[c-nsp] BGP questions

[julien leroiso]

hello,

firstly I'm sorry for my poor english...

I have questions about BGP :

1/ multiple sites and lan2lan failure

I have a network on 2 sites with a lan2lan between them.
To help, apart from my classes interconnection routers (/ 29), my
endusers classes are used only on a single site.

  ISP1 - BGP1 - router1 - class1
              - router2 - class2
          |
          | lan2lan
          |
  ISP2 - BGP2 - router3 - class3
              - router4 - class4


What happens to BGP advertisements if the lan2lan is shut?
Are 2 BGPs will announce all classes, or only IP address on their site ? Is
there a dynamically way to force local address advertisement only ?

2/ latency/packets lost

I have 1 ISP on each site.
I assume 2 sites
  - Are too far to have a suitable latency
  - the lan2lan is bad (packet lost)
So the site1 so by the site2 and vice versa.

Is it possible to use local ISP at each site input AND ouput ?
If the link to the local ISP falls to bypass the lan2lan and another site.