From: ccienj (ccienj@hotmail.com)
Date: Fri Jul 02 2004 - 17:34:24 GMT-3
Howard,
This is a practice scenario so I won't worry lot,
the way I know it can be done is that ISP after migration to AS number 200
from 100 can add the command:
router bgp 200
neighbor <customer add> local-as 100
This will avoid any reconfiguration in customer's routers :
router bgp 400
nei <ISP add> as 100
nei <ISP add> ebgp 255
Is there any other way of achieving the same?
thanks.
----- Original Message -----
From: "Howard C. Berkowitz" <hcb@gettcomm.com>
To: <ccielab@groupstudy.com>
Sent: Friday, July 02, 2004 3:20 PM
Subject: Re: BGP AS-Migration
> At 2:54 PM -0400 7/2/04, ccienj wrote:
> >An ISP currently on AS 100 will move to AS 200 next year, to avoid
> >reconfiguration for this year's customer's what would be best solution to
> >minimize reconfiguration.
>
>
> Especially in an ISP context, I caution everybody not to look for
> low-configuration solutions, if they might have ANY effect on your
> peering with the rest of the world. Read RFC2072, my Router
> Renumbering Guide. Get all your configurations onto configuration
> servers so you can do global edits on them, and reload in a
> controlled manner.
>
> This is not a routing beginner problem. Some questions include:
>
> Is the ISP now single-homed to AS100? Will it multihome?
>
> Will you or do you connect to different POPs of the same ISP?
>
> Do you accept default, partial or full routes? If you are not
> multihomed, does this do you any good?
>
> How many edge routers run BGP?
>
> Are there reflectors or confederations?
>
> Does the ISP have its own address space?
>
> Who handles forward and reverse DNS?
>
> Do you have adequate documentation to justify new address assignments?
>
> Are your routes registered in a routing registry? Which one (or
> mirrors)? If not, why not?
>
> Do you have customers running BGP to you? At one or more points?
>
> Do you use any communities defined by your upstream? Do your
> customers use any communities? Who defines them?
>
> Are you present at any multilateral peering points? Do you have any
> private peerings to other ISPs in your area?
>
> Do you have a network management system? What are its capabilities
> for configuration management?
>
>
>
> >
> >I think BGP Local-as would be the best way to handle this any other ideas
?
> >
>
> I don't understand how and where you would apply this, or exactly
> what you mean. A confederation with private AS numbers for most of
> the internal space and customers?
>
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