Cisco FlexLink

Overview

CiscoSystems IOS に実装されている FlexLink の動作を確認する。

Reference

Flex Link (CiscoSystems)

Flex Link Function

CiscoSystems社のドキュメントによれば FlexLink は下記の動作をする。

障害を検出
Primary Link で学習された Dynamic Unicast MAC Address を Standby Link に移行
Standby Link を Forwarding State に移行
新しい Active Interface 経由で Dummy Multicast Packet を送信

Check Point

FlexLink機能確認

上記のFlexLink動作の中で確認する事項は

SW01 で Dummy Multicast Packet の送信
SW02 で Dummy Multicast Packet の受信
SW02 で mac address-table で Host の MAC Address の Forward Interface の変化

である。

通信影響確認

FlexLinkによる通信経路切り替りによる通信の影響

Summary

結果

ここでは動作確認の結果を記載する。

Link down とほぼ同時にForwardingPortの切り替りとDummy Multicast Packetを送出
Catalyst2960S / 15.2(2)E9 の IOS では無通信のMAC Addressは15秒程度でmac address-tableから削除される現象が発生
PingのPacket Lossは1秒程度以内

となった。

再検証

また Dummy Multicast Packet を SW02 が受信した時の mac address-table の aging time の動作については別途、動作確認することとする。

Cisco Flex Link Dummy Multicast Packet MAC address aging time

Network Diagram

Environment

SW01 / SW02

Cisco IOS Software, C2960S Software (C2960S-UNIVERSALK9-M), Version 15.2(2)E9, RELEASE SOFTWARE (fc4)
Technical Support: http://www.cisco.com/techsupport
Copyright (c) 1986-2018 by Cisco Systems, Inc.
Compiled Sat 08-Sep-18 14:56 by prod_rel_team

ROM: Bootstrap program is C2960S board boot loader
BOOTLDR: C2960S Boot Loader (C2960S-HBOOT-M) Version 12.2(55r)SE, RELEASE SOFTWARE (fc1)

SW03 / SW04

Cisco IOS Software, C3750 Software (C3750-IPSERVICES-M), Version 12.2(35)SE2, RELEASE SOFTWARE (fc1)
Copyright (c) 1986-2007 by Cisco Systems, Inc.
Compiled Tue 06-Feb-07 01:27 by antonino
Image text-base: 0x00003000, data-base: 0x01240AEC

ROM: Bootstrap program is C3750 boot loader
BOOTLDR: C3750 Boot Loader (C3750-HBOOT-M) Version 12.2(25r)SEE4, RELEASE SOFTWARE (fc1)

PC

$ cat /etc/os-release
NAME="Ubuntu"
VERSION="18.04.4 LTS (Bionic Beaver)"
ID=ubuntu
ID_LIKE=debian
PRETTY_NAME="Ubuntu 18.04.4 LTS"
VERSION_ID="18.04"
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
VERSION_CODENAME=bionic
UBUNTU_CODENAME=bionic
$

Configuration

SW01

!
interface GigabitEthernet1/0/1
 switchport backup interface Gi1/0/2
 switchport backup interface Gi1/0/2 preemption mode forced
!
interface GigabitEthernet1/0/2
!
interface GigabitEthernet1/0/11
 switchport access vlan 2
!
!
interface Vlan1
 no ip address
 shutdown
!
interface Vlan2
 ip address 192.168.201.1 255.255.255.0
!
ip default-gateway 192.168.201.254
!
ntp server 192.168.1.10
!

SW02

!
interface GigabitEthernet1/0/1
!
interface GigabitEthernet1/0/2
!
interface GigabitEthernet1/0/11
 switchport access vlan 2
!
interface Vlan1
 ip address 192.168.202.2 255.255.255.0
!
interface Vlan2
 ip address 192.168.201.2 255.255.255.0
!
ip default-gateway 192.168.201.254
!
ntp server 192.168.1.10
!

