>You're probably referring to Cisco's early BGP
>implementation in IOS where the BGP Scanner process ran
>every 60 seconds (although it could be tuned to run at much
>shorter intervals).
>
>Software has come a very long way since then, Ramesh, and
>IOS, in particular, has benefited quite a bit. Gone is the
>BGP Scanner, which has since been replaced by Next Hop
>Address Tracking. Next Hop Address Tracking has also been
>superseded by PIC (Prefix Independent Convergence).
>
>All these improvements in software have meant convergence
>times for BGP have improved greatly, and the 60-second
>crunch routers have to do is no longer necessary provided
>they are running the software that supports these new
>features.
Hi Mark, agree, there is lot of
improvement in SW coding. Cisco has also improved in XOR release. However,
number of routers running XOR is very low. Cisco as market leader runs
same process in IOS used in most of routers at present. Same is with other
vendors and impact possibly may be different.
There is no intention of summarizing
routers available in different AS.
regards
Ramesh Chandra | GM – Network Engineering | NSG | Bharti Airtel Limited
| Phone# +91 124 4243897, 9810300704
----- Forwarded by Ramesh
Chandra/India/Airtel on 08/22/2011 10:56 AM -----
> Appreciate your query and let us look at simple
> Engineering example for a Enterprise house. One
> Enterprise customer manage 10 IP pools allocated to him
> as per his business demand in previous years. He is
> announcing these 10 routes in BGP to upstream carriers,
> NAP/NIXI and other private peering he has with others.
> Every connected BGP listner has to process every 60
> seconds these 10 routes and install in routing table and
> this continues to thousands of routers in Internet.
You're probably referring to Cisco's early BGP
implementation in IOS where the BGP Scanner process ran
every 60 seconds (although it could be tuned to run at much
shorter intervals).
Software has come a very long way since then, Ramesh, and
IOS, in particular, has benefited quite a bit. Gone is the
BGP Scanner, which has since been replaced by Next Hop
Address Tracking. Next Hop Address Tracking has also been
superseded by PIC (Prefix Independent Convergence).
All these improvements in software have meant convergence
times for BGP have improved greatly, and the 60-second
crunch routers have to do is no longer necessary provided
they are running the software that supports these new
features.
> If these 10 pools become one continuous block then these
> thousands of routers shall scan and install one route
> instead 10 routes in previous case under that AS. This
> helps to reduce few CPU cycles and these CPU cycles
> become significant when we talk thousand routers
> repeating the same.
Unless you're talking about route crunching within a single
AS, I'd be more concerned about one router processing
thousands of routes, as opposed to a thousand routers - each
in a different AS - processing a handful of routes.
> Lesser routes in BGP required less
> time to install and hence faster Convergence time.
> Presently, convergence time for 10k IPv4/Ipv6 routes
> takes approx 1 second. Convergence time shall reduce
> significantly when everyone summarise their own routes
> before announcing.
Agree, but do you think it is feasible that an entire
country, made up of several ISP's, can announce a single
IPv6 allocation to the Internet? Serious question.
Mark.
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