Dear Madame, dear Sir! Are there any RIPE documents available which describe address assignment strategies for Multi-homed customer (multi-homed to different ISPs): - Does those customers require PI address space? - Does RIPE assign the PI address space (is it a /19 CIDR block)? - If the customer has to use PA address space from ISP A, must ISP B announce prefixes in addition to his CIDR blocks (or is it optional for ISP B to comply with the wishes of his customer with respect to the stability of the global routing system) Regards Edgar Reinke ____________________________________________ Edgar Reinke ExperTeach GmbH Waldstrasse 92 63128 Dietzenbach E-Mail: edgar.reinke@experteach.de
At 16:51 +0200 4/10/00, Edgar Reinke wrote:
Dear Madame, dear Sir!
Are there any RIPE documents available which describe address assignment strategies for Multi-homed customer (multi-homed to different ISPs):
Sections of RIPE 127, RIPE 185 and RIPE 147 come to mind.
- Does those customers require PI address space?
No, if they agree with providers to have the chunk of PA space assigned to them by their LIR announced on the Internet. It takes both the LIR and the other providers to agree on this.
- Does RIPE assign the PI address space (is it a /19 CIDR block)?
Only if necessary. The assignement of PI space is not the preferred option but will be granted if necessary. The size of the assignement depends on the amount of addresses necessary (see RIPE 127, Sections 2 and 3) only.
- If the customer has to use PA address space from ISP A, must ISP B announce prefixes in addition to his CIDR blocks (or is it optional for ISP B to comply with the wishes of his customer with respect to the stability of the global routing system)
Each ISP decides their routing policy. Routing decisions are taken by ISPs not Internet Registries. Hope this helps. Regards, Joao Damas RIPE NCC
Regards
Edgar Reinke
____________________________________________
Edgar Reinke ExperTeach GmbH Waldstrasse 92 63128 Dietzenbach
E-Mail: edgar.reinke@experteach.de
I hope we won't be creating problems for ourselves (transit providers) by causing possible excitement amongst those who have a possible need for multihoming. I further hope that we are not looking to even suggest any kind of recommendation / standardisation document .. as it is difficult and often impossible to explain to clients as to why one won't agree to drilling holes in ones aggregate space and the other can. How many of us have found working, on behalf of our client, with their other provider trying to resolve load balancing issues, a comfortable experience ? There are a number of solutions for multihoming (though not necessarily different providers. As networks grow, most tier 1/2 providers eliminate the existence of single point of failures .. hence, a client can be multihomed between two independent sections of a single providers' network) and the one encouraged most is one where client is not dependent on either one of the providers ie. no need to plug a hole in someone else's aggregate block and their filters. Rush
At 16:51 +0200 4/10/00, Edgar Reinke wrote:
Dear Madame, dear Sir!
Are there any RIPE documents available which describe address assignment strategies for Multi-homed customer (multi-homed to different ISPs):
Sections of RIPE 127, RIPE 185 and RIPE 147 come to mind.
- Does those customers require PI address space?
No, if they agree with providers to have the chunk of PA space assigned to them by their LIR announced on the Internet. It takes both the LIR and the other providers to agree on this.
- Does RIPE assign the PI address space (is it a /19 CIDR block)?
Only if necessary. The assignement of PI space is not the preferred option but will be granted if necessary.
The size of the assignement depends on the amount of addresses necessary (see RIPE 127, Sections 2 and 3) only.
- If the customer has to use PA address space from ISP A, must ISP B announce prefixes in addition to his CIDR blocks (or is it optional for ISP B to comply with the wishes of his customer with respect to the stability of the global routing system)
Each ISP decides their routing policy. Routing decisions are taken by ISPs not Internet Registries.
Hope this helps.
Regards, Joao Damas RIPE NCC
Regards
Edgar Reinke
____________________________________________
Edgar Reinke ExperTeach GmbH Waldstrasse 92 63128 Dietzenbach
E-Mail: edgar.reinke@experteach.de
Hi Edgar, If you are using Cisco routers, check out the conditional advertisement feature. It's not perfect, but at least subprefixes are only leaked to the Internet when there is a failure situation (which usually are few and far between). Also, the multihomed customer doesn't need a public AS, and can use address space from both upstreams. It's documented in IOS Essentials (http://www.cisco.com/public/cons/isp/documents/IOSEssentialsPDF.zip), if it helps. Also I've put some examples of multihoming (including conditional advertisement) in one of the BGP presentations I use for ISP workshops (http://www.cisco.com/public/cons/workshops/bgp/4-Multihoming-6up.pdf). At 16:51 04/10/00 +0200, Edgar Reinke wrote:
Dear Madame, dear Sir!
Are there any RIPE documents available which describe address assignment strategies for Multi-homed customer (multi-homed to different ISPs): - Does those customers require PI address space? - Does RIPE assign the PI address space (is it a /19 CIDR block)? - If the customer has to use PA address space from ISP A, must ISP B announce prefixes in addition to his CIDR blocks (or is it optional for ISP B to comply with the wishes of his customer with respect to the stability of the global routing system)
This third question is causing many folks more and more concern. Routing table is undergoing an explosion in growth at the moment, and from what I can tell, most of it is through multihoming. BGP is an excellent tool, but ill thought out multihoming solutions are becoming our undoing too... philip --
Regards
Edgar Reinke
____________________________________________
Edgar Reinke ExperTeach GmbH Waldstrasse 92 63128 Dietzenbach
E-Mail: edgar.reinke@experteach.de
-------------------------------------------------------- Philip Smith ph: +61 7 3238 8200 Consulting Engineering, Office of the CTO, Cisco Systems --------------------------------------------------------
participants (4)
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Edgar Reinke -
Joao Luis Silva Damas -
Philip Smith -
Rushdul Mannan