Routing versus routed protocolsMany networking professionals don't really know what a routing protocol is or does. There are those who also couldn't tell you the difference between a routing protocol and a routed protocol. If you are working as a network engineer or preparing to take the CCNA, you need to understand the distinction between routing and routed protocols, as well as how these protocols function on the network.
Routing protocols distribute routing information throughout all routers on a network. By knowing about all other routers connected to the network, each router can determine the best path to use to deliver your traffic. Examples of routing protocol would be OSPF, RIP, EIGRP or BGP.
Routed protocols can be sent over a routed network. Today, with IP (think of TCP/IP) being the predominate protocol in use on the Internet and in most networks, we don't often think about routed versus unrouted protocols. That is because IP is a routed protocol. Meaning, IP is designed such that it can be routed over and through different networks. This is because the IP address is broken up into network and node (host) by the subnet mask. An example of a protocol that is not routed (unroutable) would be NetBIOS. It works great on a small local network (in your house) but wouldn't work well over a large network connected by dedicated network circuits or the Internet.
Routing quiz: prep for your CCNA!Are you preparing for the CCNA exam? Maybe you just want to test your knowledge of routing and routed protocols. This quiz will tell you if you are up to speed when it comes to TCP/IP protocols.
1. What routing protocol uses cost as its metric?
3. Which of these routing protocols would be used between Autonomous systems (Inter-AS)?
4. Which routing protocol has a default administrative distance of 110?
5. Which routing method is most trusted by a router?
6. What is the process of sending routes from one routing protocol to another routing protocol?
e. Source routing
7. Which command tells RIP to send hellos, out an interface, to find neighbors and to advertise routes?
8. You want to filter inbound routes from an OSPF neighbor. Which command do you use?
9. In BGP, OSPF and EIGRP, an internetwork under common administration is called what?
a. Routing system
b. Autonomous routing
c. Routing domain
d. Autonomous system
10. Which command do you use to prevent OSPF HELLO packets from going out of a configured interface?
a. no network
c. no advertise
11. In OSPF, every router must have communications back to what?
a. Area zero
b. The root
c. OSPF central
d. Area one
12. Which of these routing protocols would be unavailable on a non-Cisco router?
13. What type of OSPF router would connect an area that is not using OSPF?
14. A router receives two identical routes from different protocols. What route is put into the routing table?
a. The route with the most trusted AD
b. The best route
c. The OSPF route
d. Both routes
15. If RIP receives two similar routes to a network, which route is put into the routing table?
a. The route with the most trusted administrative distance
b. The most specific route
c. The RIP version 2 route
d. Both routes
1. C (OSPF)
2. B (BGP)
3. D (BGP)
4. B (OSPF)
5. C (Static)
6. A (Redistribution)
7. B (Network)
8. A (Distribute-list)
9. D (Autonomous system)
10. B (Passive)
11. A (Area zero)
12. C (EIGRP)
13. D (ASBR)
14. A (The route with the most trusted AD)
15. B (The most specific route)
About the author:
David Davis (CCIE #9369, CWNA, MCSE, CISSP, Linux+, CEH) has been in the IT industry for 15 years. Currently, he manages a group of systems/network administrators for a privately owned retail company and authors IT-related material in his spare time. He has written over fifty articles, eight practice tests and three video courses and has co-authored one book. His website is at www.happyrouter.com.
This was first published in June 2006