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AWS Hybrid Route Table Resolver Sandbox

TGW & DXGW Engine LPM Simulator

Ketika paket data bergerak di dalam ekosistem AWS, keputusan forwarding dievaluasi berdasarkan aturan Longest Prefix Match (LPM) di berbagai layer route table: dari VPC Subnet Route Table, Transit Gateway Route Table, hingga Direct Connect Gateway dan BGP Route Table.

AWS Hybrid Routing & Direct Connect Failover Sandbox
TGW & DXGW EngineLPM Resolver

Uji skenario routing multi-VPC, resolusi Longest Prefix Match (LPM) Radix Tree, serta simulasi failover seketika ketika link Direct Connect mengalami degradasi/down ke VPN backup.

Primary Circuit
Direct Connect Transit VIF
Backup Circuit
IPSec Site-to-Site VPN
TGW Inspection Feature
Appliance Mode
LPM Radix Trie Match Inspector for 192.168.100.50 Winner: 192.168.100.0/24 (/24)
10.10.0.0/16VPC
local (Nitro VPC Delivery)
✖ No Match
10.0.0.0/8VPC
tgw-attach-01
✖ No Match
192.168.0.0/16VPC
tgw-attach-01
✔ Encompassing (/ 16 bits)
0.0.0.0/0VPC
nat-0123456789abcdef
✔ Encompassing (/ 0 bits)
10.10.0.0/16TGW
vpc-spoke-1
✖ No Match
10.20.0.0/16TGW
vpc-spoke-2
✖ No Match
10.99.0.0/16TGW
vpc-inspection (GWLB)
✖ No Match
192.168.100.0/24TGW
dxgw-transit-vif (AS 64512)
★ Longest Match (/ 24 bits)
192.168.100.0/24TGW
vpn-backup-tunnel (AS 64512)
★ Longest Match (/ 24 bits)
VPC Spoke Route Table (rtb-0123)Local VPC
Destination PrefixTargetStatus
10.10.0.0/16local (Nitro VPC Delivery)Active (Immutable)
10.0.0.0/8tgw-attach-01Active
192.168.0.0/16tgw-attach-01Active
0.0.0.0/0nat-0123456789abcdefActive
TGW Core Route Table (tgw-rtb-0abc)TGW Fabric
Destination PrefixNext HopBGP Status
10.10.0.0/16vpc-spoke-1Propagated
10.20.0.0/16vpc-spoke-2Propagated
10.99.0.0/16vpc-inspection (GWLB)Propagated
192.168.100.0/24dxgw-transit-vif (AS 64512)Active (BGP Best Path)
192.168.100.0/24vpn-backup-tunnel (AS 64512)Standby (AS-Prepended / Lower Local-Pref)
AWS Route Engine Trace & Forwarding Decision
[VPC Subnet Lookup] Mengevaluasi paket dari 10.10.1.25 ke 192.168.100.50
[LPM Match: /16] Matched '192.168.0.0/16' -> Target: tgw-attach-01 (Forwarding to AWS Transit Gateway)
[TGW Route Table Lookup] Memeriksa TGW Spoke Association Table (LPM /24)...
[TGW Forwarding] TGW Best Path: dxgw-transit-vif (Direct Connect Dedicated Circuit)
[Transport Layer] 802.1Q Encapsulation + AWS Private Backbone ➔ On-Prem Router
FORWARDING SUCCESS: Packet berhasil diteruskan ke destination target melalui active path.

Hirarki & Prioritas Route Table di AWS VPC

Jika terdapat beberapa route entry yang cocok dengan IP tujuan di dalam sebuah VPC Route Table, AWS menerapkan hirarki prioritas berikut:

Aturan Emas Routing AWS:

  1. Local Route bersifat Immutable: Route lokal untuk primary dan secondary CIDR VPC dibuat otomatis oleh AWS dan tidak dapat dihapus atau di-override oleh prefix yang lebih spesifik.
  2. Longest Prefix Match (LPM): Prefix yang lebih spesifik (misal /28 atau /24) selalu mengalahkan prefix yang lebih luas (misal /16 atau /0).
  3. Static Route over Propagated Route: Jika terdapat prefix berukuran sama (misal sama-sama 10.50.0.0/16), static route yang dikonfigurasi manual akan selalu mengalahkan propagated route dari Virtual Private Gateway (VGW).

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