JUNOS_RSTP(VSTP)
JUNOSのRSTP・・・厳密にはVSTPメモ
実際には、CiscoオンリーのNWはあったとしても、JuniperオンリーのNW構成は相当少ないだろうから、Ciscoも入れた下記構成で確認
まずは、3750のConfig
!
spanning-tree mode rapid-pvst
!
!
interface GigabitEthernet1/0/1
switchport trunk encapsulation dot1q
switchport mode trunk
!
interface GigabitEthernet1/0/2
switchport trunk encapsulation dot1q
switchport mode trunk
!
次はJUNOS側
SW1/SW2のconfig
set interfaces ge-0/0/2 unit 0 family ethernet-switching port-mode trunk
set interfaces ge-0/0/2 unit 0 family ethernet-switching vlan members v100
set interfaces ge-0/0/2 unit 0 family ethernet-switching vlan members v200set interfaces ae0 unit 0 family ethernet-switching port-mode trunk
set interfaces ae0 unit 0 family ethernet-switching vlan members v100
set interfaces ae0 unit 0 family ethernet-switching vlan members v200set protocols vstp vlan v100
set protocols vstp vlan v200
この状態で、Cisco側のshowの結果(面倒なのでVLAN100のみ)
#show span vlan 100
VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 32868
Address 0026.cb1b.AAAA
This bridge is the root
Hello Time 2 sec Max Age 20 sec Forward Delay 15 secBridge ID Priority 32868 (priority 32768 sys-id-ext 100)
Address 0026.cb1b.AAAA
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 secInterface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 4 128.1 P2p
Gi1/0/2 Desg FWD 4 128.2 P2p
CiscoがRootブリッジになってるので、JUNOS側で確認
# run show spanning-tree interface
Spanning tree interface parameters for VLAN 100
Interface Port ID Designated Designated Port State Role
port ID bridge ID Cost
ae0.0 128:1 128:1 32868.7819f791BBBB 10000 BLK ALT
ge-0/0/2.0 128:515 128:1 32868.0026cb1bAAAA 20000 FWD ROOT
Cost値に注目
ge-0/0/2のパスコストがCiscoの値(4)と異なっている のは、デフォルトでCiscoのパスコストが16bitで、JUNOSは32bitであるから。
試しにCisco側で32bitに変更してみる。
投入Config
(config)#spanning-tree pathcost method long
投入後
#show spanning-tree vlan 100
(略)
Interface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Desg FWD 20000 128.1 P2p
Gi1/0/2 Desg FWD 20000 128.2 P2p
→JUNOSのge-0/0/2のパスコストと同じ値になった。
今度は、Root bridgeをCiscoからJUNOS(SW1)に変更してみる。
SW1側で以下を投入
# set protocols vstp vlan all bridge-priority 4k
これで、SW1がVLAN100、VLAN200Rootになると予想
commit&確認
# run show chassis mac-addresses
FPC 0 MAC address information:
Public base address 78:fe:3d:44:CC:CC
Public count 128
# run show spanning-tree bridge
STP bridge parameters
Context ID : 1
Enabled protocol : RSTPSTP bridge parameters for VLAN 100
Root ID : 32868.00:26:cb:1b:AA:AA
Root cost : 20000
Root port : ge-0/0/2.0
Hello time : 2 seconds
Maximum age : 20 seconds
Forward delay : 15 seconds
Message age : 1
Number of topology changes : 9
Time since last topology change : 1267 seconds
Topology change initiator : ge-0/0/2.0
Local parameters
Bridge ID : 32868.78:fe:3d:44:CC:CC
Extended system ID : 1
Internal instance ID : 0
想定と異なり、Root IDがCisco側にRoot Guardはないにも関わらずCiscoのまま。
設定投入の仕方を変える。
# delete protocols vstp vlan all
# set protocols vstp vlan v100 bridge-priority 4k
SW1側で確認
# run show spanning-tree bridge
STP bridge parameters
Context ID : 1
Enabled protocol : RSTPSTP bridge parameters for VLAN 100
Root ID : 4196.78:fe:3d:44:CC:CC
Hello time : 2 seconds
Maximum age : 20 seconds
Forward delay : 15 seconds
Message age : 0
Number of topology changes : 10
Time since last topology change : 51 seconds
Topology change initiator : ae0.0
Local parameters
Bridge ID : 4196.78:fe:3d:44:CC:CC
Extended system ID : 1
Internal instance ID : 0
念のためCiscoでも確認
#show spanning-tree
VLAN0100
Spanning tree enabled protocol rstp
Root ID Priority 4196
Address 78fe.3d44.CCCC
Cost 20000
Port 1 (GigabitEthernet1/0/1)
Hello Time 2 sec Max Age 20 sec Forward Delay 15 secBridge ID Priority 32868 (priority 32768 sys-id-ext 100)
Address 0026.cb1b.AAAA
Hello Time 2 sec Max Age 20 sec Forward Delay 15 sec
Aging Time 300 secInterface Role Sts Cost Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi1/0/1 Root FWD 20000 128.1 P2p
Gi1/0/2 Altn BLK 20000 128.2 P2p
パスコストは忘れがちなので、Cisco--Juniperの混在環境では気を付けないと