Re: OT : BGP soft-reconfiguration inbound memory costs

This is precisely what I thought too. I had 3 peers with full feed
configured with the soft-reconfig inboud command. I figured I'd save on ram
by removing it but couldn't see any difference afterwards...

Full feeds were on 12.2(33)SXI. I labbed it up under 12.4(15)T.

Does anybody have any experience with this feature?

Eric

On Sat, Feb 26, 2011 at 4:03 PM, Fabian Pucciarelli <fabiangp_at_gmail.com>wrote:

> My understanding is that when you enable the feature you need enough RAM to
> hold 2x the amount of nlri received from that neighbor. If you receive
> internet full tables you would require a lot of memory, if it is a small
> table you don't require much. I only use the feature to be able to use show
> ip bgp neighbor x received and compare it to show ip bgp neighbor x routes
> when testing inbound filters.
>
> F.
> On Feb 25, 2011 2:22 PM, "eric_at_linux.ca" <eric.lauriault_at_gmail.com> wrote:
> > Hi all,
> >
> > For a long time, word on the street was that "soft-reconfig inbound"
> takes
> > quite a bit of memory and is not as useful as it once was since most BGP
> > implementations have added route refresh capabilities. I've also read
> that
> > "the code has been optimized and that the memory impact is insignificant
> > nowdays". Kinda contradictory. I can't seem to find much information on
> the
> > exact cost in memory of this feature.
> >
> > For some time, we had this feature enabled on a few peers with full
> feeds.
> > One would think that by removing it, we would save quite a bit of ram. We
> > didn't see any quantifiable difference in RAM usage.
> >
> > I've tried measuring the exact cost of this feature in a lab environment
> but
> > the following show commands weren't very helpful :
> >
> > show proc mem | i BGP : the bgp processes seem to take the exact same
> amount
> > of RAM
> > show ip bgp sum : the memory and path/bestpath fields seems to be exactly
> > the same, whether the command is there or not
> > show ip bgp neigh : can't find anything there either
> >
> > Does anybody have any clear understanding of the memory costs of the
> > "soft-reconfiguration inbound" command?
> >
> > Regards,
> >
> > Eric Lauriault, #27521
> >
> >
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Received on Sat Feb 26 2011 - 17:39:46 ART