Confused need help

paul325i

Hey guys i'd like some help in narrowing down a question i'm thinking of, i can roughly remember that it related to either routers or switches all having the same ID, and to elect one what would happen.

Not entirely sure what this relates to but would they all keep using the same ID or would they use for example the ip address of one of their interfaces to decide until one was set differently to the others.

I know this is really vague but anybody have any suggestions as to what it might be regarding.

Thanks in advance.

knownasthatguy

i think you already know you need to provide more information, but let me give it a whack. The only ID i know of for a router pertains to OSPF where if you have a loopback, the LB will take over as the routers ID for DR and BDR elections. For switches, you might be thinking of the root bridge determination of which is not a choice. You also might be thinking of designated ports and port ID's for switch port roles. You can infact change the port ID on some switches which will change the ports role, blocked or desingated, but this is used for STP purposes.

Its been a while since ive done come campus networking, so if im wrong, give me a heads up

paul325i

I think it was the OSPF election process as you have said, Where router ID's are the same what interface will it use as an ID.

Also another similar one was if there is no loopback set, which interface would the router use as one?

I know i'm being vague, but thank you for helping. I'm looking to retake it this week.

knownasthatguy

i do believe that the interface does not matter, its the highest ip on the router that becomes the routers ID. the only interfaces that are concerned with the election process is the ethernet ports, not the WAN links.