Vlsm

1.1 VLSM
1.1.1 Name routing protocols that support VLSM OSPF, RIP v2, EIGRP, IS-IS
1.1.1 What does VLSM allow organisations to do? Use more than 1 subnetmask within an organisation
1.1.1 What is another name for VLSM Subnet a subnet
1.1.1. Why is VLSM necessary? Running out of IP v4 addresses
1.1.2 What is “subnet zero”? The first block of addresses in a subnet where the subnet bits are zero
1.1.2 Which IOS command relates to subnet zero? What does it do? ip subnet-zero
It lets you choose to use subnet zero or not (‘no’ in front of the command)
1.1.2 What change happened with IOS Version 12.0? Subnet zero enabled by default
1.1.3 Why is it sensible to use a 30 bit mask on point to point links? Only 2 addresses needed and only 2 available with this subnet mask
1.1.4 Name “classful” routing protocols that cannot support VLSM? IGRP, EGP, RIP v1
1.1.4 Define “classful” Protocols that follow ip address class rules
1.1.5 What is route aggregation? Only one routing table entry needed for multiple network addresses
1.1.5 Why was route aggregation necessary in the mid-1990’s? There would have been too many different networks and routes – routers would not have been able to deal with these complex routing tables
1.1.5 What information is sent by classless routing protocols such as OSPF or EIGRP during routing updates? 32 bit address and subnet mask
1.1.5 Explain the routing rule that gets around the problem of having to tell other routers about all the subnets connected to it. Summarise all the routes with 1 aggregate route
1.2 RIP Version 2
1.2.1 What are the key characteristics of RIP v1 Distance vector, broadcasts updates to neighbours, 30 second update interval, metric is hop count, 15 is maximum hop count.
1.2.1 Why is RIP v1 popular? Nearly all routers support it. Universally compatible.
1.2.1 What are the limitations of RIP v1? Does not send subnet mask information, broadcasts updates on 255.255.255.255, does not support authentication, does...