BGP Community String for GlobalaXs AS9009

   February 25, 2007  Leave a comment

Attention

This BGP Community string information might be outdated. Please contact GlobalaXs AS9009 to get more recent one. This BGP communites is ONLY for the customer who has BGP with GlobalaXs AS9009. www.ipbalance.com is not maintaining this BGP Community string.

 

BGP Community String List


BGP Communities to determine the origin of the route in AS9009.

9009:10nn – Own Prefix originated in country code nn
9009:21nn – Prefix originated by customer in country code nn
9009:4100 – Prefixes received at BNIX
9009:4200 – Prefixes received at AMS-IX
9009:4300 – Prefixes received at FREEBIX
9009:4400 – Prefixes received at FREEIX
9009:4500 – Prefixes received at DECIX
9009:4600 – Prefixes received at LINX
9009:4700 – Prefixes received at LIPEX

9009:6774 – Prefixes recieved on private peering Belgacom ICS
9009:6320 – Prefixes recieved on private peering Telecomplete


GlobalaXs Communications has a strict peering policy
Our policy is reflected on http://www.gbxs.net/peering

 

GlobalaXs is doing in and outbound filtering.
Please note we do not accept prefixes longer then /25 and will not reannounce prefixes longer then /24.

 

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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