BGP Communities
Net Access uses BGP communities to control the announcement (or lack thereof) of routes to peers, and uses BGP communities to identify incoming routes. We hope this page will help you to better understand and implement them on your network.
| Transit | |||||
| Standard Community | Do Not Advertise | One Prepend | Two Prepends | Three Prepends | |
| All Transitors | 8001:1000 | 8001:10000 | 8001:10001 | 8001:10002 | 8001:10003 |
| UUNET | 8001:1001 | 8001:10010 | 8001:10011 | 8001:10012 | 8001:10013 |
| << Deprecated >> | 8001:1002 | 8001:10020 | 8001:10021 | 8001:10022 | 8001:10023 |
| SAVVIS | 8001:1003 | 8001:10030 | 8001:10031 | 8001:10032 | 8001:10033 |
| BBC | 8001:1004 | 8001:10040 | 8001:10041 | 8001:10042 | 8001:10043 |
| << Deprecated >> | 8001:1005 | 8001:10050 | 8001:10051 | 8001:10052 | 8001:10053 |
| << Deprecated >> | 8001:1006 | 8001:10060 | 8001:10061 | 8001:10062 | 8001:10063 |
| AT&T | 8001:1007 | 8001:10070 | 8001:10071 | 8001:10072 | 8001:10073 |
| WV Fiber, Inc. | 8001:1008 | 8001:10080 | 8001:10081 | 8001:10082 | 8001:10083 |
| Public Peering | |||||
| Standard Community | Do Not Advertise | One Prepend | Two Prepends | Three Prepends | |
| All Public Peers | 8001:2000 | 8001:20000 | 8001:20001 | 8001:20002 | 8001:20003 |
| NYIIX | 8001:2001 | 8001:20010 | 8001:20011 | 8001:20012 | 8001:20013 |
| << Deprecated >> | 8001:2002 | 8001:20020 | 8001:20021 | 8001:20022 | 8001:20023 |
| << Deprecated >> | 8001:2003 | 8001:20030 | 8001:20031 | 8001:20032 | 8001:20033 |
| LINX | 8001:2004 | 8001:20040 | 8001:20041 | 8001:20042 | 8001:20043 |
| << Deprecated >> | 8001:2005 | 8001:20050 | 8001:20051 | 8001:20052 | 8001:20053 |
| Equinix Ashburn | 8001:2006 | 8001:20060 | 8001:20061 | 8001:20062 | 8001:20063 |
| TorIX | 8001:2007 | 8001:20070 | 8001:20071 | 8001:20072 | 8001:20073 |
| Equinix Newark | 8001:2008 | 8001:20080 | 8001:20081 | 8001:20082 | 8001:20083 |
| NYCX | 8001:2009 | 8001:20090 | 8001:20091 | 8001:20092 | 8001:20093 |
| Private Peering | |||||
| Standard Community | Do Not Advertise | One Prepend | Two Prepends | Three Prepends | |
| All Private Peers | 8001:3000 | 8001:30000 | 8001:30001 | 8001:30002 | 8001:30003 |
| << Deprecated >> | 8001:3001 | 8001:30010 | 8001:30011 | 8001:30012 | 8001:30013 |
| Cogent | 8001:3002 | 8001:30020 | 8001:30021 | 8001:30022 | 8001:30023 |
| << Deprecated >> | 8001:3003 | 8001:30030 | 8001:30031 | 8001:30032 | 8001:30033 |
| font size="2">KDDI | 8001:3004 | 8001:30040 | 8001:30041 | 8001:30042 | 8001:3003 |
| RCN | 8001:3005 | 8001:30050 | 8001:30051 | 8001:30052 | 8001:30053 |
| Hurricane Electric | 8001:3006 | 8001:30060 | 8001:30061 | 8001:30062 | 8001:30063 |
| << Deprecated >> | 8001:3007 | 8001:30070 | 8001:30071 | 8001:30072 | 8001:30073 |
| Monmouth Internet | 8001:3008 | 8001:30080 | 8001:30081 | 8001:30082 | 8001:30083 |
| AboveNet | 8001:3009 | 8001:30090 | 8001:30091 | 8001:30092 | 8001:30093 |
| Cablevision/Lightpath | 8001:3010 | 8001:30100 | 8001:30101 | 8001:30102 | 8001:30103 |
| << Deprecated >> | 8001:3011 | 8001:30110 | 8001:30111 | 8001:30112 | 8001:30113 |
| << Deprecated >> | 8001:3012 | 8001:30120 | 8001:30121 | 8001:30122 | 8001:30123 |
| << Deprecated >> | 8001:3013 | 8001:30130 | 8001:30131 | 8001:30132 | 8001:30133 |
| << Deprecated >> | 8001:3014 | 8001:30140 | 8001:30141 | 8001:30142 | 8001:30143 |
| Global NAPs | 8001:3015 | 8001:30150 | 8001:30151 | 8001:30152 | 8001:30153 |
| Rogers Cable | 8001:3017 | 8001:30170 | 8001:30171 | 8001:30172 | 8001:30173 |
| Customer | ||||
| n/a | Standard Community | Decrease Local Preference | Standard Local Preference | Increase Local Preference |
| Customer | 8001:4000 | 8001:115 | 8001:120 | 8001:125 |
| NYC (Telehouse – 25 Broadway, NY, NY) | 8001:4001 | |||
| OCT (NAC – 1719 Route 10, Parsippany, NJ) | 8001:4002 | One Prepend | Two Prepends | Three Prepends |
| NWR (Equinix – 165 Halsey St, Newark, NJ) | 8001:4003 | |||
