Chapter 8 - Routing Flashcards
Define Router
Any piece of hardware or software that forwards packets based on their destination IP address
How does a router determine the destination
By reading the IP addresses of the packets. Destination doesn’t matter
Define Gateway
The IP address for the next hop router; where the packet should go next.
What does the router do if there is more than one route
Picks the best one. the router with the lowest metric wins
In terms of routing, what does zero mean
Anything, like a wildcard
Why is this route important and translate the route into english: Destination: 0.0.0.0 Subnet Mask: 0.0.0.0 Gateway: 76.30.4.1 Interface: WAN
Any destination with any subnet mask forward it to 76.30.4.1 using my WAN port. This tells the router exactly what to do with every incoming packet unless another line says otherwise
Translate this route into english: Destination: 10.12.14.0 Subnet Mask: 255.255.255.0 Gateway: 0.0.0.0 Interface: LAN
Any packet for the 10.12.14.0/24 Network ID, don’t use a gateway, just ARP is on the LAN interface to get the MAC address and send to recipient
What is the Tier One Backbone
Where you’ll find the routers that make the main connections of the internet
Define Metric
a relative value that defines the ‘cost’ of using this route
What is a general statement to describe the internet
A Whole bunch of big powerful routers connected to lots of other big powerful routers
What is a loopback address
As long as it starts with 127 it will always go to 127.0.0.1
jWhat is the difference between a directed broadcast and a full broadcast
Directed broadcast goes only to the targeted subnet rather than the full broadcast domain
Define NAT
Network Address Translation hides the IP addresses of computers on a LAN but still enable those computers to communicate with the broader internet. The router replaces the source IP with its outside interface address
What is basic NAT
Translating the private or internal IP address to a global IP address on a one to one basis.
Define Port Address Translation (Pat)
Uses port numbers to map traffic from specific machines in the network
Define Static NAT
Maps a single routable IP address to a single machine
Define Dynamic NAT
Enables computers to share a pool of routable IP addresses that number fewer than the computer. Dynamic NAT is also called ‘Pooled NAT’
What is a ‘hop’ defined as
Each time a packet goes through a router
What are the three distinct groups of routing protocols
Distance Vector
Link State
Hybrid
What is the criteria for determining a Metric
Hop count - one way count
Bandwidth
Latency - the issue that distance causes
Cost - route through lower bandwidth has more cost than higher bandwidth
Define Maximum Transmission Unit
Maximum Transmission Unit determines the largest frame a particular technology can handle
Define Fragmentation
When a IP packet is too big for a technology the packet is broken into pieces. This causes slowdowns on the network
Define Shortest Path Bridging
Shortest Path Bridging is a routing metric standard to provide true shortest-path forwarding within mesh topology. Provides fast convergence and improved usage of mesh networks with multiple equal cost paths.
Define Distance Vector
calculate the total cost to get to a particular network ID and compare that cost to the total cost of all the other routes. Routers using this transfer their entire routing table to other routers in WAN
