Routing Protocols - exchange between routers NOT hosts and routers

Subnetting -

• Know the whole number subnetting

• Know for example if you /24 subnet and want to split it in half what is the new CIDR be = /25

• Want to make it twice as big = /23

• Number after the slash represents the number of the bits belonging to the network portion, portion that's not available to change

• Know how many ip addresses are in the whole number subnets - roughly don't need to know exact

  • Need a subnet for 11,000 ip addresses

    • Know what will fit in it /8 way too big /26 way too small. /17 would make much more sense

Checksum

• Only for the header in IPv4 or IPv6, not like the checksum in TCP or UDP

• Has to be recalculated by every router, needs to be recalculated for the new header

32 bits in IPv4 address

128 bits in IPv6 address

Classful addressing - inefficient, resulted in large institutions getting tens of millions of ip address

Classless addressing - Allows variable length subnet masks, can take a /24 and assign it to a department -> then can be split up even further

Know the private IPv4 Address ranges don't need to know IPv6 ranges

• Lecture 8

  • A private, B private, C private row

  • 172.200 outside of the private IP ranges

    • Know roughly the ranges will ask something obvious -

Know the local hosts - IP address that the computer will use to talk to itself

APIPA -

Subnetting - divi

CIDR notation - how you tell how an IP address was subnetted - what size subnet is it part of

ICMP - Error reporting message, troubleshooting and diagnostics activites

PING how you tell if something is up

Traceroute - ICMP utility you use how to plot the path

VLSM - allows for different sized subnets, variable length subnet masks

Know IPv6, public ip address are called global unicasts

Routing decisions - first prioirity length of the subnet mask match; how many other ip addresses exist in that network along with the desitation address

• If there is a tie there - then goes to the metric value- > picks the LOWER of the metrics

Know some of the ping option

• -t continuous

• -l change the size

  • More on the slides

Routers have a default gateway option - if there are no matches in the routing table - uses the default gateway -> leads to another router that’s larger or similar size

TTL values - Do not reach zero if you are going to a valid network -> TTL value up to 255, 128 more common

Remember Network Topologies

• Point-to-point networks - one computer directly connected to another computer

  • Packets in a p-t-p network are all gonna take the same network

Be able to spot a IPv6 address - know what it looks likes

MAC addresses - 48 bit values, don't get mac address and IPv6 address confused

Know how Network Address Translation works

Understand DHCP and why/how you would want to use it

Undertstand benefitis of IPv4

• Human readbalility

• Legacy

• More

Understand benefits IPv6

Concept of Fragmentation - messages and segments from the upper layers are frequently fragmented, not a problem as it happens at the sending device and not a device in the middle of the network

Network Address Translation - How we can continue using IPv4