cancel
Showing results for 
Search instead for 
Did you mean: 
cancel
Announcements
145
Views
0
Helpful
3
Replies
Highlighted
Beginner

Routing Protocol information

What information is shared between ospf and rip routers

Everyone's tags (1)
1 ACCEPTED SOLUTION

Accepted Solutions
VIP Expert

Re: Routing Protocol information

If each router is running either just OSPF or RIP, they cannot share information. However, if one of those routers is running both IGPs, it can, as noted by Jon, redistribute route information from one IGP to the other. Such redistribution can be one way or both ways, and might contain all the information known to one IGP sent to the other IGP or just a subset of that information. When passing information between IGPs, you may run into "translation" issues, as different IGPs often don't carry exactly the same attributes. For example, RIP has "distance" to a destination based on router hops (contained by 4 bits) while OSPF has a sum of link costs to the destination (contained by 16 bits). Or, RIPv1 works with classful addresses while OSPF supports classless addresses. (Also when doing two way redistribution, if there's more than one redistribution router, you generally want to avoid feeding back the route information received from the other IGP back to it. I.e. you need to be extra careful what's shared.)

 

[edit]

Oh, and if you do have more than one IGP on the same router, although, again by default, the two IGPs don't share any information, the router, itself, generally builds a route table using information from all the active IGPs on it.  If there's overlapping route information, the router has "rules" on which IGP is considered to have "better" information.  By default, OSPF route information is considered better than RIP route information, to the same destination.

3 REPLIES 3
Hall of Fame Guru

Re: Routing Protocol information

 

Not sure what you are asking. 

 

A router running OSPF exchanges no information with a router running RIP unless of course you are doing some sort of redistribution, 

 

Jon

VIP Expert

Re: Routing Protocol information

If each router is running either just OSPF or RIP, they cannot share information. However, if one of those routers is running both IGPs, it can, as noted by Jon, redistribute route information from one IGP to the other. Such redistribution can be one way or both ways, and might contain all the information known to one IGP sent to the other IGP or just a subset of that information. When passing information between IGPs, you may run into "translation" issues, as different IGPs often don't carry exactly the same attributes. For example, RIP has "distance" to a destination based on router hops (contained by 4 bits) while OSPF has a sum of link costs to the destination (contained by 16 bits). Or, RIPv1 works with classful addresses while OSPF supports classless addresses. (Also when doing two way redistribution, if there's more than one redistribution router, you generally want to avoid feeding back the route information received from the other IGP back to it. I.e. you need to be extra careful what's shared.)

 

[edit]

Oh, and if you do have more than one IGP on the same router, although, again by default, the two IGPs don't share any information, the router, itself, generally builds a route table using information from all the active IGPs on it.  If there's overlapping route information, the router has "rules" on which IGP is considered to have "better" information.  By default, OSPF route information is considered better than RIP route information, to the same destination.

VIP Advocate

Re: Routing Protocol information

Hi,

As RIP and OSPF are both different routing protocol and their behaviour is also different. By default, both will not share any such kind of information with each other. 

There is a mechanism which is called redistribution will use for import one routing protocol's routes into another protocol as an import from OSPF and Export into RIP. But keep in mind that this is not an actual import and export between routing protocols. It will share only those routes which are installed in the routing table by the router where you did redistribution. This may one way or both ways means OSPF to RIP or OSPF to RP and RIP to OSPF.

During the redistribution, the importer routing protocol will assign some short of COST/Metric and it completely depends on the importer routing protocol. 

 

Regards,

Deepak Kumar

 

Regards,
Deepak Kumar,
Don't forget to vote and accept the solution If this comment will make help you!
CreatePlease to create content
Content for Community-Ad
July's Community Spotlight Awards