Daftar Pertemuan
Pertemuan 1 Pertemuan 2 Pertemuan 3 Pertemuan 4 Pertemuan 5 Pertemuan 6 Pertemuan 7 Pertemuan 8 Pertemuan 9 Pertemuan 10 Pertemuan 11 Pertemuan 12 Pertemuan 13 Pertemuan 14 Pertemuan 15 Pertemuan 16
STP Tips
  • Root Bridge = Lowest Bridge ID
  • Bridge ID = Priority + MAC Address
  • PortFast untuk access ports
  • BPDUGuard proteksi dari loops
STP Port States
Blocking 20s
Listening 15s
Learning 15s
Forwarding -
Disabled -

Pertemuan 4: STP & RSTP Tuning

Bobot: 8%
Progress Pembelajaran 4/16
Tujuan Pembelajaran

Setelah menyelesaikan praktikum ini, mahasiswa mampu:

  • Memahami konsep Spanning Tree Protocol (STP) dan loop prevention
  • Memanipulasi root bridge election melalui priority adjustment
  • Mengkonfigurasi Rapid-PVST+ untuk faster convergence
  • Mengoptimalkan jaringan dengan PortFast, BPDUGuard, dan feature lainnya

Materi Teori - Spanning Tree Protocol

1. Konsep Dasar STP

Spanning Tree Protocol (STP) adalah protocol layer 2 yang mencegah bridging loops dalam jaringan Ethernet dengan redundant paths.

Problem: Broadcast Storms
  • Frame diduplikasi secara tak terbatas
  • MAC address table corruption
  • Network performance degradation
  • Complete network failure
Solution: STP
  • Membuat loop-free logical topology
  • Block redundant paths secara otomatis
  • Provide backup paths untuk redundancy
  • Maintain network stability
2. STP Operation dan Algorithm

STP bekerja melalui tiga langkah utama untuk membentuk loop-free topology:

Step 1: Root Bridge Election

Switch dengan lowest Bridge ID menjadi Root Bridge

Bridge ID = Priority + MAC
Lower Priority = Better
Same Priority = Lower MAC
Step 2: Root Port Selection

Setiap non-root bridge memilih port terdekat ke Root Bridge

1. Lowest Path Cost
2. Lowest Sender BID
3. Lowest Port ID
Step 3: Designated Port Selection

Satu designated port per segment untuk forwarding traffic

Per network segment:
- Root Bridge: All DP
- Others: One DP
3. STP Port States dan Timers

Setiap port dalam STP melewati beberapa state sebelum mencapai forwarding state:

Disabled
Admin Down
↓ Port Enabled
Blocking
20s
No forwarding, BPDUs only
↓ Max Age Timer
Listening
15s
Building active topology
↓ Forward Delay
Learning
15s
Learning MAC addresses
↓ Forward Delay
Forwarding
Active
Normal operation
STP Timers Default Values:
Timer Default Value Function
Hello Time 2 seconds BPDU transmission interval
Forward Delay 15 seconds Listening + Learning states
Max Age 20 seconds BPDU maximum storage time
Total Convergence Time:
Blocking → Listening: 20s (Max Age)
Listening → Learning: 15s (Forward Delay)
Learning → Forwarding: 15s (Forward Delay)
Total: 50 seconds

Root Port Change: 30-50 seconds
Direct Link Failure: 30 seconds
Indirect Link Failure: 50 seconds
4. STP Variants dan Evolusi

Beberapa versi STP yang dikembangkan untuk meningkatkan performance dan features:

Protocol Convergence VLAN Support Standard Key Features Recommendation
STP 30-50 seconds Single Instance 802.1D Original standard Not recommended
PVST+ 30-50 seconds Per-VLAN Cisco VLAN load balancing Legacy
RSTP 1-2 seconds Single Instance 802.1w Rapid convergence Small networks
Rapid-PVST+ 1-2 seconds Per-VLAN Cisco Fast + VLAN awareness Recommended
MSTP 1-2 seconds Multiple Instances 802.1s Scalable for large networks Enterprise
5. STP Optimization Features

Berbagai feature untuk mengoptimalkan STP operation dan security:

