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NTT/Verio AS2914 BGP Community String


This BGP Community string information might be outdated. Please contact NTT/Verio AS2914 to get more recent one. This BGP communites is ONLY for the customer who has BGP with NTT/Verio AS2914. Also, Showipbgp.com is not maintaining this BGP Community string.

Verio BGP customers may choose to affect our local preference on their routes by marking their routes with the following BGP communities:

BGP Community String Local Prep
(default) 120 Customer
2914:490 120 Customer default
2914:480 110 Customer backup
2914:470 100 Peer
2914:460 98 Peer backup
2914:450 96 Customer fallback

Verio BGP customers may choose to prepend to all Verio peers with the following BGP communities

BGP Community String Prepend AS Description
2914:429 -
Do not advertise to any peer
2914:423 2914 2914 2914 Prepends o/b to peer 3x
2914:422 2914 2914 Prepends o/b to peer 2x
2914:421 2914 Prepends o/b to peer 1x

Verio BGP customers may choose to prepend to all other Verio BGP customers with the following BGP communities

BGP Community String Prepend AS Description
2914:413 2914 2914 2914 Prepends o/b to customer 3x
2914:412 2914 2914 Prepends o/b to customer 2x
2914:411 2914 Prepends o/b to customer 1x

Verio BGP customers may choose to prepend to selected tier 1 peers with the following BGP communities, where nnn is the tier 1 peer's ASN.

BGP Community String Prepend AS Description
65500:nnn - Do not announce to tier 1 peer
65501:nnn nnn Prepend o/b to tier 1 peer 1x
65502:nnn nnn nnn Prepend o/b to tier 1 peer 2x
65503:nnn nnn nnn nnn Prepend o/b to tier 1 peer 3x

Verio sends routes to customers marked with the following communities


BGP Community String Interpretation
2914:410 Verio and customer routes
2914:420 Peer routes
2914:20-- North American country origins
2914:2000 US
2914:22-- European country origins
2914:2201 uk
2914:2202 de
2914:2203 nl
2914:2204 fr
2914:2205 es (Spain)
2914:24-- Asian country origins
2914:2401 jp
2914:2402 au
2914:2403 hk
2914:2404 tw
2914:2405 kr
2914:2406 sg
2914:2407 my
2914:3--- world region origins
2914:3000 North America
2914:3200 Europe
2914:3400 Asia


BGP IPv4 peer filter policy


    • Verio accepts only those prefixes of length /24 and shorter from traditional class A, B, and C space.
    • Verio uses max-prefix filters at most public exchanges. The max-prefix filter is set to 110% of the greater of the following values:
      • number of prefixes announced in the last 24 hours
      • number of prefixes registered in the routing registries under the peer's as-set if this number is less than 5000.


    • Verio will accept any properly registered prefix from our customers but will announce only /24 and shorter prefixes to our peers.
    • All Verio's announcements are registered in one of the routing registries and included under as-set AS-VERIO.

Verio reserves the right to modify this policy without prior notice.


BGP IPv6 peer filter policy

The following is Verio's filtering policy with its peers:


      • Verio accepts /19 through /32, and /35 from 2001::/16 (global unicast allocations)
      • Verio accepts /19 through /32 from 2003::/16 (RIPE allocations)
      • Verio accepts /24 from 3ffe::/18, /32 from 3ffe:4000::/18, and /28 from 3ffe:8000::/20 (6bone allocations; until 6/6/2006 per rfc3701)
      • Verio accepts 2002::/16 (6to4 prefix)


    • Verio will announce /48 and shorter prefixes to our peers.

Verio reserves the right to modify this policy without prior notice.


Verio Routing Registry

Verio requires that all customer BGP routes be registered in either Verio's routing registry, or one of the Internet routing registries mirrored by Verio. The current list of mirrored registries is:
    altdb apnic arcstar bell enterzone gt host level3 radb rgnet ripe savvis sinet
Verio customers are welcome to register their objects in our registry. Look here for more info on our Registry.


Route Dampening

Route dampening is a BGP feature designed to minimize the propagation of flapping routes across an internetwork. A route is considered to be flapping when it is repeatedly available, then unavailable, then available, then unavailable, and so on.


The Route Dampening Process:


The route dampening feature minimizes the flapping problem as follows.

Suppose a route in network A flaps. A route that is flapping receives a penalty of 1000 for each flap and moves it to "history" state. When the route flaps so often that the penalty exceeds a configurable suppress limit, the router stops advertising the route, regardless of how many times it flaps. Thus, the route is dampened.

The accumulated penalty is decremented by the half-life time. When the accumulated penalty is less than the reuse limit, the dampening information for the route is removed and the route is advertised again.

Verio sets different dampening parameters for different sizes of address blocks across the network.

a) For /24 and longer prefixes: max=min outage 60 minutes half-life = 30 Maximum suppress limit = 60 Reuse limit = 820 Suppress limit = 3000

b) for /22 and /23 prefixes: max outage 45 minutes but potential for less because of shorter half life value - minimum of 30 minutes outage Half-life = 15 Maximum suppress limit = 45 Reuse limit = 750 Suppress limit = 3000

c) all else prefixes: max outage 30 minutes min outage 10 minutes Half-life = 10 Maximum suppress limit = 30 Reuse limit = 1500 Suppress limit = 3000


Understanding Route Dampening Terms:

The following terms are used when describing route dampening:

    • Flap - A route is available, then unavailable, or vice versa.


    • History state - After a route flaps once, it is assigned a penalty and put into "history state," meaning the router does not have the best path, based on historical information.


    • Penalty - Each time a route flaps, the router configured for route dampening in another AS assigns the route a penalty of 1000. Penalties are cumulative. The penalty for the route is stored in the BGP routing table until the penalty exceeds the suppress limit. At that point, the route state changes from "history" to "damp."


    • Damp state - In this state, the route has flapped so often that the router will not advertise this route to BGP neighbors.


    • Suppress limit - A route is suppressed when its penalty exceeds this limit. The default value is 2000.


    • Half-life - Once the route has been assigned a penalty, the penalty is decreased by half after the half-life period (which is 15 minutes by default). The process of reducing the penalty happens every 5 seconds.


    • Reuse limit - As the penalty for a flapping route decreases and falls below this reuse limit, the route is unsuppressed. That is, the route is added back to the BGP table and once again used for forwarding. The default reuse limit is 750. The process of unsuppressing routes occurs at 10-second increments. Every 10 seconds, the router finds out which routes are now unsuppressed and advertises them to the world.


    • Maximum suppress limit - This value is the maximum amount of time a route can be suppressed. The default value is 4 times the half-life.

The routes external to an AS learned via IBGP are not dampened. This policy prevent the IBGP peers from having a higher penalty for routes external to the AS.





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 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
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


router(config-route-map)#set community [ISP AS]:3 <------- using AS prepending
router(config-route-map)#route-map [to-ISP] permit 20

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#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.



* We do NOT support or maintain any BGP community string
** Contact ISP to get more detail information

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