North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: PMTU-D: remember, your load balancer is broken
FYI, there are core routers out there that can support line rate HW-based fragmentation. I believe this is necessary in any router with heterogeneous interfaces. Bora ----- Original Message ----- From: <[email protected]> To: "Paul Vixie" <[email protected]> Cc: <[email protected]> Sent: Saturday, June 17, 2000 10:06 PM Subject: Re: PMTU-D: remember, your load balancer is broken > > On Sat, 17 Jun 2000 11:59:30 PDT, Paul Vixie <[email protected]> said: > > [email protected] writes: > > > Has this changed? Has "fragmentation" become a Great Evil, ... ? > > > Yes. http://research.compaq.com/wrl/techreports/abstracts/87.3.html says: > (abstract trimmed) > > Research Report 87/3, December 1987 > > > > 87.3 -- Fragmentation Considered Harmful > > Fragmentation is at best a necessary evil; it > > can lead to poor performance or complete > > communication failure. There are a variety of > > Yeah, I've known about that for a while. What I *meant* was: > > Has fragmentation been reclassified from "necessary evil that can > cause problems" to "Great Evil that must be avoided at all costs"? > > For instance, we probably all agree that fragging on a core router > is Bad Juju and should be avoided if at all possible. On the other > hand, how far should we jump through hoops (such as PMTU-D etc) > to avoid fragging on a last-hop modem link from a terminal server > to a PC? > > I already spend far too much of my day (even with a lot of tools) > sending flame-grams to ISPs who drop us spam, or have open mail relays, > or start running NTP or tools that query ports 13/37 and forget to open > the firewall, and then complain about my machine probing them.. > > Enabling PMTU-D (even if it won't buy *my* boxes that much since their > local MTU is 1500) and getting people to fix their ICMP configurations > for the benefit of those sites that WILL profit is an option, but > only if there's general consensus that it's a fight worth fighting... > > Valdis Kletnieks > Operating Systems Analyst > Virginia Tech >
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