What is an
autonomous system?
Internet is so large that no one routing protocol
can handle the task of updating the routing tables of all routers. Internet is
divided into autonomous systems.
An
autonomous system is a group of networks and routers under the authority of a
single administration.
Routing
inside an autonomous system is referred to as intra-domain routing. Routing
between autonomous systems is referred to as inter-domain routing.
What is
interdomain routing?
The interdomain routing involves AS sharing their
reachability information with each other AS.
The goal of interdomain routing is reachability
and not optimality.
The
two major interdomain routing protocols are Exterior Gateway Protocol (EGP)
and Border Gateway Protocol (BGP).
What are the problems
in interdomain routing?
An internet backbone must be able to route packets
to any destination, i.e., there should be a match in the routing/forwarding
table.
Each
AS has its own intradomain routing protocols and chooses the metric assigns to
path. This varies from one AS to another.
Autonomous
systems may not trust each other.
Write short
notes on BGP.
Border Gateway Protocol (BGP) is an inter-domain
routing protocol using path vector routing
Traffic
on the internet can be classified into two types:
o
local traffic
that starts/ends on nodes within an AS
o
transit traffic
that passes through an AS AS can be classified into three types
o
Stub AS has
only a single connection to one other AS. This AS can carry local traffic
only, such as Small corporation.
o
Multihomed AS has
connections to more than one other AS but refuses to carry transit
traffic, such as Large corporation.
o
Transit AS has
connections to more than one other AS and is designed to carry both
transit and local traffic, such as the backbone providers
Each
AS selects one of its nodes to be the BGP speaker.
Speaker
node creates a routing table for that AS and advertises it to other BGP
speakers in the neighboring ASs.
State the
drawbacks of IPv4?
Despite all short-term solutions, such as
subnetting, classless addressing, and NAT, address depletion is still a
long-term problem in the Internet.
The
Internet must accommodate real-time audio and video transmission that requires
minimum delay strategies and reservation of resources, which are not provided
in IPv4.
The
Internet must provide encryption and authentication of data for some
applications. No encryption or authentication is provided by IPv4.
