RIP works at which layer of OSI model

Answered Question
May 7th, 2008

Hi


Does RIP work at layer 3 of OSI model or a higher layer? Because I saw in a book it says that RIPng uses UDP port number 521. If RIP uses a UDP port number, then it has to work at a higher layer, doesn't it?


Please someone clarify this to me.


Thanks in advance!

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dezoconnor Thu, 05/08/2008 - 03:09

RIP comes under the Layer 3 (Network layer) of the OSI model.


Paragraph taken from Cisco document:


"Routing protocols are network layer protocols that are responsible for exchanging information between routers so that the routers can select the proper path for network traffic."


http://www.cisco.com/en/US/docs/internetworking/technology/handbook/Intro-to-Internet.html#wp1020694


HTH

omal Thu, 05/08/2008 - 03:30

Hi


I totally agree with you. But I saw in a CCNA book that says RIPng uses UDP port number 521.


It is very confusing. I don't know what does it mean by that statement in that book.

omal Thu, 05/08/2008 - 03:37

Hi Michael


What you are saying is true about telnet. That is because telnet is a layer 7 protocol. Therefore it can use TCP at layer 4. But RIP is suppose to be a layer 3 protocol. So it can't have a layer 4 protocol.



omal Thu, 05/08/2008 - 04:23

Hi


The following is an output of a router. Even this output says that RIPng is using port number 521. Port numbers are assigned at session layer, which is layer5. So how does RIP uses a port number if it is a layer 3 protocol?




#show ipv6 rip


RIP process “1”, port 521, multicast-group FF02::9, pid 60


Administrative distance is 120. Maximum paths is 16


Updates every 30 seconds, expire after 180


Holddown lasts 0 seconds, garbage collect after 120


Split horizon is on; poison reverse is off


Default routes are not generated


Periodic updates 44, trigger updates 19


omal Thu, 05/08/2008 - 05:03

Hi Michael


That's cool.


Thank you so much for the clarification.


Warm regards!!!!!

viyuan700 Fri, 05/09/2008 - 18:53

Hope this will help u some more


Architecturally, RIP is a layer management protocol for what is called the Internetwork Layer in the Internet protocol suite or the Network Layer in the OSI Reference Model. While it is carried in end-to-end (IPS) or transport layer (OSI) packets, using port number 520 in the User Datagram Protocol (UDP), as a routing protocol, it belongs to the network layer, not the layer that moves its packets

omal Fri, 05/09/2008 - 20:03

Hi


Yes, it certainly helps. Thanks a lot for the post. It was short n sweet.


Warm regards!!!!!

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