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BGP Community Attributes List

BGP Community String for Alta Tecnologia AS16030

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	Standard Community	Do Not Advertise	One Prepend	Two Prepends	Three Prepends
All	16030:100	16030:1000	16030:1001	16030:1002	16030:1003
All Transits	16030:101	16030:1010	16030:1011	16030:1012	16030:1013
All Peers	16030:102	16030:1020	16030:1021	16030:1022	16030:1023
All Customers	16030:103	16030:1030	16030:1031	16030:1032	16030:1033
Catnix (Barcelona)	16030:104	16030:1040	16030:1041	16030:1042	16030:1043
SwissIX (Zurich)	16030:105	16030:1050	16030:1051	16030:1052	16030:1053
NYIIX (New York)	16030:106	16030:1060	16030:1061	16030:1062	16030:1063
Ams-IX (Amsterdam)	16030:107	16030:1070	16030:1071	16030:1072	16030:1073
Linx (London)	16030:108	16030:1080	16030:1081<	16030:1082	16030:1083

Route maps examples:

This example shows how to deny all your advertisement to All Transits:

route-map altecom-out
permit 10
set community 16030:1010

This example shows how to prepend advertisements to Ams-IX two times, and deny advertisements to All Transits:

route-map altecom-out
permit 10
set community 16030:1010 16030:1072

Applying BGP Community string with sample configuration

1. Get the latest BGP community string from your ISP/upstream provider or check new.CiscoNET.com web site.

2. Pick the best BGP community string for your traffic shaping plan (mainly incoming traffic). Most of ISPs are providing 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 16030:1032 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-AS16030 permit 10
router(config-route-map)#match ip address 10

router(config-route-map)#set community 16030:1032 <------ using Local Preference

router(config-route-map)#route-map to-AS16030 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-AS16030 out
router(config-router)#exit
router(config)#exit
router#copy running-config startup-config

4. And then, go to www.CiscoNET.com 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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