NSWI141: Introduction to Networking

Test

Dates of exams are provided in the Student Information System where the registration is being made as well. You can reserve a place before earning two points for the web part, but you must already have points assigned in Recodex before you start your test.

Due dates take place at the end of the Winter semester and during the examination period. Also, there will be some more exams in the Summer semester examination period.

The exam is in form of a quiz, you can look at the introduction, list of questions and a task example (here). For this question, I have deliberately chosen BGP which is a peripheral topic and there are no questions on it in the actual test.

Which of the following statements about BGP (Border Gateway Protocol) is true?

• BGP is an example of IGP protocols.

  False. BGP is an external routing protocol (EGP).

• BGP is an external routing protocol, it is used for routing from internal network (LAN) to internet.

  The first part is OK, but the explanation is wrong - "external" means that routing outside our autonomous system (AS), not the LAN. If our network is not on an AS perimeter, our router uses internal routing protocols.

• Using BGP a router mutually exchanges information with all other computers in the network.

  A router only exchanges information with other routers (which we could call "computers", there is no catch), but computers other than routers can at most monitor data exchange using BGP (one-way).

• Using BGP, a router interchanges information with all other routers in the network.

  Even this sentence is not true. The router interchanges data only with external routers, not with internal ones.

• When a packet for an unknown network arrives to a BGP router, the router uses BGP queries to learn the proper route to send the packet.

  No. Although the router uses BGP for getting the information for proper routing, the process is continuous. When a packet arrives, there is no work for the BGP, the router just searches through the routing table according to the routing algorithm like any other network node.

• BGP router sends his BGP neighbors information about networks in his AS (addresses, netmasks, number of hosts).

  Almost correct, but number of hosts has no relevance for routing and no such data is being sent.

• If the BGP router has the correct configuration, it is guaranteed that packets going from the own LAN to the Internet will be delivered.

  Even a correctly configured router does not GUARANTEE that a cable to the Internet will not be broken by a bulldozer.

• If an AS (autonomous system) has a single ISP, it uses the ISP as a default route and it needs no other information from the BGP protocol. Thus, the TCP packets of the BGP connection are sent only in one direction (outward).

  This answer should be rejected without any knowledge about BGP. In the TCP, the packets must be sent in both directions, otherwise it does not work.

• No answer is correct.

  Yes, this answer is correct.

FAQ

• What literature should I study?

  The essential knowledge is covered by slides. If you know and understand the slides, you should pass the exam. And if you don't remember or understand some fact, you should find sufficient explanation on the net.

• Are numbers of ports or RFC documents subject of examination?

  PLook at the sample question. Of course, the HTTP port number belongs to essential knowledge from the viewpoint of this course, but this is true for only a few basic numbers. And RFC numbers are not this case at all.

Use of own personal computer or communication devices (for a purpose other than working with the test application and our supervising of it) is not permitted.

The results will be entered into SIS as soon as the tests are evaluated.

You have three attempts to pass.