Re: [j-nsp] Junos OSPF Inter-Area Routes !
> Recently I was working on a scenario in OSPF for checking the use of > Backbone Area 0 for Inter-Area communication and I was surprised to see > that 2 Non-Backbone areas were able to exchange inter-area routes without > any Area 0 configured. Well the same thing did not work in Cisco which was > the expected behavior per documentations. > > Topology was simple > > R1-Area3-R2-Area2-R1 > > Can anyone help to understand the above behavior in Junos. The Junos ABR will create a type 3 LSA for all connected areas, so you will see the inter-area routes. Now, if in one area you add another ABR, and that ABR also connect to area 0, there is a loop detection mechanism that will make that ABR only process type 1 and 2 LSAs in the other areas - and use type 3 LSAs only in area 0. All this happens in the SPF algorithm, while the LSA may still be in the database. (The Juniper course AJSPR has a chapter on it.) ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
Re: [j-nsp] Junos OSPF Inter-Area Routes !
Active Backbone Detection http://www.juniper.net/techpubs/en_US/junos9.6/information-products/topic-collections/config-guide-routing/routing-configuring-ospf-areas.html Active backbone detection enables transit through an area border router with no active backbone connection. HTH Rgds Alex - Original Message - From: "vaibhava varma" To: Sent: Friday, December 09, 2011 8:43 AM Subject: [j-nsp] Junos OSPF Inter-Area Routes ! Dear All Recently I was working on a scenario in OSPF for checking the use of Backbone Area 0 for Inter-Area communication and I was surprised to see that 2 Non-Backbone areas were able to exchange inter-area routes without any Area 0 configured. Well the same thing did not work in Cisco which was the expected behavior per documentations. Topology was simple R1-Area3-R2-Area2-R1 Can anyone help to understand the above behavior in Junos. -- Regards Varma ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
[j-nsp] Junos OSPF Inter-Area Routes !
Dear All Recently I was working on a scenario in OSPF for checking the use of Backbone Area 0 for Inter-Area communication and I was surprised to see that 2 Non-Backbone areas were able to exchange inter-area routes without any Area 0 configured. Well the same thing did not work in Cisco which was the expected behavior per documentations. Topology was simple R1-Area3-R2-Area2-R1 Can anyone help to understand the above behavior in Junos. -- Regards Varma ___ juniper-nsp mailing list juniper-nsp@puck.nether.net https://puck.nether.net/mailman/listinfo/juniper-nsp
