Transcript CSEE W4140 Networking Laboratory

CSEE W4140
Networking Laboratory
Lecture 12: Review
Jong Yul Kim
04.22.2009
Annoucements
 Visit to TelioSonera’s NY POP
 Meet in front of Broadway and 116th st
main gate at starting time.
 Wednesday group: 1 pm
 Friday group: 10 am
 Can you join the Friday group?
ICANN
 Internet Corporation for Assigned Names and Numbers
IANA
 Is run by ICANN
 Provides global coordination of




Domain names (manages root)
IP addresses
AS numbers
Protocol assignments
Registry Listings from ICANN
TLD
Introduced
Sponsored/
Unsponsored
.com
1985
Unsponsored
Unrestricted (but
intended for
commercial
registrants)
VeriSign, Inc.
Registry Customer
Service
VeriSign Naming
Services
21345 Ridgetop Circle
Dulles, Virginia 20166
United States
Tel : +1 703 925-6999
Fax: +1 703 421-5828
http://www.verisigngrs.com
.net
1985
Unsponsored
Unrestricted (but
intended for
network
providers, etc.)
VeriSign, Inc.
Registry Customer
Service
VeriSign Naming Services
21345 Ridgetop Circle
Dulles, Virginia 20166
United States
Tel: +1 703 925-6999
Fax: +1 703 421-5828
http://www.verisigngrs.com
.edu
1985
Sponsored
United States
educational
institutions
EDUCAUSE
Becky Granger
EDUCAUSE
4772 Walnut Street, Suite
206
Boulder, Colorado 80301
United States
Tel: +1-303-939-0334
Fax: +1-303-440-0461
http://www.educause.edu/
edudomain
Purpose
Sponsor/
Operator
Contact
Regional Internet Registries
(RIRs)
 Registration and management of IP address is done
by Regional Internet Registries (RIRs)
 Where do RIRs get their addresses from: IANA
maintains a high-level registry that distributes large
blocks to RIRs
 RIR are administer allocation of:
 IPv4 address blocks
 IPv6 address blocks
 Autonomous system (AS) numbers
Regional Internet Registries
(RIRs)
Tiered hierarchy of ISPs
Tier-1 ISPs
 Tier-1 ISPs form the
backbone of the
Internet
 Directly connected to
each other for free:
this is called peering.
 Tier-2 ISPs and other
networks connect to
them for a fee: this is
called transit.
 International presence
Name
AS #
AT&T
7018
Global Crossing
3549
Level 3
Communications
3356
NTT Communications
2914
Qwest
209
Sprint
1239
Tata Communications
6453
Verizon Business
701
SAVVIS
3561
TeliaSonera IC
1299
What happens if Tier-1 ISPs fight
each other?
 Excerpts from “Sprint, Cogent in Peering
Feud” by Karl Bode as published in
dslreports.com.
 “A high profile dispute with Swedish telecom
operator Telia in March cut off access to vast
swaths of Europe.”
 “The latest fight came last night, when Cogent
announced that Sprint pulled the plug on their
connection with the Cogent network, impacting
a significant amount of both URLs and
broadband customers.”
Point-of-Presence (POP)
 A location where ISPs interconnect
with each other.
 Usually houses a group of routers and
switches that are shared among the
ISPs.
 Also known as Internet Exchange
Points (IXP)
Routing Protocols
 BGP for interdomain routing
 RIP and OSPF for intradomain routing
 RIP is a distance vector protocol.
 Count-to-infinity is a problem.
 There are ways to deal with the problem.
 OSPF is a link state protocol.
 All routers have the same routing information.
 Unless they are divided into two-level hierarchy
called areas.
LAN and switches
 In setting up a LAN, you can use
routers, hubs, and switches.
 Routers vs. switches
 Hubs vs. switches
 Switches have nice properties.
 Plug-and-play through learning algorithm
 Spanning Tree Protocol to avoid loops
IP addressing and subnets
 IP addresses
 have two parts: prefix and host. (CIDR notation:
10.0.2.0/24)
 Prefixes are used by routers to forward packets
to the correct destination
 Subnets
 Are divided by routers and hosts.
 Every machine in a subnet uses the same prefix.
 What happens if a machine’s netmask is
different from the subnet’s prefix?
ARP
 ARP is used to find the MAC address of the
machine that uses a particular IP address.
 ARP is used within a subnet.
 Unless a router uses proxy ARP to forward ARP
requests to another subnet.
 There are many other uses of ARP.
 IP conflict detection
 RARP for IP address configuration
NAT and DHCP
 NAT
 is an outcome of the shortage of IPv4 addresses.
 But they can be used in many different
applications, e.g. support migration between
service providers.
 NAT can be problematic for some
applications.
 DHCP is used to configure hosts within a
subnet automatically.
 Relays can be used to traverse subnets.
SNMP
 SNMP is used for network
management.
 The information objects are
structured as a tree. (OID reflects the
tree structure.)
 Four parts: MIBs, SMI, the protocol,
and security.
Homework
 No prelabs due this Friday
 Lab report 9 due next week by the
normal dates