SW03 / SW04

Default Configuration

MAC Address

f0de.f12e.f993 : PC NIC
c07b.bcbb.fcc0 : SW01 Interface vlan1

Methods

Function で記載した動作を確認するために

SW01 : console message で interface down / up を確認する
SW02 : PC NIC と SW01 interface vlan 1 の MAC Address の forwarding port が切り替わっていることを show mac address-table dynamic command で確認する
PC : 切替に伴う Ping の Packet Loss を確認する

以上の3点である。

Traffic off / Link down

SW01 : Link down

sw01#
Jul 11 15:17:39: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to down
Jul 11 15:17:40: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to down
sw01#

SW02 : mac address-table state

sw02#show mac address-table dynamic
Load for five secs: 5%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:17:21.127 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/1
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 6
sw02#
sw02#show mac address-table dynamic
Load for five secs: 8%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:17:40.128 JST Sat Jul 11 2020 <----- Link down とほぼ同時
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    c07b.bcbb.fcc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/2 <----- Interface切り替わり
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 7
sw02#
sw02#show mac address-table dynamic
Load for five secs: 12%/0%; one minute: 7%; five minutes: 6%
Time source is NTP, 15:17:53.718 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    c07b.bcbb.fcc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 7
sw02#show mac address-table dynamic
Load for five secs: 12%/0%; one minute: 7%; five minutes: 6%
Time source is NTP, 15:17:54.342 JST Sat Jul 11 2020 <----- 
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 5
sw02#

SW02 : mac address-table 保持時間

SW02 で Port の切り替り確認：15:17:40.128
SW02 で mac address-table から PC の MAC Addressが削除：15:17:54.342
経過時間：0:00:14.214

15秒程度で MAC Address Table から削除されている。

Traffic off / Link up

SW01 : Link up

sw01#
Jul 11 15:22:55: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to up
Jul 11 15:22:56: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to up
sw01#
Jul 11 15:23:28: %BACKUP_INTERFACE-5-PREEMPT: Preempting interface Gi1/0/2 in backup pair (Gi1/0/1, Gi1/0/2), preemption mode is forced
sw01#

SW02 : mac address-table state

sw02#show mac address-table dynamic
Load for five secs: 5%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:23:28.501 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 5
sw02#show mac address-table dynamic
Load for five secs: 5%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:23:29.381 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    c07b.bcbb.fcc0    DYNAMIC     Gi1/0/1
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/1 <----- 切り替り後
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 7
sw02#
中略
sw02#show mac address-table dynamic
Load for five secs: 6%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:23:43.685 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    c07b.bcbb.fcc0    DYNAMIC     Gi1/0/1
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/1
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 7
sw02#show mac address-table dynamic
Load for five secs: 6%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:23:44.660 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 5
sw02#

SW02 : mac address-table 保持時間

15:23:29.381 : SW02 で Port の切り替り確認
15:23:43.685 : SW02 で mac address-table から PC の MAC Addressが削除前
0:00:14.304 : 経過時間

15秒程度で MAC Address Table から削除されている。

Traffic on / Link down

SW01 : Link down

sw01#
Jul 11 15:31:36: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to down
Jul 11 15:31:37: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to down
sw01#

SW02 : mac address-table state

sw02#show mac address-table dynamic
Load for five secs: 5%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:31:38.478 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    c07b.bcbb.fcc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 7
sw02#
中略
sw02#show mac address-table dynamic
Load for five secs: 6%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:32:07.242 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 6
sw02#show mac address-table dynamic
Load for five secs: 6%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:32:07.855 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 5
sw02#

SW02 : mac address-table 保持時間

15:31:38.478 :

15:32:07.242 :

0:00:28.764 :

Ping

$ ping -c 100 -i 0.2 -w 0.8 192.168.202.2 | while read line; do echo `date +'%Y/%m/%d %H:%M:%S.%3N'` $line; done | tee -i pingt-linkdown.log
2020/07/11 15:31:32.134 PING 192.168.202.2 (192.168.202.2) 56(84) bytes of data.
2020/07/11 15:31:32.137 64 bytes from 192.168.202.2: icmp_seq=1 ttl=255 time=2.44 ms
2020/07/11 15:31:32.333 64 bytes from 192.168.202.2: icmp_seq=2 ttl=255 time=0.788 ms
中略
2020/07/11 15:31:34.951 64 bytes from 192.168.202.2: icmp_seq=15 ttl=255 time=1.96 ms
2020/07/11 15:31:35.150 64 bytes from 192.168.202.2: icmp_seq=16 ttl=255 time=0.681 ms
2020/07/11 15:31:35.760 64 bytes from 192.168.202.2: icmp_seq=19 ttl=255 time=1.51 ms
2020/07/11 15:31:35.961 64 bytes from 192.168.202.2: icmp_seq=20 ttl=255 time=1.77 ms
中略
2020/07/11 15:31:52.243 --- 192.168.202.2 ping statistics ---
2020/07/11 15:31:52.245 100 packets transmitted, 98 received, 2% packet loss, time 19909ms
2020/07/11 15:31:52.247 rtt min/avg/max/mdev = 0.681/1.852/5.746/1.021 ms
$

