[j-nsp] JUNOS Equivalent to CISCO IOS next-hop-self

[Michael Lyngbøl]

On 15.12.2003 15:51:14 +0000, Jeff Wheeler wrote:
> I question the utility in using next-hop-self on internal sessions, or
> even eBGP import policy-statements. In my ASes, I keep the remote (/30)
> next-hop and import the /30s into my IGP. This allows me to tweak the
> metrics on those /30s as another means of controlling my egress paths.

BGP MED or IGP metric to next-hop (router loopback). Only set
next-hop-self on the eBGP ingress router, not on iBGP sessions.

For eBGP peering session over a common IX LAN this practice is bad as
you would carry, say, 195.66.225.254/23 as BGP next-hop; what happens if
some one happens to inject 195.66.225.254/24 into your routing table?

> When you rewrite learnt next-hops to the addresses of your own routers,
> you lose the ability to influence the IGP-cost step in BGP best-path
> selection based on the specific eBGP peer.

You would still choose the shortest IGP path to the next-hop (loopback
address on egress router) if you overwrite next-hop on ingress.

/Michael

-- 
Michael Lyngbøl -- michael at lyngbol dot dk
Network Architect, AS3292 TDC, IP·backbone