From: Howard C. Berkowitz (hcb@gettcomm.com)
Date: Wed Nov 13 2002 - 11:38:38 GMT-3
At 5:06 PM -0500 11/12/02, Joe A wrote:
>Group,
>
>I don't 'conclusively' agree with the 'aggregation theory' for this
>reason: say I have network A.A.A.A /24 from ISP A and network B.B.B.B
>/24 from ISP B, and both are chunks out of a class A or B, anything that
>can be aggregated on the ISP's egress. If I also advertise A.A.A.A /24
>to ISP B and B.B.B.B /24 to ISP A, then, assuming they propagate the
>routes I send, their advertisement will be the more specific match, and
>I'd be pulling traffic in exactly opposite of what I expected! I
>haven't seen this to be the case, so I have to disagree that they will
>not propagate a /24. I think if you have a discussion with your
>providers and you all understand your goals, they'll either accommodate
>you or tell you they can't; either way there should not be any
>surprises.
>
>All that aside, these are the problems that the RADB was designed to
>solve, right? Get your routing policy documented in a public database
>so that all providers can easily see your policy and know that you are
>in fact sending out /24s. I'm curious, does anyone out there 'really'
>use the RADB when they do their BGP configs?
>
>Joe
These days, I think most if not all North American carriers use the
public RADB as a reference check. The now-defunct ANS used to
generate all its filters from it, and MCI Internet did use it fairly
extensively.
What these carriers do, however, is mirror the public RADB using irrd
freeware, and then extend it to include their customer information
and their undisclosed peering arrangements. They use it for various
things. At RIPE a couple of years ago, UUnet Europe explained how
thwy fed it into an ORACLE data base. Several programs ran against
this data base, setting up internal communities and filters, and
defining local/regional/etc. privileges for various levels of network
operations staff to change the configuration.
A driver towards more RADB use is that RIPE now requires you to
register your routing policy in their routing registry if you are
granted an AS number. AFAIK, ARIN and APNIC only suggest this.
>
>-----Original Message-----
>From: nobody@groupstudy.com [mailto:nobody@groupstudy.com] On Behalf Of
>Larson, Chris
>Sent: Tuesday, November 12, 2002 10:46 AM
>To: 'Paul Jin'; MADMAN; Hamele Kassa
>Cc: Brian T. Albert; ccielab@groupstudy.com
>Subject: RE: BGP & multihoming
>
>
>Although most ISP's will accept the /24 it is unlikely that they
>propogate it outside of their own AS if the IP block you have was
>provided by the ISP. In that case they will accept /24 but will usually
>aggregate it to neighbors outside of their own AS.
>
>> -----Original Message-----
>> From: Paul Jin [SMTP:pauljin@yahoo.com]
>> Sent: Monday, November 11, 2002 8:05 PM
>> To: MADMAN; Hamele Kassa
>> Cc: Brian T. Albert; ccielab@groupstudy.com
>> Subject: Re: BGP & multihoming
>>
>> I cannot remember who it was for sure, but I had a situation where I
>> got for a customer of ours, to advertise a customer owned /24 to ATT
>> and they had no problems.
>>
>> Everything went fine, and a week or two later, I got a call from the
>> customer saying there is a particular web site that the executive
>> members needed to get to but somehow they could not since the change
>> over to ATT.
>>
>> What we found out was the fact that although ATT took in the /24
>> prefix and readvertised it, there was an ISP few hops down that did
>> not accept /24. and the web server that the customer needed to get to
>
>> was behind that ISP.
>>
>> But I cannot remember who it was, and this was back in early part of
>> 2001.
>>
>> Has anyone had any similar experience?
>>
>> - Paul
>>
>> MADMAN <dave@interprise.com> wrote:I keep seeing people refer to this
>
>> /19 as the smallest aggregate that will be accepted by a provider
>> though I have yet to meet this provider. I have set up several
>> customers with dual home full routes and they announce a single /24
>> network or maybe a couple but very few have /19 or better. The
> > providers I have worked with that accepted the /24 include Qwest, MCI,
>
>> Sprint, Onvoy, and AT&T come to mind.
>>
>> Dave
>>
>> Hamele Kassa wrote:
>> >
>> > Brian,
>> >
>> > You do not need to secure your own registered address/es(your
>> > network
>> has to
>> > be bigger than /19 space to qualify). The IP address/es assigned to
>> > you from your providers (/24 or shorter address space) will work for
>
>> > you as long as you are running BGP(no longer prefix than /24).
>> > However you need
>> to
>> > secure and AS from ARIN(if you are multihomed you will qualify).
>> >
>> > I hope this helps.
>> >
>> > HK
>> >
>> > ----- Original Message -----
>> > From: "Brian T. Albert"
>>
>> > To: "MADMAN"
>> > Cc:
>> > Sent: Sunday, November 10, 2002 10:51 AM
>> > Subject: RE: BGP & multihoming
>> >
>> > > When you say "your own registered address/es", do you mean
>> > > prefixes
>> > assigned
>> > > to you from your 2 providers or obtained from another authority?
>> > > What
>> > other
>> > > authority can assign you prefixes independent of you providers,
>> > > and
>> what
>> > are
>> > > the requirements to obtain them?
>> > >
>> > > BA
>> > >
>> > > -----Original Message-----
>> > > From: MADMAN [mailto:dave@interprise.com]
>> > > Sent: Saturday, November 09, 2002 9:12 PM
>> > > To: Brian T. Albert
>> > > Cc: ccielab@groupstudy.com
>> > > Subject: Re: BGP & multihoming
>> > >
>> > >
>> > >
>> > > You don't need NAT if you have your own registered address/es. No
>> > special
>> > > config required, you simply announce your public address/es
>> > >
>> > > Dave
>> > >
>> > > "Brian T. Albert" wrote:
>> > >
>> > > > In the real world can BGP multihoming to 2 different providers
>> > > > be accomplished without NAT for the internal networks? I have
>> > > > found
>> some
>> > > links
>> > > > on CCO http://www.cisco.com/warp/public/459/BGP-PIX.htm that
>> > > > show
>> how to
>> > > do
>> > > > it with NAT, but is it possible without. If so, can someone
>> > > > supply
>> some
>> > > > config examples or good links.
>> > > >
>> > > > Thanks
>> > > >
>> > > > Brian T. Albert
>> > > > brian.albert@worldnet.att.net
>> > >
>> > > --
>> > > David Madland
>> > > CCIE# 2016
>> > > Sr. Network Engineer
>> > > Qwest Communications Inc.
>> > > 612-664-3367
>> > > dave@interprise.com
>> > >
>>
>> --
>> David Madland
>> CCIE# 2016
>> Sr. Network Engineer
>> Qwest Communications
>> 612-664-3367
>>
>> "You don't make the poor richer by making the rich poorer." --Winston
>> Churchill
>>
>>
>> ---------------------------------
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