For anyone interested, I labbed out the OSPF interface selection process where two OSPF processes are configured to advertise out a single interface.
Basically, the first OSPF process in the router's config has priority over the interface. The actual numerical value of the OSPF process has zero influence over "who gets the interface." If you issue "show ip ospf int," the interface will show up only once and assigned to the first OSPF process in the router's config. However, if you issue "sho ip protocols," the output shows that the network assigned to the interface is being routed for both processes. This output is misleading and incorrect. If you remove the first OSPF process (the one actively advertising out the interface), the remaining OSPF process will not "grab" the interface until the router is rebooted or "clear ip ospf processes" is issued. Hope this helps.... -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Marko Milivojevic Sent: Friday, November 27, 2009 6:48 AM To: Joe Astorino Cc: [email protected] Subject: Re: [OSL | CCIE_RS] Clarification on RS_Vol2_DSG_v11.o_Lab1 - Task4-1 & Task 5-1 On Thu, Nov 26, 2009 at 21:03, Joe Astorino <[email protected]> wrote: > Like Marko said, you can have an interface being advertised and > participating in multiple routing protocols. Which one gets put into > the RIB on the other side will depend on AD assuming there is no other > filtering going on. I think this scenario needs to be explored from multi access point of view. I find it unlikely that one will run multiple routing protocols on p-t-p links, except during migration. However, it could happen that on certain shared segments (Ethernet, Frame Relay, ATM), some routers speak different protocols. What's important is that this is possible. -- Marko Milivojevic - CCIE #18427 Senior Technical Instructor - IPexpert Mailto: [email protected] Telephone: +1.810.326.1444 Live Assistance, Please visit: http://www.ipexpert.com/chat eFax: +1.810.454.0130 _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com _______________________________________________ For more information regarding industry leading CCIE Lab training, please visit www.ipexpert.com
