Routing Policy and Preferences

Introduction

IEDON-NET (AS4242422189) implements an intelligent BGP routing policy designed to optimize traffic flow through geographical awareness, link quality assessment, and comprehensive route validation. This document describes our routing implementation and peering policies.

Route Validation

• ROA Validation: We only accept ROA_VALID and ROA_UNKNOWN routes, filtering out all ROA_INVALID routes
• ROA Updates: ROA data is refreshed every 30 minutes to ensure up-to-date validation
• Session Types: By default, all peering sessions are treated as Full Table sessions, meaning we export and import all valid routes unless otherwise specified

Network Security

We restrict WireGuard tunnel traffic to the following IP address ranges:

• fe80::/10 (IPv6 Link-Local)
• fd00::/8 (IPv6 Unique Local Addresses)
• 172.16.0.0/12 (Private IPv4 space)
• 10.0.0.0/8 (Private IPv4 space)

BGP Local Preference (local_pref)

Local preference determines route preference within IEDON-NET and implements our cold potato routing strategy to keep traffic within the same geographical region when possible.

Local Preference Values

Geographical Routing Logic

Our implementation prioritizes geographical proximity using DN42 community standards:

1. Region Priority: Routes are evaluated based on DN42 region communities (64511, 41-70)
2. Country Fallback: When region information is unavailable, country communities (64511, 1000-1999) are used
3. Cold Potato Strategy: Traffic is routed via IGP to the nearest region or country, keeping it within our network longer

Route Preference Decision Matrix

BGP Multi-Exit Discriminator (MED)

The MED attribute implements a comprehensive cost metric that considers link quality, latency, bandwidth, and encryption level. We update link latency values every hour based on average RTT with penalties for packet loss.

MED Calculation

For iBGP Routes (Internal)

bgp_med = 200000 + igp_cost

• Base value: 200000 (identifies internal routes)
• IGP cost: Accumulated internal network cost

For eBGP Routes (External)

bgp_med = 100000 + crypto_penalty + bandwidth_penalty + latency_penalty

Where:

• Base value: 100000 (identifies external routes)
• Crypto penalty: (40000 - (dn42_crypto_level - 30) * 10000)
• Bandwidth penalty: (9000 - (dn42_bandwidth_level - 20) * 1000)
• Latency penalty: dn42_latency_level(calculated by effective RTT described in section "Link Quality Assessment") * 100

⚠ Warning

DO NOT ADD/TAG COUNTRY AND REGION COMMUNITIES ON ROUTES THAT NOT BELONG TO YOU

Here is how to correctly set DN42 region community flag, copied from DN42 Wiki:

• Unlike the other community values, the DN42_REGION community should only be set on routes originating from your network! (This is what the source = RTS_STATIC check does).
• Otherwise, if you export routes across multiple regions within your network, you may be sending incorrect origin information to other peers.

Beyond that, you may also be breaking region optimization for route decision.

Link Quality Assessment

We use DN42 standard communities to assess and control traffic routing based on link characteristics:

Latency Communities (64511, 1-9)

However, to calculate final latency level, we will apply another loss penalty to the raw average latency used:

effective_RTT = average_RTT * (1 + loss_rate * penalty_factor), where penalty_factor is 2.0 .

Bandwidth Communities (64511, 21-29)

Encryption Communities (64511, 31-34)

Peer Relationship Policies

IEDON-NET implements RFC 9234-style routing policies based on peer relationship roles to control route import/export behavior.

Available Peer Roles

Route Import Policies

• From PEER/DOWNSTREAM: Only accept their own networks
• From TRANSIT/UPSTREAM: Accept all valid routes (they provide full transit)
• From FULL: Accept all valid routes (no filtering restrictions)

Route Export Policies

• To TRANSIT/PEER: Only export own routes and customer routes
• To UPSTREAM: Only export own routes and customer routes
• To DOWNSTREAM: Export all valid routes (provide full transit)
• To FULL: Export all valid routes (no filtering restrictions)

BGP Communities Reference

Well-Known Communities

• (65535, 666) - Blackhole community (RFC 7999) - Route will be blackholed
• (65535, 65281) - NO_EXPORT - Do not advertise outside AS
• (65535, 65282) - NO_ADVERTISE - Do not advertise to any peer

DN42 Standard Communities

See the DN42 Wiki: BGP Communities for complete details.

• (64511, link_latency) - Link latency classification (1-9)
• (64511, link_bandwidth) - Link bandwidth classification (21-29)
• (64511, link_crypto) - Link encryption level (31-34)
• (64511, region_code) - DN42 region code (41-70)
• (64511, country_code) - DN42 country code (1000-1999)

IEDON-NET Specific Large Communities

• (4242422189, 255, P) - IEDON-NET IGP cost (where P = IGP cost, 0 if route doesn't traverse our IGP)
• (4242422189, 100, Q) - IEDON-NET Node ID (where Q = IGP Node ID from which route was learned)
• (4242422189, 101, R) - IEDON-NET Node Region (where R = IGP Node Region from which route was learned)
• (4242422189, 102, S) - IEDON-NET Node Country (where S = IGP Node Country from which route was learned)
• (4242422189, 10, T) - Peer relationship role (where T = role value 0-4)

Internal Tracking Communities

• (64496, region) - Previous hop region tracking
• (64497, country) - Previous hop country tracking
• (64498, cost) - Internal network cost accumulation

This routing policy ensures optimal performance while maintaining security and providing predictable traffic engineering capabilities for IEDON-NET and our peers.