From: Rob Pickering (robIZZATrpanetwork.co.uk)
Date: Tue Feb 25 2003 - 11:35:34 EST
I think the point is that whilst in practice sending out replies with
very short TTLs is unlikely to break things, it probably doesn't
*guarantee* convergence in seconds on link failure either.
If you budget for convergence times closer to 10 mins with occasional
stragglers like big ISP web-caches holding the "old" address for HTTP
then this is a more reasonable expectation for the technology.
--On 25 February 2003 15:30 +0100 Joerg.FritschIZZATtesion.de wrote:
> Hello, > > on the market there are numerous products (i.e. alternatives to > BGP) which do WANLink LoadBalancing based on DNS and NAT. Radware > LinkProof, RainConnect, Nortel WanLinkLB. These products all work > with very low TTLs and I haven't heared of any big problems yet! I > think some of the arguments against low TTLs might be esoteric. > > However vendors usually recommend TTLs around 60s. You can watch > such low TTLs when doing > 'dig a1974.g.akamai.net' or 'dig www.zdf.de' several times. In the > answer section they have a TTL of 20s which you see decreasing with > several subsequent dig-commands. > > It is kind of interesting ;-))) > > --Joerg > http://www.firewalls-illustriert.de > > > -----Ursprüngliche Nachricht----- > Von: Anders Marius Jřrgensen [mailto:listsIZZATanders-marius.dk] > Gesendet: Dienstag, 25. Februar 2003 11:12 > An: lb-lIZZATvegan.net > Betreff: [load balancing] Redundany datacenters (TTL=0) > > > - Whats the Internet / dns community attitude to using a low TTL > value (e.g 0) > ____________________ > The Load Balancing Mailing List > Unsubscribe: mailto:majordomoIZZATvegan.net?body=unsubscribe%20lb-l > Archive: http://vegan.net/lb/archive > LBDigest: http://lbdigest.com > MRTG with SLB: http://vegan.net/MRTG > Hosted by: http://www.tokkisystems.com >
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