Multihoming for the small ISP ( search engine) ala 2005
Greetings folks, (It's been a long time :) I have some questions about multihoming that I can't seem to find by Google-ing for answers 1.) What ever happened to (Avi Freedman's?) Multihoming strategy using DNS(?), there are links to archives circa 1997 but nothing recent. 2) What is the "preferred or correct" way for a relatively small outfit (a small search engine) to implement Multihoming? Especially when most of the machines are a VLS cluster so we are not talking about a large address space here. It seems the outfit is having difficulty getting blocks that they can even run BGP with, (I know I'm missing a lot here) They can't even fill a /24, let alone anything greater :) I am willing to take my answers off line. I'm sure there is a way to do this that is so trivial to folks on this list that it's not talked about, but since I haven't done this type of thing in about 5 years I am really out of the loop. Thanks in advance and for all the great work over the years! Cheers Geoff White
On Mon, 28 Feb 2005, Geoff White wrote:
2) What is the "preferred or correct" way for a relatively small outfit (a small search engine) to implement Multihoming? Especially when most of the machines are a VLS cluster so we are not talking about a large address space here. It seems the outfit is having difficulty getting blocks that they can even run BGP with, (I know I'm missing a lot here) They can't even fill a /24, let alone anything greater :)
Doesn't matter. Assuming we're talking about ARIN-region, if they're multihomed, one of their providers can assign them a /24 (even if they'll only use 2 IPs) so that they can announce that /24 to their other providers and have a chance of not being route filtered. ARIN rules specifically permit this, and it won't be held against the provider when they apply for more space. ---------------------------------------------------------------------- Jon Lewis | I route Senior Network Engineer | therefore you are Atlantic Net | _________ http://www.lewis.org/~jlewis/pgp for PGP public key_________
On Mon, 28 Feb 2005, Geoff White wrote:
2) What is the "preferred or correct" way for a relatively small outfit (a small search engine) to implement Multihoming? Especially when most of the machines are a VLS cluster so we are not talking about a large address space here. It seems the outfit is having difficulty getting blocks that they can even run BGP with, (I know I'm missing a lot here) They can't even fill a /24, let alone anything greater :)
As long as they have a /24 that they can announce, two or more upstreams that are able and willing to establish BGP sessions with them and a router with enough memory to hold at least 2 full views (for a Cisco, you probably want 256MB or more these days), they can multi (or dual) home. I don't think Verio, Sprint or any other major ISP is filtering out /24s from any part of IP4 any more. I don't think there are many ISPs willing to establish BGP sessions for customers that aren't spending at least T1 prices with them. Verizon is going to be rolling out cheap, multimegabyte fiber connections to business and residential customers around here soon. Since I'm paying ~$2k/mo for 2 T1s (with longish loops and a /21), it's tempting to see if I could get ahold of somebody over there willing to talk about BGP :) James Smallacombe PlantageNet, Inc. CEO and Janitor up@3.am http://3.am =========================================================================
As long as they have a /24 that they can announce, two or more upstreams that are able and willing to establish BGP sessions with them and a router with enough memory to hold at least 2 full views (for a Cisco, you probably want 256MB or more these days), they can multi (or dual) home.
They many not need anything near 2 full tables. A default plus providers own and customer routes could do, and would require less memory/smaller router. James H. Edwards Routing and Security Administrator At the Santa Fe Office: Internet at Cyber Mesa jamesh@cybermesa.com noc@cybermesa.com http://www.cybermesa.com/ContactCM (505) 795-7101
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