| ADC (MFN – 8100 Boone Blvd, McLean, VA) | 8001:4004 | 8001:1 | 8001:2 | 8001:3 |
| LTN (Telehouse Docklands – London, UK) | 8001:4005 | |||
| TLW (TelX – 60 Hudson St, New York, NY) | 8001:4006 | |||
| SNE (Sprint – 13 Adams St, Newton, NJ) | 8001:4007 | |||
| ASH (Equinix – Ashburn, VA) | 8001:4008 | |||
| CHI (Equinix – Chicago, IL) | 8001:4010 | |||
| NAC Originated | |
| Peer | Standard Community |
| NAC Originated | 8001:5000 |
| NYC (Telehouse – 25 Broadway, NY, NY) | 8001:5001 |
| OCT (NAC – 1719 Route 10, Parsippany, NJ) | 8001:5002 |
| NWR (Equinix – 165 Halsey St, Newark, NJ) | 8001:5003 |
| ADC (MFN, 8100 Boone Blvd, McLean, VA) | 8001:5004 |
| LTN (Telehouse Docklands, London, UK) | 8001:5005 |
| TLW (TelX – 60 Hudson St, New York, NY) | 8001:5006 |
| SNE (Sprint – 13 Adams St, Newton, NJ) | 8001:5007 |
| ASH (Equinix – Ashburn, VA) | 8001:5008 |
| TOR (RACO – Toronto, ON) | 8001:5009 |
| CHI (Equinix – Chicago, IL) | 8001:5010 |
8001:99 Route will NOT be prepended to any transit provider.
All routes within the NAC network also carry a local preference:
| 45 | De-Preferred Transit |
| 50 |
Standard Transit |
| 75 | De-Preferred Peering |
| 80 | Standard Peering |
| 80 | Preferred Transit |
| 90 | Preferred Peering |
| 115 | De-Preferred Customer or NAC Originated |
| 120 | Standard Customer or NAC Originated |
| 125 | Preferred Customer or NAC Originated |
Example route-maps
This example shows how to deny advertisement of all customer routes to UUNET
| route-map nac-out permit 10 set community 8001:10010 ! |
This example shows how to prepend advertisements to Genuity two times, and to Deny advertisements to UUNET
| route-map nac-out permit 10 set community 8001:10010 8001:10052 ! |
$Id: communities.html,v 1.26 2005-08-01 11:39:49-04 sjs Exp $
Applying BGP Community string with sample configuration
1. Get the latest BGP community string from your ISP/upstream provider or check www.ShowipBGP.com.
2. Pick the best BGP community string for your traffic shaping plan (mainly incoming traffic). Most of ISPs are providing BGP community string with local preference and AS prepending option. Cannot tell which one is better than the other. It will depend on your global traffic shaping plan.
3. Follow the below commands ( Cisco only )
The below Sample configuration will tag the 10.0.0.0/24 route with [ISP AS]:120 or [ISP AS]:3 and will not tag any other routes.
router#config t
router(config)#ip bgp-community new-format
router(config)#access-list 10 permit 10.0.0.0 0.0.0.255
router(config)#access-list 10 deny any
router(config)#route-map [to-ISP] permit 10
router(config-route-map)#match ip address 10
router(config-route-map)#set community [ISP AS]:120 <—- using Local Preference
or
router(config-route-map)#set community [ISP AS]:3 <——- using AS prepending
router(config-route-map)#route-map [to-ISP] permit 20
router(config-route-map)#exit
router(config)#router bgp [xxxx] <——————————- xxxx = customer’s ASN
router(config-router)#neighbor x.x.x.x send-community
router(config-router)#neighbor x.x.x.x route-map [to-ISP] out
router(config-router)#exit
router(config)#exit
router#copy running-config startup-config
4. And then, go to www.RouteServer.org and pick one of route server on the map to see your announcement. If you are using AS prepending option, you will see your AS prepends on route servers. Sometime you might not see your route with particular ISP path.
In most of case it might not be any routing problem, just the route path was dropped at somewhere by BGP best path selection scheme. Try Oregon route server, if you can see your route. The Oregon route server is providing many possible and available paths between BGP speakers and neighbors.
If you don’t see your route on there? check other route servers and also check your
BGP configuration. You might need to contact your upstream provider to check what they are learning BGP route from you.
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