PortFast

Immediately transitions access ports to forwarding state

interface fa0/1
spanning-tree portfast
BPDUGuard

Disables port if BPDU received on PortFast port

interface fa0/1
spanning-tree bpduguard enable
BPDUFilter

Prevents BPDU transmission on specified ports

interface fa0/1
spanning-tree bpdufilter enable
UplinkFast

Fast convergence when primary uplink fails

spanning-tree uplinkfast
BackboneFast

Reduces convergence time for indirect link failures

spanning-tree backbonefast

Job Sheet Praktikum

Informasi Job Sheet
Durasi: 170 menit
Tujuan

Optimasi jaringan dengan STP & RSTP

Tools

Cisco Packet Tracer

Bobot

8%

Penilaian

Laporan Praktikum

Diagram Topologi STP dengan Redundant Links
Switch A
Root Bridge
Priority: 4096
Fa0/1
Fa0/2
Fa0/3
Fa0/4
Root
Switch B
Secondary Root
Priority: 8192
Fa0/1
Fa0/2
Fa0/3
Fa0/4
Designated
Switch C
Non-Root Bridge
Priority: 32768
Fa0/1
Fa0/2
Fa0/3
Fa0/4
Non-Root
Switch A
PC1
PC2
Switch B
PC3
PC4
Switch C
PC5
PC6
Keterangan Topologi:
  • 3 Switch Cisco 2960 dengan redundant links
  • Switch A: Root Bridge (Priority 4096)
  • Switch B: Secondary Root (Priority 8192)
  • Switch C: Non-Root (Priority 32768)
  • Port Roles: Root (R), Designated (D), Alternate (A)
  • Redundant Links: Multiple paths create potential loops
  • STP Optimization: PortFast, BPDUGuard pada access ports
STP Configuration Plan
Switch Priority Expected Role Root Port Designated Ports Blocked Ports
Switch A 4096 Root Bridge - All Ports -
Switch B 8192 Designated Bridge Fa0/1 Fa0/2, Fa0/4 Fa0/3
Switch C 32768 Non-Root Bridge Fa0/1 Fa0/3, Fa0/4 Fa0/2
Port Connections Plan
Connection Ports Link Type Expected STP State
Switch A ↔ Switch B Fa0/1 - Fa0/1 Trunk Forwarding (Both)
Switch A ↔ Switch C Fa0/2 - Fa0/1 Trunk Forwarding (Both)
Switch B ↔ Switch C Fa0/2 - Fa0/2 Trunk Forwarding (B) / Blocking (C)
PC Connections All Fa0/3-4 Access Forwarding (With PortFast)
Langkah Kerja Detail
Langkah 1: Persiapan Topologi dan Basic Connectivity 20 menit

Buat topologi loop dengan redundant links dan konfigurasi trunking:

Physical Connections:
  • SwitchA Fa0/1 ↔ SwitchB Fa0/1
  • SwitchA Fa0/2 ↔ SwitchC Fa0/1
  • SwitchB Fa0/2 ↔ SwitchC Fa0/2
  • PC1-2 → SwitchA Fa0/3-4
  • PC3-4 → SwitchB Fa0/3-4
  • PC5-6 → SwitchC Fa0/3-4
Trunk Configuration:
! Pada semua switch untuk inter-switch links
configure terminal
interface range fastethernet 0/1-2
  switchport mode trunk
  switchport trunk native vlan 99
  no shutdown
exit
Pastikan:
  • Semua trunk ports dalam mode trunk
  • Native VLAN konsisten (VLAN 99)
  • STP aktif secara default (mencegah loops)
Langkah 2: Analisis STP Default Behavior 25 menit

Analisis bagaimana STP bekerja secara default tanpa konfigurasi manual:

STP Status Check:
! Cek status STP default
show spanning-tree
show spanning-tree summary
show spanning-tree root

! Identifikasi root bridge default
show spanning-tree vlan 1
show spanning-tree bridge
Expected Observations:
  • Satu switch menjadi Root Bridge (lowest MAC)
  • Satu port blocked per loop (Alternate role)
  • Root Ports selected berdasarkan path cost
  • Designated Ports pada setiap segment
Document Default Root Bridge:
Switch# show spanning-tree root

Root   Hello Max Fwd
Vlan        Root ID   Cost Time Age Dly Root Port

VLAN0001 32769 0011.bb0b.3600  19   2  20 15 Fa0/1
Langkah 3: Manipulasi Root Bridge Election 35 menit

Manipulasi STP untuk memilih root bridge sesuai design plan:

Switch A sebagai Primary Root:
! Di Switch A
configure terminal

! Method 1: Primary root command
spanning-tree vlan 1 root primary

! Method 2: Manual priority
spanning-tree vlan 1 priority 4096

! Verifikasi
show spanning-tree vlan 1
show spanning-tree root
Switch B sebagai Secondary Root:
! Di Switch B
configure terminal

! Method 1: Secondary root command
spanning-tree vlan 1 root secondary

! Method 2: Manual priority
spanning-tree vlan 1 priority 8192

! Switch C biarkan default
show spanning-tree vlan 1
! Priority tetap 32768
Priority Values:
  • 0-61440: Configurable values (increments of 4096)
  • 32768: Default priority
  • 4096: Typical root bridge priority
  • 8192: Typical secondary root priority
Langkah 4: Konfigurasi Rapid-PVST+ (RSTP) 25 menit

Upgrade dari STP ke Rapid-PVST+ untuk faster convergence:

