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Internet packet loss statistics

Hello,

I am looking for statistics about packet loss in the internet, with references to the sources of information.

1. What is average packet loss on Internet? (http://mpls-experts.com/blog/?p=18 says 4% but how do they know?)

2. I understand packet loss may occur because of a) excessive volume of traffic; b) bit errors or full link failure; c) bgp route convergence. How long does it takes for the routers to notice a problem and reroute the traffic?

3. If for whatever reason Internet route changes (planned maintenance) what kind of packet loss it incurrs?

Separate statistics globally/per region and for hosted severs/broadband subscribers will be greatly appreciated.

Thank you.
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rfc1180
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1. statistic gather from http://www.internetpulse.net/ (Not saying this is what they use, but you need to gather data from all points of the globe).

2. It is not when they know, but how long it takes for updates to reach them; this is hard to say, but typically with BGP , anyhwere from 30 seconds to about a minute and a half (I have seen longer, and I have seen shorter. Then you will also have to consider the IGP that a provider or customer is running internally.

3. This is dependant on if the maintenance is IGP/EGP related; in either case packet loss or latency can occur (is there redundant equal cost paths, are hold-timers high, are the protocols being shutdown gracefully?). There are many variables on this one and is hard to say.

Billy
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gremwell

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Could you possibly clarify the following.

Suppose a link between two routers is overloaded and the traffic gets dropped. Even if packet loss is noticeable (say 5%), chances are BGP keepalive will go through and nothing will change. It is up to the ISPs to monitor their links and reroute traffic. Is my understanding correct or there is some automatic mechanism which will do the same?

I suppose the same goes for faulty link loosing packets because of bit errors. Should packet loss become really extreme and BGP keepalives don't come in, the router will drop the route and send around appropriate BGP updates. I understand this process is controlled by BGP keepalive interval which is typically 180s. On top of this goes average 30s for BGP propagation you mention. But this happens only if things go really really bad -- TCP (used by BGP) was unable to deliver anything in 3 minutes. Is this correct?

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