AS398999 BGP Communities

Advanced route control for traffic engineering, geographic distribution, and DDoS mitigation

What are BGP Communities?

BGP communities are tags you attach to your routes to control how we announce them globally. Control geographic distribution, prepending for traffic engineering, transit preferences, emergency mitigation, and more. All communities work across our entire 7-POP network.

🌍 Our Network Locations

Chicago (CHI) Toronto (TOR) Seattle (SEA) New York City (NYC) Ashburn (ASH) Frankfurt (FRA)

Geographic Control

Control which geographic regions announce your routes.

Community Description
398999:100:1 Announce in North America only (blocks Europe)
398999:100:2 Announce in Europe only (blocks North America)
398999:101:1 Do NOT announce in North America
398999:101:2 Do NOT announce in Europe

Geographic Prepending

Community Description
398999:102:1 Prepend 1x in North America
398999:102:2 Prepend 2x in North America
398999:102:3 Prepend 3x in North America
398999:103:1 Prepend 1x in Europe
398999:103:2 Prepend 2x in Europe
398999:103:3 Prepend 3x in Europe

💡 Example: Europe-Only Service

Running a service for European users? Only announce from Frankfurt:

set community 398999:100:2

Your prefix will only be announced from our Frankfurt location, keeping EU traffic in Europe.

POP-Specific Control

Announce at Single Location Only

Community Description
398999:150:100 Announce ONLY at Chicago
398999:150:101 Announce ONLY at Toronto
398999:150:200 Announce ONLY at Seattle
398999:150:400 Announce ONLY at NYC
398999:150:500 Announce ONLY at Ashburn
398999:150:300 Announce ONLY at Frankfurt
⚠️ Network Protection Policy:

If you limit announcements to specific POPs (using ANNOUNCE_ONLY or BLOCK communities) and receive a DDoS attack that exceeds those locations' mitigation capacity, we reserve the right to temporarily override your location restrictions and announce from additional POPs to distribute the attack load. This ensures network stability and protects our infrastructure. Once the attack subsides, your community preferences will be restored. For attacks exceeding 200Gbps, we strongly recommend announcing from all available locations.

Block Specific Location

Community Description
398999:151:100 Do NOT announce at Chicago
398999:151:101 Do NOT announce at Toronto
398999:151:200 Do NOT announce at Seattle
398999:151:400 Do NOT announce at NYC
398999:151:500 Do NOT announce at Ashburn
398999:151:300 Do NOT announce at Frankfurt
⚠️ Network Protection Policy:

If you limit announcements to specific POPs (using ANNOUNCE_ONLY or BLOCK communities) and receive a DDoS attack that exceeds those locations' mitigation capacity, we reserve the right to temporarily override your location restrictions and announce from additional POPs to distribute the attack load. This ensures network stability and protects our infrastructure. Once the attack subsides, your community preferences will be restored. For attacks exceeding 200Gbps, we strongly recommend announcing from all available locations.

POP-Specific Prepending

Format: 398999:16X:YYY where X is prepend count (0=1x, 1=2x, 2=3x) and YYY is POP ID.

Location 1x Prepend 2x Prepend 3x Prepend
Chicago 398999:160:100 398999:161:100 398999:162:100
Toronto 398999:160:101 398999:161:101 398999:162:101
Seattle 398999:160:200 398999:161:200 398999:162:200
NYC 398999:160:400 398999:161:400 398999:162:400
Ashburn 398999:160:500 398999:161:500 398999:162:500
Frankfurt 398999:160:300 398999:161:300 398999:162:300

💡 Example: Prefer NYC for Inbound Traffic

Want traffic to enter via NYC (100G port) with other locations as backup?

set community 398999:161:100 398999:161:200 398999:161:300

This prepends 2x at Chicago, Seattle, and Frankfurt, making NYC the most attractive path.

Traffic Engineering

Simple way to prefer a specific ingress point - we automatically prepend at all OTHER locations.

Community Description
398999:200:100 Prefer Chicago (2x prepend at all other POPs)
398999:200:101 Prefer Toronto (2x prepend at all other POPs)
398999:200:200 Prefer Seattle (2x prepend at all other POPs)
398999:200:400 Prefer NYC (2x prepend at all other POPs)
398999:200:500 Prefer Ashburn (2x prepend at all other POPs)
398999:200:300 Prefer Frankfurt (2x prepend at all other POPs)
💡 Tip:

The PREFER communities automatically apply 2x prepending everywhere EXCEPT your preferred location. Much simpler than manually setting prepend on each POP!

