Download - 04 Mobile+Internet+Part+1
-
8/13/2019 04 Mobile+Internet+Part+1
1/15
Chapter 8, secs 8.1,8.2
Wireless LANs, 802.11, and WiFi
Part 2
Resources Folder in Sakai:
Protocols-reading.pdfIP-reading.pdf
Outline
Network Layer
Protocols and Internetworkin
IP version 4
Address Exhaustion
IP version 6
McNair, Sp13 EEL 4930: Wireless and Mobile Networks 2
-
8/13/2019 04 Mobile+Internet+Part+1
2/15
Network Layer
1. Manages Global Connections
b) Datagram and virtual circuit networks Routing
2. Manages Global addresses
(e.g., telephone number or IP address)
a) The IP Address
b) IP Address assignment
c) Address resolution
d) Address exhaustion / Making the IP Address Las
(subnets, supernets, network address translation)
3. Manages Global Packet Delivery
a) IP v4 or v6 Packets
b) Fragmentation and Reassembly
3
Protocols and Internetworking
Node D
IP addr:Router X
Node A
IP addr:
MAC addr:
Node B
IP addr:
MAC addr:
Node C
IP addr:
MAC addr:
Node E
IP addr:
MAC addr:
A a r:
4
-
8/13/2019 04 Mobile+Internet+Part+1
3/15
Internetworking:
Sending a Packet from Node A to Node E
Node D
IP addr:
MAC addr:Router X
Node A
IP addr:
MAC addr:Router Y
IP addr:
MAC addr:
Node C
IP addr:
MAC addr:
Node E
IP addr:
MAC addr:
Node A (Source) operation.Determine if destination
address is in the current
Router X operation.LAN headers are strippedIP address obtainedRouting decision is made.IPdata ram is ut in X.25
7
.
If destination is in a
different destinationnetwork, a router is chosen
(Router X).
Put IP datagram in MAC
frame and send to Router X.
packet and sent to Router Y.
Router Y operation.X.25 headers are strippedIP address obtainedRouting decision is made.IP datagram is put in MACframe and sent to Node E
8
-
8/13/2019 04 Mobile+Internet+Part+1
4/15
Address Resolution
1. The source must determine the IP address of the
.
2. The source must also determine the address that
should be used to send the packet.
a) Note: the address chosen will depend on whether the
destination is on the same LAN or is outside of the LAN
9
. .
Address Resolution
1. Find IP Address of Destination.
Source queries the domain name system (DNS)
to o ta n t e a ress o t e est nat on.
An application program on the source passes the
name of the destination (e.g., www.ufl.edu) as a
parameter to a DNS library procedure (the resolver).
The resolver sends the name to a local DNS server.
The DNS server looks u the name and returns the IP
10
address of the destination to the resolver, which
returns the IP address to the source.
-
8/13/2019 04 Mobile+Internet+Part+1
5/15
2a. Find MAC Address of Destination
Destination is in the same LAN.
Source broadcasts and ARP acket to the LANto determine destination address
ARP -- Address Resolution Protocol
ARP packet contains the destinations IP address.
Destination recognizes its own IP address in theARP packet
11
espon s w a pac e con a n ng e es na on sMAC address.
2b. Find MAC Address of Destination
Destination is outside of the LAN.
Source broadcasts and ARP packet to the LAN
o e erm ne es na on a ress ARP -- Address Resolution Protocol
ARP packet contains the destinations IP address.
Edge router recognizes that the IP address is
not on the LAN
12
Proxy ARP
Source maps the edge routes MAC address to the
destinations IP address.
-
8/13/2019 04 Mobile+Internet+Part+1
6/15
3. Find IP Address of the Source.
Reverse ARP (RARP) server
A server on the LAN.
Contains a table that maps the local MAC
addresses to their IP addresses.
RARP
13
own MAC address.
RARP server sends back the sources IP
address.
Address Resolution
Example
Node A
Node B
IP addr:
MAC addr:
Node C
IP addr:
MAC addr:
Node E
IP addr: 222.222.222.222
MAC addr:
Node D
IP addr:
MAC addr:Router X
MAC addr:
Router Y
14
-
8/13/2019 04 Mobile+Internet+Part+1
7/15
IP version 4
0 4 8 16 19 31
Identification Flags Fragment Offset
Time to Live Protocol Header Checksum
Source Address
Destination Address
IPv4
Header
15
Options + Padding
Data Field
IP Addresses
16
-
8/13/2019 04 Mobile+Internet+Part+1
8/15
IP Address Example
IP addresses can be in binary form (32 bits) or indotted decimal notation, w.x. .z 8 bits each
Given the following binary address:
10000000111000110000001100101000
Write the dotted decimal notation.