Traffic on / Link up

SW01 : Link Up

sw01#
Jul 11 15:40:34: %LINK-3-UPDOWN: Interface GigabitEthernet1/0/1, changed state to up
Jul 11 15:40:35: %LINEPROTO-5-UPDOWN: Line protocol on Interface GigabitEthernet1/0/1, changed state to up
sw01#
Jul 11 15:41:07: %BACKUP_INTERFACE-5-PREEMPT: Preempting interface Gi1/0/2 in backup pair (Gi1/0/1, Gi1/0/2), preemption mode is forced
sw01#

SW02 : mac address-table state

sw02#show mac address-table dynamic
Load for five secs: 7%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:41:06.965 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/2 <----- 切り替わり前
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 6
sw02#show mac address-table dynamic
Load for five secs: 7%/0%; one minute: 6%; five minutes: 6%
Time source is NTP, 15:41:07.726 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    c07b.bcbb.fcc0    DYNAMIC     Gi1/0/1
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/1 <----- 切り替わり後
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 7
sw02#
sw02#show mac address-table dynamic
Load for five secs: 9%/0%; one minute: 7%; five minutes: 6%
Time source is NTP, 15:41:34.256 JST Sat Jul 11 2020
          Mac Address Table
-------------------------------------------

Vlan    Mac Address       Type        Ports
----    -----------       --------    -----
   1    001b.5455.e902    DYNAMIC     Gi1/0/1
   1    0023.5dbd.4d82    DYNAMIC     Gi1/0/2
   1    0023.5dbd.4dc0    DYNAMIC     Gi1/0/2
   1    f0de.f12e.f993    DYNAMIC     Gi1/0/1
   2    c89c.1d24.2ae2    DYNAMIC     Gi1/0/11
   2    c89c.1d24.2ae5    DYNAMIC     Gi1/0/11
Total Mac Addresses for this criterion: 6
sw02#

SW02 : mac address-table 保持時間

15:41:06.965 : SW02 切り替え前を確認した時刻

15:41:07 : SW01 Link Down 時刻

15:41:07.726 : SW02 切り替えを確認した時刻

15:41:28.040：Ping の最後のPacket送信時刻

15:41:34.256 : mac address-table から削除されていることを確認した時刻

Ping

$ ping -c 300 -i 0.2 -w 0.8 192.168.202.2 | while read line; do echo `date +'%Y/%m/%d %H:%M:%S.%3N'` $line; done | tee -i pingt-linkup.log
2020/07/11 15:40:27.915 PING 192.168.202.2 (192.168.202.2) 56(84) bytes of data.
2020/07/11 15:40:27.917 64 bytes from 192.168.202.2: icmp_seq=1 ttl=255 time=1.43 ms
2020/07/11 15:40:28.116 64 bytes from 192.168.202.2: icmp_seq=2 ttl=255 time=1.81 ms
中略
2020/07/11 15:41:27.840 64 bytes from 192.168.202.2: icmp_seq=299 ttl=255 time=2.23 ms
2020/07/11 15:41:28.040 64 bytes from 192.168.202.2: icmp_seq=300 ttl=255 time=1.22 ms
2020/07/11 15:41:28.042
2020/07/11 15:41:28.044 --- 192.168.202.2 ping statistics ---
2020/07/11 15:41:28.046 300 packets transmitted, 300 received, 0% packet loss, time 60125ms
2020/07/11 15:41:28.049 rtt min/avg/max/mdev = 0.670/2.200/25.403/2.366 ms
$