! Pada semua switch
configure terminal

! Aktifkan Rapid-PVST+
spanning-tree mode rapid-pvst

! Verifikasi RSTP convergence
show spanning-tree
show spanning-tree interface fa0/1 detail
show spanning-tree summary

! Perhatikan perbedaan state
show spanning-tree vlan 1
! Look for "RSTP" in output
RSTP Port States vs STP:
STP State RSTP State Convergence Time
Blocking, Listening Discarding Immediate
Learning Learning Forward Delay
Forwarding Forwarding Immediate
Langkah 5: Optimasi dengan PortFast dan BPDUGuard 30 menit

Konfigurasi optimasi untuk access ports dengan PortFast dan BPDUGuard:

PortFast Configuration:
! Pada semua switch untuk access ports
configure terminal
interface range fastethernet 0/3-4
  spanning-tree portfast
  ! Port immediately goes to forwarding
exit

! Global PortFast (optional)
spanning-tree portfast default
BPDUGuard Configuration:
! Aktifkan BPDUGuard pada PortFast ports
interface range fastethernet 0/3-4
  spanning-tree bpduguard enable
  ! Port shuts down if BPDU received
exit

! Global BPDUGuard (alternative)
spanning-tree portfast bpduguard default
BPDUFilter (Optional):
interface range fastethernet 0/3-4
  spanning-tree bpdufilter enable
  ! Prevents BPDU transmission
exit
Verification:
show spanning-tree interface fa0/3 detail
show spanning-tree summary
show interfaces status | include err-disabled
Langkah 6: Advanced STP Features 20 menit

Konfigurasi advanced features untuk optimasi tambahan:

UplinkFast dan BackboneFast:
! UplinkFast pada Switch B dan C
spanning-tree uplinkfast
  ! Fast convergence for uplink failure

! BackboneFast pada semua switch
spanning-tree backbonefast
  ! Reduces convergence for indirect failures
Path Cost dan Port Priority:
! Manipulasi path selection dengan cost
interface fastethernet 0/1
  spanning-tree cost 1700000
  ! Make path less preferred
exit

! Manipulasi port priority
interface fastethernet 0/2
  spanning-tree port-priority 0
exit
Langkah 7: Testing dan Verification 15 menit

Lakukan comprehensive testing untuk memverifikasi STP operation:

STP Verification:
! Verifikasi root bridge election
show spanning-tree root
show spanning-tree vlan 1

! Test convergence time
! Putus link antara Switch A dan Switch B
! Ukur waktu convergence dengan ping
ping 192.168.1.10 -t
! Ganti dengan IP PC yang sesuai
BPDUGuard Testing:
! Test BPDUGuard protection
! Coba hubungkan switch lain ke port dengan BPDUGuard
! Amati port status (harus error-disable)

! Recovery dari error-disable
interface fa0/3
  shutdown
  no shutdown
exit
Convergence Time Measurement:
Scenario STP Convergence RSTP Convergence
Direct Link Failure 30 seconds 1-2 seconds
Indirect Link Failure 50 seconds 1-2 seconds
Root Bridge Change 50 seconds 1-2 seconds

Kriteria Penilaian

Kriteria Indikator Bobot Status
Root Bridge Manipulation Root bridge berhasil dimanipulasi sesuai plan dengan priority yang tepat 2.5% Check
RSTP Implementation Rapid-PVST+ berhasil diimplementasikan dan diverifikasi 2.0% Check
PortFast & BPDUGuard PortFast dan BPDUGuard terkofigurasi dengan benar pada access ports 1.5% Check
Convergence Analysis Convergence time terukur dan dianalisis (STP vs RSTP comparison) 1.0% Check
Advanced Features UplinkFast, BackboneFast, dan path cost manipulation berfungsi 0.5% Check
Troubleshooting Mampu identifikasi dan selesaikan STP-related issues 0.5% Check
Total 8% Complete

Tips dan Best Practices STP

Security Best Practices
  • Selalu gunakan BPDUGuard pada PortFast ports untuk mencegah STP manipulation attacks
  • Implementasi Root Guard pada ports yang tidak seharusnya menjadi root bridge
  • Gunakan Loop Guard untuk mencegah alternate ports menjadi designated karena BPDU loss
  • Monitor untuk BPDU rate limiting attacks
Configuration Tips
  • Selalu manually configure root bridge priorities daripada mengandalkan MAC address
  • Gunakan Rapid-PVST+ daripada legacy STP untuk faster convergence
  • Implementasi PortFast hanya pada access ports yang terhubung ke end devices
  • Documentasikan STP topology dan expected port roles
Common STP Issues and Solutions:
  • Network loops: Verifikasi STP operation dan port states
  • Slow convergence: Upgrade ke RSTP atau optimasi timer
  • Unstable root bridge: Configure manual root bridge priorities
  • BPDU filtering issues: Pastikan BPDUFilter tidak menyebabkan loops
Pertemuan 3 Pertemuan 5: OSPF Single-Area