Chapter 7 - IP addressing Flashcards
What IP address denotes the default address.
0.0.0.0
What are Anycast addresses?
These are the addresses that we can assign to multiple hosts at the same time, though, a packet destined for such a anycast address is always delivered to a single host.
So basically whichever is the nearest host with this anycast address, gets that packet.
What are the private classes in IPv4?
Class A - 10.0.0.0 - 10.255.255.255
Class B - 172.16.0.0 - 172.31.255.255
Class C - 192.168.0.0 - 192.168.255.255
What is the first octet of different classes?
Class A - 1 - 126
Class B -> 128 - 191
Class C - 192 - 223
class D (Multicast) -> 224 - 239
Class E - 240 - 255
What is the loop back address in IPv6?
0::1
What hex numbers does Global unicast IPv6 address start with?
2000:: /3
What hex numbers does Link Local IPv6 address start with?
FE80:: /10
What hex numbers does unique local unicast addresses IPv6 address start with?
FC00:: /7
What hex numbers does multicast IPv6 address start with?
FF00:: /8
What 2002:: /16 used for in IPv6?
It is used with 6-4 tunneling.
How an IPv4 address would be denotes in IPv6?
0::FFFF:IP address
How EUI-64 (Stateless autoconfiguration works)?
Hosts get prefix - 64 bits, from the router.
Rest of the 64 bits are derived from MAC address of the host which is 48 bits long.
So a pad which is FFFE, is added in the middle of MAC address and also 7 bit of the MAC address is inverted.
What is IP dual stacking?
Dual stacking means hosts can support both the IPv4 and IPv6 communication at the same time.
What happens if the 6-4 tunnel goes through a router that has NAT enabled?
Tunnel gets broken.
What is the administrative distance of most common routing protocols?
EIGRP - 90, IGRP - 100, RIP - 120, OSPF - 110, IS-IS - 115, External BGP - 20, Static route - 1, Connected route - 0
Give me one difference between Distance vector routing protocol and Link state routing protocol?
Distance vector routing protocol share their whole routing table in its routing updates.
Link State routing protocols share only updates when some topology change occurs. They share the state of their links with the other routers.
Define RIP2
It uses hop count as its metric and has a maximum hop count of 15.
RIP2 supports VLSM and auto summarization.
It sends its routing updates to a multicast address 224.0.0.9 after every 30 seconds.
EIGRP - Enhanced interior gateway routing protocol - define it?
It is a hybrid protocol. It uses the concept of Autonomous systems. It creates 3 kind of tables - neighbor table, topology table, routing table.
It only sends updates out its interfaces when some topology changes occurs.
It uses DUAL (Diffusion update algorithim) to find the best route.
What key things does it look at to find the best path - it metric is bandwidth, delay of line/ link. (It might also use MTU, medium reliability, load to find the best path as its optional parameters).
Note - it is easy to configure in an internetwork as compared to other protocols like OSPF
What is route redistribution?
It is an protocol/ algorithim that translates the routes learned via one routing protocol (For example - learned from RIP2 ) to EIGRP routes.
Define Border Gateway protocol.
It is a path vector protocol. So during its routing updates, it sends the AS number of routers and the path vector information (hope by hop information of every device that a packet will travel through to reach the destination).
It also makes stateless routing and summarization possible. Which makes the routing tables to be smaller.
Define OSPF.
Open Shortest Path First - It uses DIJKSTRA algorithim.
It also makes use of 3 tables.
It breaks down the big network into smaller areas. So there is a Area 0 to which every other area connects to.
Router that connects the area 0 to other areas in OSPF is called AREA BORDER ROUTER.
It supports both IPv4 and IPv6 networks but it keeps a sperate database for both of them.
It is more complex to maintain. It supports manual summarization.
What is First Hop Redundancy Protocol?
this is a protocol with which we can configure multiple routers to be the default gateway for hosts in a network for redundancy purposes.
Ex of this protocol - HSRP, VRRP
Define Hot Standby Redundancy Protocol.
HSRP allows us to configure one or more routers into a standby group that shares an IP address and MAC address and shares a default gateway.
HSRP.
It makes an HSRP group that consists of following routers - One Active router, one or more standby routers and virtual router.
These routers in this HSRP group communicates with each other using various timers using Multicast addresses.
How do we get a virtual MAC address in HSRP?
So first 24 bits are the organizationally unique identifier. Next 16 bits in the address tell us that the MAC address is a well known HSRP MAC address. Finally the last 8 bits are the hexadecimal representation of HSRP number.
