Cisco : Spanning Tree Protocol

Cisco : Spanning Tree Protocol

Dalam dunia jaringan komputer, Spanning Tree Protocol (STP) adalah teknologi dasar yang mencegah bencana yang ditakuti oleh semua administrator jaringan—loop jaringan. Loop terjadi ketika terdapat jalur redundan dalam jaringan, yang meskipun bermanfaat untuk toleransi kesalahan, dapat menyebabkan broadcast storm dan ketidakstabilan jaringan jika tidak dikelola dengan baik.

STP adalah protokol Layer 2 yang didefinisikan oleh IEEE 802.1D yang memastikan topologi bebas loop dalam jaringan dengan mengelola jalur redundan antara switch jaringan secara cerdas. Protokol ini bekerja dengan secara selektif memblokir dan meneruskan lalu lintas pada jalur yang berbeda, memastikan hanya satu jalur aktif yang digunakan untuk mengirim data, sementara jalur redundan lainnya ditempatkan dalam status cadangan.

Tujuan utama dari STP adalah untuk:

Mencegah loop jaringan dengan memblokir jalur redundan.
Memberikan redundansi dengan mengaktifkan jalur cadangan jika jalur utama gagal.
Memastikan aliran data yang efisien dalam jaringan yang sangat tersedia dan bebas loop.

Syntax

Berikut adalah syntax command yang digunakan dalam konfigurasi Spanning Tree Protocol (STP).

Basic Commands

Command	Description
`spanning-tree mode [mode]`	Mengubah mode protocol Spanning Tree. Contoh: `pvst`, `rapid-pvst`, `mst`
`spanning-tree vlan [vlan_id] priority [value]`	Mengatur nilai bridge priority (semakin kecil nilai, semakin tinggi prioritas)
`spanning-tree vlan [vlan_id] root primary`	Menetapkan switch sebagai Root Bridge, gunakan `secondary` sebagai backup

Show Commands

Command	Description
`show spanning-tree`	Memeriksa status Spanning Tree
`show spanning-tree vlan [vlan_id]`	Memeriksa status STP pada VLAN tertentu
`show spanning-tree interface [interface_id]`	Memperiksa konfigurasi STP untuk unterface Tertentu

Topologi

Pada topology jaringan ini sama sekali belum dikonfigurasi untuk spanning tree

Mappinglah port spannnig three dalam topology ini dan carilah root switch
- Root Port [R]
- Designated Port [D]
- Alternate Port [A]

Proses Pencarian

SW1

SW1#show spanning-tree 
VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     5010.df00.4500
             Cost        4
             Port        3 (GigabitEthernet0/2)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     5029.fd00.4400
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Desg FWD 4         128.1    P2p 
Gi0/1               Desg FWD 4         128.2    P2p 
Gi0/2               Root FWD 4         128.3    P2p 
Gi0/3               Desg FWD 4         128.4    P2p

SW2

SW2#show spanning-tree 
VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     5010.df00.4500
             Cost        4
             Port        3 (GigabitEthernet0/2)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     50fc.1600.4700
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Altn BLK 4         128.1    P2p 
Gi0/1               Desg FWD 4         128.2    P2p 
Gi0/2               Root FWD 4         128.3    P2p 
Gi0/3               Desg FWD 4         128.4    P2p

SW3

SW3#show spanning-tree 
VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     5010.df00.4500
             Cost        8
             Port        1 (GigabitEthernet0/0)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     50b9.d400.4600
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Root FWD 4         128.1    P2p 
Gi0/1               Altn BLK 4         128.2    P2p

SW4

SW4#show spanning-tree 

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     5010.df00.4500
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     5010.df00.4500
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Desg FWD 4         128.1    P2p 
Gi0/1               Desg FWD 4         128.2    P2p

SW5

SW5#show spanning-tree 

VLAN0001
  Spanning tree enabled protocol ieee
  Root ID    Priority    32769
             Address     5010.df00.4500
             Cost        8
             Port        1 (GigabitEthernet0/0)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     5040.b700.4800
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Root FWD 4         128.1    P2p 
Gi0/1               Altn BLK 4         128.2    P2p

Untuk mendapatkan jalur switching yang efisien SW4 bukan root birdge yang benar. Maka perlu untuk dikonfigurasi sebagai berikut

Konfigurasi SW1 Menjadi Root Switch
Konfigurasi SW2 Menjadi Backup root
Aktifkan RSTP
Setelahnya, untuk memastikan lakukan mapping port lagi.

Konfigurasi

SW1

SW1(config)#spanning-tree vlan 1 root primary 
SW1(config)#spanning-tree mode rapid-pvst

SW2

SW2(config)#spanning-tree vlan 1 root secondary 
SW2(config)#spanning-tree mode rapid-pvst

SW3

SW3(config)#spanning-tree mode rapid-pvst

SW4

SW4(config)#spanning-tree mode rapid-pvst

SW5

SW5(config)#spanning-tree mode rapid-pvst

Testing

Hasil Configurasi

SW1

SW1#show spanning-tree
VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    24577
             Address     5029.fd00.4400
             This bridge is the root
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    24577  (priority 24576 sys-id-ext 1)
             Address     5029.fd00.4400
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Desg FWD 4         128.1    P2p
Gi0/1               Desg FWD 4         128.2    P2p
Gi0/2               Desg FWD 4         128.3    P2p
Gi0/3               Desg FWD 4         128.4    P2p

SW2

SW2#show spanning-tree
VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    24577
             Address     5029.fd00.4400
             Cost        4
             Port        1 (GigabitEthernet0/0)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    28673  (priority 28672 sys-id-ext 1)
             Address     50fc.1600.4700
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  15  sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Root FWD 4         128.1    P2p
Gi0/1               Desg FWD 4         128.2    P2p
Gi0/2               Desg FWD 4         128.3    P2p
Gi0/3               Desg FWD 4         128.4    P2p

SW3

SW3#show spanning-tree
VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    24577
             Address     5029.fd00.4400
             Cost        4
             Port        1 (GigabitEthernet0/0)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     50b9.d400.4600
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Root FWD 4         128.1    P2p
Gi0/1               Altn BLK 4         128.2    P2p

SW4

SW4#show spanning-tree
VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    24577
             Address     5029.fd00.4400
             Cost        4
             Port        2 (GigabitEthernet0/1)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     5010.df00.4500
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Altn BLK 4         128.1    P2p
Gi0/1               Root FWD 4         128.2    P2p

SW5

SW5#show spanning-tree
VLAN0001
  Spanning tree enabled protocol rstp
  Root ID    Priority    24577
             Address     5029.fd00.4400
             Cost        4
             Port        1 (GigabitEthernet0/0)
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec

  Bridge ID  Priority    32769  (priority 32768 sys-id-ext 1)
             Address     5040.b700.4800
             Hello Time   2 sec  Max Age 20 sec  Forward Delay 15 sec
             Aging Time  300 sec

Interface           Role Sts Cost      Prio.Nbr Type
------------------- ---- --- --------- -------- --------------------------------
Gi0/0               Root FWD 4         128.1    P2p
Gi0/1               Altn BLK 4         128.2    P2p

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