Network Implementation (Chapter 2)

Question 1

Routing

Answer 1

Is the movement of packets between network based on Layer 3 headers, performed by routers. They pass the packet along (hop) until the packet reaches it’s destination.

Question 2

Router golden rule

Answer 2

All routers must know what to do with packets, either by having the packets destination in it’s routing table or by having a default route to pass the packet to

Question 3

Default Route

Answer 3

Is route that a router sends packets to when there are no other available routes

Question 4

2nd Golden Rule of Routing

Answer 4

The router must be able to choose which interface to send the packet out of. Each router interface must belong to a different network

Question 5

Static Routing

Answer 5

Is when routes are manually entered into the routing table. All route must be entered into all routing tables or packets will be lost. It allows a router to know which route to take to reach a network

Question 6

Dynamic Routing

Answer 6

Routers use protocol that are used to inform routers of routes upstream.

Question 7

Routing Protocols

Answer 7

Distance Vector
- routers on fixed intervals would broadcast their route tables which would be used by other routes to update their route tables
Link State
- would only broadcast route table updates when a link changes state
- Routing Information Protocol (RIP)
Hybrid
- uses the best of both link State and distance Vector
- Enhanced Interior Gateway Routing Protocol (EIGRP)
Path Vector
- determines the best path by maintaining route path information and policies
- Border Gateway Protocol (BGP)

Question 8

Interior/Exterior Gateway Protocols

Answer 8

Interior Gateway Protocols
- are protocols used within a private network
- RIP, OSPF, EIGRP, iBGP
Exterior Gateway Protocols
- used between ISP on the internet
- BGP

Question 9

Border Gateway Protocol

Answer 9

Is an exterior router protocol that allows a router to count an autonomous system as a single hop
- Exterior
- TCP 179
- unicast
- slow convergence
- administrative distance 20
- no load balancing
- complex to set up

Question 10

Enhanced Interior Gateway Routing Protocol (EIGRP)

Answer 10

Is a protocol used by routers that ensures that each router on an interior networks maintains a topology table of the entire network
- interior
- Protocol ID 88
- administrative distance 90
- has loads balancing
- easy to set up

Question 11

Autonomous System

Answer 11

An Identifiable number assigned to a network that is under a single administrative that controls 50000 routes within their network

Question 12

EIGRG Successor/Feasible Successor

Answer 12

Successor
- is the best route to a destination
Feasible Successor
- is a backup route to the same destination

Question 13

OSPF

Answer 13

Is a protocol for routers that divides a network into areas into a Hierarchical structure.
- Interior
- Protocol ID 89
- multicast
- fast convergence
- administrative distance 110
- No load balancing
- complex to setup

Question 14

Router forwarding decisions

Answer 14

Routers make routing decision based on
- longest prefix match (route with the longest CIDR mask)
- administrative distance
- Routing Protocol Metric

Question 15

Prefix Length

Answer 15

Prefix is the length of the subnet mask in the router (largest CIDR number).
A longer prefix is more specific to where the destination is.

Question 16

Prefix Length

Answer 16

First criteria for route selection
Prefix is the length of the subnet mask in the router (largest CIDR number).
A longer prefix is more specific to where the destination is.

Question 17

Administrative Distance

Answer 17

2 criteria for route selection
Is the believability of a route source which could be Directly connected, statically entered or a routing protocol. Each source has an administrative distance.

Question 18

Routing Protocols Metric

Answer 18

Third criteria for route selection
Is the cost of a particular route compared with other routes with the same adminstrative distance

Question 19

Network Address Translation

Answer 19

Performed by routers and firewalls that translates the internal private IP address into a public IP address to access the internet.
- Packets IP are temporarily changed to the public IP

Question 20

Port Address Translation

Answer 20

Performed by routers when multiple devices are attempting to access the internet, it translates their private IP address into the same Public IP address but the router maintains the devices original source port.

Question 21

First Hop Redundancy Protocol (FHRP)

Answer 21

Is when multiple routers act as a single default gateway for all host on a network.
- all routers will share a Virtual IP and Virtual MAC that all host will send their traffic to

Question 22

Subinterfaces

Answer 22

Are logical interface created on a routers physical interface that allows multiple VLAN to use the logical interface as it’s default Gateway and subnet