nanog mailing list archives
Re: Alternatives to GSLB ?
From: Matthew Petach <mpetach () netflight com>
Date: Tue, 5 Apr 2011 13:01:54 -0700
On Tue, Apr 5, 2011 at 12:17 PM, Jack Carrozzo <jack () crepinc com> wrote:
Anycast works.
...with some caveats.
[...] we are looking for ideas onhow to 1) ensure clients are routed to the closest geographical server 2) ensure the client hits the server(s) with the shortest path.No need to deal with that yourself when BGP eats that problem for breakfast lunch and dinner. -Jack Carrozzo
Note that anycast can and will bite you in the ass repeatedly as you deploy it over wider and wider scopes, unless you take careful steps to overcome the differences in policies and coverage areas with different networks. Classic problem: You peer with network X in the US. You buy transit from network Y in Asia. Network Y buys transit from network X in the US. Network X localprefers customer routes over peer routes. Your anycast traffic from network X in the US is suddenly being served from your Asia nodes behind network Y, because network X prefers the path to your anycast subnet heard through their customer instead of the peer-learned path directly from you. Not saying it won't work; it just takes careful planning, judicious use of BGP communities to limit route propagation, and constant monitoring and adjusting as networks change who they purchase connectivity from over time. Matt
Current thread:
- Alternatives to GSLB ? Jeff Blaum (Apr 05)
- Re: Alternatives to GSLB ? Jack Carrozzo (Apr 05)
- Re: Alternatives to GSLB ? Matthew Petach (Apr 05)
- Re: Alternatives to GSLB ? George Herbert (Apr 05)
- Re: Alternatives to GSLB ? Patrick W. Gilmore (Apr 05)
- Re: Alternatives to GSLB ? George Herbert (Apr 05)
- Re: Alternatives to GSLB ? Matthew Petach (Apr 05)
- Re: Alternatives to GSLB ? Jack Carrozzo (Apr 05)
- Message not available
- Re: Alternatives to GSLB ? Jeff Blaum (Apr 11)