Dummy Multicast Packet

Dummy Multicast Packet は Destination MAC Address = 01:00:0c:cd:cd:cd の Packet である。

Cisco IOS では良く利用される Packet である。

SW01 でInterface GigabitEthernet 1/0/1 から GigabitEthernet 1/0/2 への切り替り時のPacketをWiresharkでCaptureすると下記のPacketが記録される。

No.     Time           Source                Destination           Protocol Length Port   Info
     10 12.856470435   Cisco_bb:fc:c0        STP-UplinkFast        LLC      62            U, func=UI; SNAP, OUI 0x00000C (Cisco Systems, Inc), PID 0x0115
     11 12.856471297   Cisco_bb:fc:c0        STP-UplinkFast        ARP      62            Unknown ARP opcode 0x0115
     12 12.856473690   0115.fc               000c.bb               DDP      62     128    Unknown DDP protocol (17)
     13 12.856473994   000f0000.000000000000 0115bbfc.808017000014 IPX      62     0x0002 CISCO PING
     14 12.858636543   WistronI_2e:f9:93     STP-UplinkFast        LLC      62            U, func=UI; SNAP, OUI 0x00000C (Cisco Systems, Inc), PID 0x0115
     15 12.858637225   WistronI_2e:f9:93     STP-UplinkFast        ARP      62            Unknown ARP opcode 0x0115
     16 12.858637563   0115.00               000c.00               DDP      62     0      Unknown DDP protocol (00)
     17 12.858978256   00000000.000000000000 01150000.000000000000 IPX      62     0x0000 Unknown (0x0000)

Source MAC Address

c0:7b:bc:bb:fc:c0 : SW01 Interface Vlan1 MAC Address
f0:de:f1:2e:f9:93 : PC NIC MAC Address

Protocol

Result

Dummy Multicast Packet

SW02 で PC の MAC Address を Source Addressとする Dummy Multicast Packet を受信

mac address-table に保持される時間

通信がない場合

PC の MAC Address を Source Address とする通信が無い場合、SW02 の mac address-table は上記で学習した PC の MAC Address を15秒程度維持した後に mac address-table から削除される現象が発生

通信がある場合

上記の期間（時間内）に通信がある場合 mac address-table にPC の MAC Address を保持

Consideration

mac address-table に保持される時間

Dummy Multicast Packet で学習した MAC Address を保持する時間以上の間隔がある通信は Interface の切替によって通信が復元しない可能性がある。

上記の現象が発生した場合は送信元 Host Device の ARP Cache がクリアされ ARP Request(Broadcast) を送信するまで通信は不可となる。

Dummy Multicast Packet で学習した MAC Address を mac address-table の aging time の時間保持しない理由は不明である。

mac address-table move update transmit/receive command

CiscoSystems社のDocumentやその他のWebサイトでは下記のcommandを設定する旨の記載があるが、本検証では特に設定することなく Dummy Multicast Packet を送受信している。

mac address-table move update transmit
mac address-table move update receive

機能実装・利用

FlexLink は CiscoSystems社の独自実装の機能である。本検証で利用した IOS や機器以外で同様の動作をするのかは不明であり、利用する Hardware / Software で動作を確認して利用することを推奨する。

Switch

Cisco FlexLink

Overview

Reference

Flex Link Function

Check Point

FlexLink機能確認

通信影響確認

Summary

結果

再検証

Network Diagram

Environment

SW01 / SW02

SW03 / SW04

PC

Configuration

SW01

SW02

SW03 / SW04

MAC Address

Methods

Traffic off / Link down

SW01 : Link down

SW02 : mac address-table state

SW02 : mac address-table 保持時間

Traffic off / Link up

SW01 : Link up

SW02 : mac address-table state

SW02 : mac address-table 保持時間

Traffic on / Link down

SW01 : Link down

SW02 : mac address-table state

SW02 : mac address-table 保持時間

Ping

Traffic on / Link up

SW01 : Link Up

SW02 : mac address-table state

SW02 : mac address-table 保持時間

Ping

Dummy Multicast Packet

Source MAC Address

Protocol

Result

Dummy Multicast Packet

mac address-table に保持される時間

Consideration

mac address-table に保持される時間

mac address-table move update transmit/receive command

機能実装・利用