nanog mailing list archives
Re: NAP/ISP Saturation WAS: Re: Exchanges that matter...
From: Vadim Antonov <avg () pluris com>
Date: Mon, 16 Dec 1996 20:58:47 -0800
Craig Nordin <cnordin () vni net> wrote:
Interesting. An ICMP packet dropped when busy. Well, it seems as if there is only a hair's difference between when an ICMP packet is dropped and when an IP packet is dropped.
Well, cisco (and all other known fast routers, for that matter) handles ICMP in software, unlike vanilla IP packets, which are routed with significant hardware assistance. I.e. a lot of ICMPs will overload CPU. It won't interfere with routing of IP packets (though it can wreck havoc with of routing and network management protocols). So cisco limits the rate at which ICMPs are processed.
If you are busy, you are busy, right?
Not. Different pieces of hardware are busy in those cases.
I know that I was getting zero packet loss for many many basic routes this time last year that are now losing packets. I think that a network is in great shape when the packet loss is at a sheer minimum. Even one percent packet loss can be felt as substantially more degraded than perfect transport.
Er. There's no such thing as perfect transport as long as TCP is concerned. If end-hosts support large windows, even a single TCP session will load the network to the point where it'll lose packets.
Just like ra.net, I use pings to monitor one aspect of overall performance. Me and ra.net are not alone.
Pings are ok, as long as you realize what exactly is being measured. If you're pinging ciscos, you aren't measuring IP packet loss. --vadim - - - - - - - - - - - - - - - - -
Current thread:
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Tim Salo (Dec 16)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Dima Volodin (Dec 16)
- <Possible follow-ups>
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... maillists (Dec 16)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Tim Salo (Dec 16)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Tim Salo (Dec 16)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Vadim Antonov (Dec 16)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Craig Nordin (Dec 16)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Chris Caputo (Dec 17)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... David Miller (Dec 19)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Tony Li (Dec 19)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Alex.Bligh (Dec 19)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Tony Li (Dec 19)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Jonathan M. Bresler (Dec 19)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Alex.Bligh (Dec 20)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Jim Van Baalen (Dec 20)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Nathan Stratton (Dec 20)
- Re: NAP/ISP Saturation WAS: Re: Exchanges that matter... Craig Nordin (Dec 16)