE2: Et0/2 is not compatible with Po10 and will be suspended (vlan mask is different)

結果: NG

rt1#ping 192.168.0.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.0.2, timeout is 2 seconds:
.....

show int: 以下のようにpoに参加できずsuspendになる。

rt1#show int status
Port         Name               Status       Vlan       Duplex  Speed Type
Et0/1                           suspended    trunk        full   auto 10/100/1000BaseTX
Et0/2                           suspended    trunk        full   auto 10/100/1000BaseTX
Po10                            notconnect   1            full   auto 10/100/1000BaseTX

show etherchannel

rt1#show etherchannel 10 summary
        I - stand-alone s - suspended
10     Po10(SD)        LACP        Et0/1(s)        Et0/2(s)

直す。両方でconfig修正。

int range eth 0/1-2
 switchport trunk allowed vlan 100

入れた瞬間のlog

*Feb  1 15:36:24.999: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/1, changed state to up
*Feb  1 15:36:24.999: %LINEPROTO-5-UPDOWN: Line protocol on Interface Ethernet0/2, changed state to up
*Feb  1 15:36:28.847: %LINK-5-UPDOWN: Interface Port-channel10, changed state to up
*Feb  1 15:36:29.847: %LINEPROTO-5-UPDOWN: Line protocol on Interface Port-channel10, changed state to up

結果

rt1#ping 192.168.0.2
Type escape sequence to abort.
Sending 5, 100-byte ICMP Echos to 192.168.0.2, timeout is 2 seconds:
.!!!!

NX-OS

そもそもvlan設定が違うと入らない。

(config-if)# interface port-channel10
(config-if)#   switchport
(config-if)#   switchport mode trunk
(config-if)#   switchport trunk allowed vlan 100
(config)# int eth 1/33
(config-if)#    switchport
(config-if)#    switchport trunk allowed vlan 200
(config-if)#    switchport mode trunk
(config-if)#    channel-group 10 mode active
Command failed: Port not compatible
  Port allowed VLAN list : Port-channel VLAN list doesn't match the interface VLAN list

合わせると入る。

(config-if)#  int eth 1/33
(config-if)#   switchport trunk allowed vlan 100
(config-if)# channel-group 10 mode active
(config-if)#