3 IP Addressing and Routing Free Online FlashCards

How long is an IPv4 address, and how is it conventionally written?

IPv4 addresses are 32 bits long and are conventionally written as four decimal octets, such as 192.0.2.25.

What does the /24 prefix mean in 192.0.2.25/24?

A /24 prefix means 24 leading bits identify the network and 8 bits remain for hosts; its subnet mask is 255.255.255.0.

Which IPv4 ranges are reserved for private networks?

The private IPv4 ranges are 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16. They are not globally unique public addresses; NAT is commonly used for public Internet access.

How can an IPv6 address be shortened when written?

IPv6 addresses use 128 bits, written as eight hexadecimal groups separated by colons. Leading zeros may be omitted, and one continuous run of zero groups may be written as :: once per address.

Which address types does IPv6 use, and which familiar type does it lack?

IPv6 supports unicast, multicast, and anycast addressing, but it has no broadcast addresses.

What does a /64 prefix identify in a typical IPv6 LAN?

A /64 is the common IPv6 LAN subnet size. Its prefix identifies the subnet, and the remaining bits identify an interface.

How many /26 subnets come from 192.168.10.0/24, and how many hosts can each conventionally support?

Changing 192.168.10.0/24 into /26 subnets borrows 2 bits, creating 2² = 4 subnets. Each has 64 addresses and conventionally supports 62 host addresses.

What is the /31 exception for IPv4 point-to-point links?

On a conventional IPv4 subnet, the subnet and broadcast addresses are typically unavailable for host assignment. The /31 point-to-point-link exception allows both addresses to serve as endpoints.

Why use variable-length subnet masking (VLSM)?

Variable-length subnet masking (VLSM) assigns subnets of different sizes according to need, helping conserve address space.

How does longest-prefix match choose a route?

A router chooses the matching route with the most network bits. For destination 10.0.2.1, 10.0.2.0/24 takes precedence over 10.0.0.0/16.

When does a router use a default route?

A default route, 0.0.0.0/0 for IPv4 or ::/0 for IPv6, matches destinations without a more-specific route and often points toward an upstream router.

What does a routing metric indicate, and what limits comparisons between protocols?

A metric measures route preference within a routing protocol. Metrics from different protocols are not necessarily comparable; some platforms use a separate administrative preference for routes to the same prefix.