17
What is the network ID?
What is the host ID?
Global Addresses:
IP Address Assignment
The Internet Assigned Numbers Authority (IANA) is broadly
responsible for the allocation of globally-unique names and numbers
that are used in the Internet protocol.
The IANA is managed by the Internet Corporation for Ass igned
Names and Numbers (ICANN) under contract to the United States
Department of Commerce (DOC).
Regional Internet registries are used to allocate IP addresses on a
18
reg ona as s: ttps: www.ar n.net
A name indicates what we seek.
An address indicates where it is.
A route indicates how we get there.
--John Postel, former administrator of the IANA
-
8/13/2019 04 Mobile+Internet+Part+1
9/15
Domain Name
IP Address Assignment
Name, Address, Route
edu com gov mil org net uk fr
IP Address: www.wam.ece.ufl.edu
ufl ucla
ciseece
wam hcs
physics
cisco yahoo nasa nsf arpa navy acm ieee
>> nslookup www.wam.ece.ufl.edu
Server: mindy.ece.ufl.edu
128.227.220.11
Name: http.ece.ufl.edu
Address: 128.227.220.98
19
Address Exhaustion Example
A. How many Class B networks are possible in the
B. When a Class B IP address is purchased, oneClass B network ID is removed. How many host
20
IDs are removed from allocation?
-
8/13/2019 04 Mobile+Internet+Part+1
10/15
Managing Global Addresses:
Address Exhaustion(https://www.arin.net/knowledge/statistics/)
2009 IPv4 Delegations Issued By American Registry for Internet Numbers
21
Address Exhaustion Example (cont.)
C. How many network IDs are available to be
D. If a block of 20,000 network IDs were allocatedevery month, how long would the IPv4 addressspace last?
22
-
8/13/2019 04 Mobile+Internet+Part+1
11/15
Making IP Addresses Last:
Size of Routing Table at Internet Core
w/o CIDR, routing tables would have
reached 100,000 entries @ 1998
23Source: http://www.cidr-report.org/
Managing Global Packet Delivery
IP version 4 Packet
0 4 8 16 19 31
Identification Flags Fragment Offset
Time to Live Protocol Header Checksum
Source Address
Destination Address
IPv4
Header
24
Options + Padding
Data Field
-
8/13/2019 04 Mobile+Internet+Part+1
12/15
Internet Protocol version 6 (IP v.6)
The Internet Engineering Task Force (IETF).
In 1994, the result was the IP Next GenerationProtocol (IPng or IPv.6).
IPv.6 enhancements. Expanded address space.
Im roved o tion mechanism.
25
Address autoconfiguration.
Increased addressing flexibility. Support for resource allocation.
IP v.6 Mandatory Header
0 4 12 16 24 31
Payload Length Next Header Hop Limit
Source Address (128 bits)
40
octets
26
Destination Address (128 bits)
-
8/13/2019 04 Mobile+Internet+Part+1
13/15
IP v.4 versus IP v.6 Structure
IP v4 IP v6
Mandatory Header
Header Options
Mandatory Header
Optional
Extension
Headers
y es
variable
40 bytes
27
Payload/Data Payload/Data
IP v.6 Addresses Example
If a block of 1 million addresses is allocated
, .
address space last?
28
-
8/13/2019 04 Mobile+Internet+Part+1
14/15
IP v.6 Address Notation
IP v.6 uses hexadecimal notation. First every four
.
they are divided into 8 groups, separated by
colons (:).
4000:0000:0000:0000:BA5F:039A:000A:2176
= 4000:0:0:0:BA5F:39A:A:2176
= 4000::BA5F:39A:A:2176
29
IP v.4 addresses can also be represented:
0000:0000:0000:0000:0000:0000:128.227.x.y
= ::128.227.x.y
IP v.6 Address Notation Example
Abbreviate the following IP v.6 address:
0000:0000:0000:AF36:7328:0000:87AA:0398
30
-
8/13/2019 04 Mobile+Internet+Part+1
15/15
2009 IPv6 Address Assignments and
Requests
31