Chapter 21 Exercises. A router forwards packets between networks. (Given a destination host address, it must be able to figure out which network that machine is on.). Big Question A ddresses have to be assigned to hosts based on the network they are on. How can that be done?. Exercise.
(Given a destination host address, it must be able to figure out which network that machine is on.)
Addresses have to be assigned to hosts based on the network they are on. How can that be done?
You are the CIO of a company and get 10000 addresses total (numbered 0 to 9999) and have 10 networks each managed by a different administrator, and you want each network administrator to be able to assign addresses independently. How do you allocated addresses?
(Remember how routers work: move packets based on network addresses, not host addresses.)
What if you had 100 networks in your company? What scheme would you use? Can you answer the questions from the previous slide?
What if you had 12 networks in your company? What scheme would you use?
Your company is connected to the Internet via one router, so other computers can communicate with hosts in your network. What do the routers in the Internet need to know to send packets to your company’s networks?
BUT: somehow routers in your network have to be configured to know which part of the address is _________ _______ and ______ ________.
Come up with a scheme to indicate this.
Question: does a router need this “indicator” to identify a host?
(Why does IP use binary addressing instead of decimal?)
Suppose you have 1 byte IP addresses. How many total IP addresses in the world?
Suppose you have 4 (sub) networks. How to allocate addresses?
Can you compute the network from the host IP address?
What is the subnet mask?
What are the formulas for computing max hosts supported on a subnet and max # of networks?
How many bytes is that?
How many total addresses (theoretically)?
How is a 32-bit address written?
What are common divisions between network part and host part?
Why was it invented?
How many class A networks? B? C? (What are the “implied” masks for these networks?)
What if you needed 500 addresses? What class address would you get? How many wasted addresses?
What changed from classful addressing?
What must routers know now in order to forward packets correctly?
What kind of address is this? (host? network? limited bcast? directed bcast?)