Anycast 101

Joe Shen joe_hznm at yahoo.com.sg
Mon Dec 20 13:41:05 UTC 2004


Hi,

That's what I want to discuss about. The paper gives a
very detailed explanation on anycast with OSPF_ecmp,
and what I want to know is: 

is there anything not included in it but must be
considered carefully when anycast cache server farm is
to be established in MAN ? 

Will there be any problem with OSPF-ECMP convergence ?
is there any request with DNS software(BIND, CNS,
powerdns etc. ) selection?

Considering such a situation, a big ISP want to set up
hierachical cache DNS service, it has several MAN
interconnected by backbone. each MAN uses a reserved
ASN. The backbone has a public ASN and connect to each
MAN with e-BGP. Should BGP multipath be considered ?
or should each MAN announce same DNS server address
block in each e-bgp session ? will there be any
possible problem in such situation? 

what I do care about is, convergence speed,
reliablity, load balancing within cache server farm,
or load sharing between different cache server farm
when one of them failed, cost of administration.

Joe


> 
> Also, be mindful of ECMP.
> 
>    http://www.isc.org/pubs/tn/isc-tn-2004-1.html
>    http://www.isc.org/pubs/tn/isc-tn-2004-1.txt
> 
> 
> Joe
>   
> 
>  

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