BGP Community String for Cablevision Systems AS6128

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Attention

This BGP Community string information might be outdated. Please contact Cablevision Systems AS6128 to get more recent one. This BGP communites is ONLY for the customer who has BGP with Cablevision Systems AS6128. www.ipbalance.com is not maintaining this BGP Community string.

 

BGP Community String

AS Prepend

BGP Community String	Set By	Description
6128:0	CST	Do NOT export to *any* external peer
6128:1	CST	prepend 6128 once at non-customer borders/private peers
6128:2	CST	prepend 6128 twice at non-customer borders/private peers
6128:3	CST	prepend 6128 thrice at non-customer borders/private peers

Local Preference

BGP Community String	Set By	Description
6128:95	CST	Local Preference for directly connected, non-customer networks. [non-customer default]
6128:100	CST	BGP Customer Local Preference [customer default]
6128:110	CST	BGP Customer Local Preference 110
6128:120	CST	BGP Customer Local Preference 120

Export Rules

BGP Community String	Set By	Description
6128:600	CST	Do NOT export announcement to transit peers
6128:610	CST	Do NOT export to public peers [send to transit and public peers]
6128:666	CST	Do NOT export to non-customer peers [send to customer peers only]

 

 

Applying BGP Community string with sample configuration

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.