At 5:00 PM +0000 12/3/02, p b wrote: >One of the cisco press books indicates one should use >type 1 externals when the route is being advertised by >>1 ASBR and type 2 externals when there's a single >ASBR.
This is just plain wrong. The reason you have E1 and E2 is to have different routing policies. E1 enforces a closest-exit policy which gives a degree of load sharing. E2 enforces a best-exit policy. For example, you might have one fast link to an ISP and one dial backup link, or a primary and a backup provider. In both cases, you want an E2 because you always want to go to a specific exit UNLESS there is a failure. > >Are there any issues if one uses type 1 external even >when the route is being advertised by a single ASBR? It >would seem useful, given the cost to the external is >compatible with the costing used in the OSPF network, to >use type 1 externals even if the route originates from a >single ASBR. The benefit being able to get a meaningful >cost value to the external. Why? If there's only one connection to the outside, does the internal cost really matter if you have to go there? > >Is there any unexpected issues which might arise when >doing this? Flooding of LSAs or SPF aren't imapcted >if a route is an E1 or E2, right? > >Thanks Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=58466&t=58454 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