Upstream Transit Control

Block Specific Transit

Community Description
398999:250:174 Do NOT use Cogent (AS174)
398999:250:1299 Do NOT use Arelion/Telia (AS1299)
398999:250:6461 Do NOT use Zayo (AS6461)
398999:250:3257 Do NOT use GTT (AS3257)
398999:250:6939 Do NOT use Hurricane Electric (AS6939)
398999:250:2914 Do NOT use NTT (AS2914)
398999:250:3356 Do NOT use Lumen/Level3 (AS3356)

Prefer Specific Transit

Community Description
398999:260:1299 PREFER Arelion/Telia
398999:260:6461 PREFER Zayo
398999:260:2914 PREFER NTT
398999:260:6939 PREFER Hurricane Electric

💡 Example: Avoid Cogent (Peering Disputes)

set community 398999:250:174

Your prefix won't be announced via Cogent at any location. Traffic uses our other transit providers.

🚨 DDoS Mitigation & Emergency Controls

Blackholing

Drop all traffic to your prefix at specific locations during volumetric DDoS attacks.

Community Description
398999:400:666 Blackhole at ALL locations (emergency)
398999:401:100 Blackhole at Chicago only
398999:401:101 Blackhole at Toronto only
398999:401:200 Blackhole at Seattle only
398999:401:400 Blackhole at NYC only
398999:401:500 Blackhole at Ashburn only
398999:401:300 Blackhole at Frankfurt only
⚠️ Warning:

Blackholing drops ALL traffic to your prefix at the specified location(s). Only use during active attacks when you need to stop volumetric DDoS traffic.

⚠️ Network Protection Policy:

If you use blackholing or withdrawal communities and receive a DDoS attack that exceeds the remaining locations' mitigation capacity, we reserve the right to temporarily override your restrictions and announce from additional POPs to distribute the attack load. This ensures network stability and protects our infrastructure. Once the attack subsides, your community preferences will be restored. For attacks exceeding 200Gbps, we strongly recommend announcing from all available locations.

Withdraw from Specific POP

Completely withdraw announcement from a location (more aggressive than blackholing).

Community Description
398999:410:100 Withdraw from Chicago
398999:410:101 Withdraw from Toronto
398999:410:200 Withdraw from Seattle
398999:410:400 Withdraw from NYC
398999:410:500 Withdraw from Ashburn
398999:410:300 Withdraw from Frankfurt

Emergency Prepending

Extreme prepending (5x) to make a location highly unattractive during incidents.

Community Description
398999:420:100 Emergency 5x prepend at Chicago
398999:420:101 Emergency 5x prepend at Toronto
398999:420:200 Emergency 5x prepend at Seattle
398999:420:400 Emergency 5x prepend at NYC
398999:420:500 Emergency 5x prepend at Ashburn
398999:420:300 Emergency 5x prepend at Frankfurt

💡 Example: DDoS Attack from Europe

Under attack primarily from European sources? Emergency mitigation:

set community 398999:401:300 398999:420:300

Blackholes traffic at Frankfurt and adds 5x prepending. Attack stops while legitimate traffic from other regions continues.

Informational Communities (You Will See These)

These communities are automatically added by our network. You cannot set these - they're for information only.

Origin Location Tags

Shows which POP you're peering at / where your routes entered our network. This tag is preserved as your routes propagate globally.

Community Description
398999:10:100 Origin: Chicago
398999:10:101 Origin: Toronto
398999:10:200 Origin: Seattle
398999:10:400 Origin: NYC
398999:10:500 Origin: Ashburn
398999:10:300 Origin: Frankfurt

💡 Example: Origin Location Tag

You peer with us at Chicago and announce your prefix globally. When checking any looking glass worldwide, you'll see:

AS-PATH: ... 398999 YOUR_ASN
Communities: 398999:10:100

The 398999:10:100 tag shows your route originated at our Chicago location, even when it's being announced from all 6 of our POPs worldwide. To verify your routes are announced globally, check BGP looking glasses in different regions - you should see AS398999 in the path from multiple geographic locations, all carrying your Chicago origin tag.

How to Apply Communities

Cisco IOS / IOS-XE

router bgp 12345
 neighbor 10.x.x.x remote-as 398999
 address-family ipv4
  neighbor 10.x.x.x route-map TO-AS398999 out
!
route-map TO-AS398999 permit 10
 set community 398999:200:400 additive

Juniper JunOS

policy-options {
  policy-statement TO-AS398999 {
    term 1 {
      then {
        community add PREFER-NYC;
        accept;
      }
    }
  }
  community PREFER-NYC members 398999:200:400;
}

BIRD

filter TO_AS398999 {
  bgp_community.add((398999,200,400));
  accept;
}

FRRouting (FRR)

route-map TO-AS398999 permit 10
 set community 398999:200:400 additive
💡 Important:

Always use "additive" (Cisco/FRR) or "add" (Juniper/BIRD) mode to preserve existing communities. Multiple communities can be stacked.

Support & Resources

Need help with BGP communities or traffic engineering?