[j-nsp] BGP origination

[Jan Czmok]

dre (andre at operations.net) wrote:
> On Wed, Jan 29, 2003 at 02:17:15AM -0500, Richard A Steenbergen wrote:
> > For example, you have a customer with a /24 implemented as a .1/24
> > address on an interface, and you need to announce that /24 for them.
> > The interface route will override the static route because of
> > preference, the route with the community tags attached will never
> > get into the rib, and the route will never be announced. (or somewhat
> > conversely say the /24 is used inside your network and redistributed
> > via an IGP, the static would win and you would need to specify a
> > working next-hop in your holddown route).
> 
> Don't mix customer prefixes with your own infrastructure addressing.
> Always save at least a few infrastructure addresses for customers,
> namely the preferrably /31 (but is often /30 due to code limitations)
> ptp links, and one loopback per customer (e.g. for bgp router-id per
> neighbor).  keep N for gre, hsrp/vrrp, and other off-one situations
> (plan accordingly; N is often larger with a smaller customer base).
> 
> With proper address planning, you can easily avoid this situation.
> A good policy would be to dictate that customers not implenting BGP
> get static routes only (no customer addressing allowed in your IGP
> ever), but directly to your outgoing interface, while still giving
> them an infrastructure address on (from your perspective) far-end
> interfaces.  You can then classify these customer static routes to
> be redistributed into your IBGP.
> 
> Sorry to go to the competitor's documentation, and I would write
> it in RPSL, but that would mean digressing a little further off-topic.
> This is a very good reference on "access engineering" BGP4+CIDR best
> practices:
> 
> ftp://ftp-eng.cisco.com:/cons/workshops/isp-workshop/StudentCD-Rev-E/Adv_BGP/a3-1up.PDF

Well, so a question from my side arise:

If a customer is having a /24 assigned PI prefix and you have a mixed
network (Cisco/Juniper) AND customer is static routed, how can this be 
archieved without messing things around ?

(currently we use "advertise-inactive" but i'll rather have this clean
running)

IGP is IS-IS
EGP is BGP4

--jan