OpenAccess Network Services
Get connected... Stay connected...

SpeedTest | MyAccount | WebMail | Tech Bulletin
    Internet     Hosting     Telephone     Security     Support     Company     Community    
Support  > Policies  > BGP  > Dampening 

OpenAccess BGP Dampening Policy
OpenAccess uses BGP dampening in our network to limit the impact of problems localized to a particular network and promote the stability of the global internet.

Historically, route flaps occur with a greater frequency for small prefixes. OpenAccess BGP dampening is stepped to be increasingly aggressive as prefixes become equal to or smaller than /18, /21 and /24.



Term ge /17 le /18 le /21 le /24 Meaning
Dampen To suppress the routing announcements from customer networks.
Filter All customer routing announcements are passed through filters which limit the announcements in some way. The normal filter is applied to limit the addresses that can be announced; however, when a customer network is changing rapidly such that the routing announcements are being added and removed frequently, BGP will implement the dampening filter which will prevent propagation of the changes into the backbone until the network is stable.
Half-life time Once the route has been assigned a penalty, the penalty is decreased by half after the half-life period. Currently, a half-life time of 15 minutes is used in the network.
Maximum suppress time This is the maximum number of dampen-period doublings allowed (the dampen-period is increased by the half-life time with each flap after the third one). Currently, a maximum suppress time of 30 minutes, or 2 doublings, is used in the network.
Penalty A numeric value that is assigned to a route when it flaps. Currently, a penalty of 1000 is set for each flap.
Reuse limit A configurable numeric value that is compared with the penalty. If the penalty is less than the reuse limit, a suppressed route that is up will no longer be suppressed. Currently, a reuse limit of 1500 is used in the network.
Route flap The withdrawal and subsequent announcement of a route over an eBGP session.
Suppressed A route that is not used or filtered even though it has been announced.
Suppress limit A numeric value that is compared with the penalty. If the penalty is greater than the suppress limit, the route is suppressed. Currently, a suppress limit of 3000 is used in the network.


The Route Dampening Process:

A route that is flapping receives a penalty of 1000 for each flap. When the accumulated penalty reaches a configurable limit, BGP suppresses advertisements of the route even if the route is announced. The accumulated penalty is decremented by the half-life time. When the accumulated penalty is less than the reuse limit, the route is advertised again if it has not been withdrawn.

For example, a route with a penalty of 3000 will take the half-life time of 15 minutes to cut the penalty in half and reach the reuse penalty of 1500, at which point the route will be advertised again. Similarly, a route with a penalty of 6000 will take 15 minutes to cut the penalty in half and reach a penalty of 3000. It will then an additional 15 minutes to cut the penalty in half again and reach the reuse penalty of 1500. The total decay time from 6000 to 1500 (i.e., reuse) with a half-life time of 15 will be 30 minutes. Please see RFC 2439 for more details.

Whats New?

2010.11.01 Digital telephone & PBX services expanded
Over the summer of 2010 OpenAccess has rolled out digital telephone service for ourselves, affiliated companies and a few customers who were willing to be 'guinea pigs'.  Overall things went better than we expected and we are now opening up our digital telephone service plans to more customers.

2010.10.21 IPv6 Transition
OpenAccess will be having a mid range time line for adoption and implementation of IPv6.  As most people know who are reading this, there is a certain 'chicken & egg' problem with IPv6 in as much for any organization to move to IPv6 requires that other organizations have moved to IPv6.

2010.07.15 NAS.COM wholesale VPS and WebHosting services
This fall, OpenAccess will be re-purposing the '' domain name to provide VPS and WebHosting services, primarily wholesale to web developers. If you have an e-mail address, or a personal website located at, those services will continue be supported although we will not be accepting new accounts.

2010.02.22 Joomla auto install wizard now available.
Due to popular request, we now have a Joomla auto-installer available on our newer cPanel® servers.  This allows customers to quickly and easily install Joomla on their website.  The auto-installer is available under the 'site software' section in the administrative interface of your webhosting account.

2009.10.25 OpenAccess begins internal testing for Windows 2008 Server hosting solutions.
OpenAccess is happy to finally be able to announce that we are beginning internal testing of cPanelŽ/Enkompass as a platform for our customers to be able to deliver Windows(c) 2008 Server solutions on.

2007.09.26 Changes in paper billing system.
Effective January 1st 2008 we will be doing what most of our competitors have been doing for years and adding a $1.00 surcharge for paper invoices.

2007.05.30 New web servers in production.
In May we got two new web servers in production. These machines are based out of our facilities in Seattle and were needed as we have about hit capacity on our existing webhosting infrastructure.

2007.03.15 Additional nationwide and global network capacity added.
OpenAccess is glad to announce that we have put into production a new circuit providing us with direct Tier-1 nationwide and global Internet transport.

2007.01.17 Verizon DSL speed upgrades complete
Today we did the work to convert all NAS.COM customers over to our faster connection into Verizon. Everybody should be seeing performance increases.

More News...

(c) 1998-2012 OpenAccess Network Services
P.O. Box 4220, Bellingham, WA 98227
Bellingham/Whatcom (360) 647-0785 Toll Free: (800) 882-4979

OpenAccess is now part of the family.