Hi Venkat,
both type 3 and type 4 are generated by Area Border routers. Type 3 describes routes to networks, also used for aggregating routes. Type 4 describes routes to ASBR. Summary Links (type 3) are identified by the IP network numbers of the destinations they are pointing at. ASBR Summary Links (Summary Links type 4) are identified by the RID of the ASBR. That means that type 3 LSAs cannot carry information regarding the ASBR, and that's why you need a type 4 LSA to reach the ASBR. Since a router in stub area must send a packet to the ABR to reach the ASBR, no matter what the external destination, there is no need to flood type 4 LSAs into a stub area. Hope this helps. Regards, Georg Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=36364&t=36358 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
