BGP Community String for Optus(Singtel) AS7474

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Attention

This BGP Community string information might be outdated. Please contact Optus(Singtel) AS7474 to get more recent one. This BGP communites is ONLY for the customer who has BGP with Optus(Singtel) AS7474. www.ipbalance.com is not maintaining this BGP Community string.

Things to note regarding the Looking Glass are as follows ;

• There are 2 separate routers performing Looking Glass functions :

The Domestic Looking Glass router includes BGP routes for Optus Customers , Optus Internal , and National Peers only.

The International Looking Glass router includes BGP routes for Optus Customers , Optus Internal , and International Peers only

• Important BGP Communities configured by Optus include the following :

BGP Community String 7474:1402 is used for Asian Routes
BGP Community String 7474:1403 is used for US Routes
BGP Community String 7474:1202 is used for NSW Customer Routes
BGP Community String 7474:1203 is used for VIC Customer Routes
BGP Community String 7474:1204 is used for QLD Customer Routes
BGP Community String 7474:1205 is used for SA Customer Routes
BGP Community 7String 474:1206 is used for WA Customer Routes

Customers can also override BGP Local Preference in AS7474 by announcing the following BGP Communities with their routes –

BGP Community String 7474:100 is used for Customer routes to set BGP Local Preference to 100 (the default Local Preference for customer routes)
BGP Community String 7474:90 is used for Customer routes to set BGP Local Preference to 90
BGP Community String 7474:80 is used for Customer routes to set BGP Local Preference to 80
BGP Community String 7474:70 is used for Customer routes to set BGP Local Preference to 70

• These Routers do not have links into each Optus Router. They consist of simply a Ethernet interface to plug it into the network. As such, ping’s & trace’s will always take the same path. Ping’s and trace’s are only really useful for verifying IP connectivity to a host, and do not demonstrate accurately the path the packets will take from other routers in our network. RADB requests are done realtime by opening a port 43 connection to whois.radb.net and are not results from a local cached database or similar. nslookup, dig and all other DNS resolution is done off a DNS resolver at 202.139.124.225 where no domains are hosted (caching-only nameserver).

 

 

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.