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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical LoadBalancing products: Foundry ServerIron
The Foundry solution (ServerIron) is not BGP based. It is a DNS-based solution that uses a round-trip-time metric (calculated based on TCP syn/ack from client to server by the ServerIron on a per connection basis). The two down-sides of a DNS based solution are both caused by the fact that client source IPs are not contained in the request that comes from the client DNS resolver: 1] persistant connections must be managed on each real server. 2] client's whose IP is not within the same netblock (defaults to /20, tuneable) as DNS resolver do not get the benefit of RTTmetrics. Peter At 6:10 PM -0400 7/5/00, Dmitri Krioukov wrote: >the major disadvantage of the foundry (bgp) >solution is longer prefix injection. > >the major problem with the dns-based solutions is >that they're not topology-aware (-> suboptimal >routing). attempts to make dns smart lead to >rather awkward reverse pinging configurations >and proprietary protocols running between load >balancers. (there was also rfc2052 by paul vixie >but it required modification of dns clients.) > >there is also the "triangle data flow" solution, >which is broken by cef... > >i'm in the process of preparing an overview >of the available techniques along with introduction >of a new one, which solves a lot of headaches. >it requires a feature set that is not available >on any of the currently existing lb platforms, >hence, for testing, i had to develop one using >open source (i chose linux to make it fast (it >had almost all bits in place -- check >http://www.linuxvirtualserver.org/)). >-- >dima. > >> -----Original Message----- >> From: [email protected] [mailto:[email protected]]On Behalf Of >> tony bourke >> Sent: Wednesday, July 05, 2000 2:11 PM >> To: Jeremiah Kristal >> Cc: [email protected] >> Subject: Re: bad idea? >> >> >> >> actually, Foundry has a global solution based on BGP, check them out. >> >> There is a load-balancing mailing list, which addresses such issues. >> >> http://vegan.net/lb is the info to sign up. >> >> Tony >> >> On >> Wed, 5 Jul 2000, Jeremiah Kristal wrote: >> >> > >> > Given a small, globally routable netblock to be used for front-end web >> > servers, and a strong aversion for using DNS for any type of load >> > balancing, would it be reasonable to build two identical servers farms >> > with the same public IP addresses and rely on the BGP sessions with the >> > hosing providers to remove one advertisement in the event of a problem? >> > I've been looking at ways to ensure that the webservers are always >> > available, short of building a network connecting hosting facilities. >> > >> > Jeremiah >> > being a customer stinks >> > >> >> -------------- -- ---- ---- --- - - - - - -- - - - - - - >> Tony Bourke [email protected] >> >> >> >>
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