Internet: network nodes
description
Transcript of Internet: network nodes
Faruk Hadziomerovic: Internet notes
Internet: network nodes
Host: any computer executing protocol
Hub: repeats signal heard one each port to all ports.
Bridge: understands physical layer addresses, MAC addresses, and learns where each device is located. It listens to all traffic on LAN. If it finds that packet should go to another segment it forwards the frame to it. It is store-and-forward device.
Switch: same as bridge however much faster. It redirects a frame only after readingdestination address on a ongoing basis.
Router: Internetwork layer device. It reads entire packet, based on destination address finds the best route for the packet and sends it.
Faruk Hadziomerovic: Internet notes
Internet: network of networks
star star
Ethernet Ethernet
token ring
hub
hub
bridge
bridge
bridge
switch
router
Faruk Hadziomerovic: Internet notes
Internet protocol stack vs. OSI model (Fig. 1.2)
Physical Layer
Presentation Layer
Session Layer
Transport Layer
Network Layer
Data Link Layer
Application Layer
Manchester
Ethernet, Token ring (ATM, Frame Relay**)
IP, ARP
TCP, UDP
E-mail, FTP, HTTP
Physical Layer
Host-to-host Layer
Internet Layer
MAC* Layer
Process Layer
* Medium Access Control. MAC and Physical layers are called Network Interface Layer.** not exactly MAC, however, layer above physical
Faruk Hadziomerovic: Internet notes
Two networks connected with a router (Fig. 1.3)
FTPclient
TCP
IP
Ethernet driver
Ethernet driver
Token ring driver
Token ring driver
FTPserver
TCP
IP IP
FTP protocol
TCP protocol
Ethernet
router
Ethernet protocol
IP protocolIP protocol
Ethernet protocol
Token ring
Ethernet host Token ring host
Faruk Hadziomerovic: Internet notes
Internet protocol suite
Telnet
FTP
HTTP
DNS
BOOTP
DHCP
SNMP
TFTP
RIP
23 20/21 80 53 67/68 69 151/162 520
TCP UDP
6 17
IP
IGRP
88
ICMP
01OSPF
89
ARP RARP
Process Layer
Host to Host Layer
Internet Layer
Network InterfaceLayer
08000806 0806
Port Numbers
Protocol Codes
Ethernet, Token Ring, FDDI, SLIP, PPP, etc.
Faruk Hadziomerovic: Internet notes
Internet protocols
TELNET - remote terminal connection service. Allows user terminal to mimic the terminal at the remote side.FTP - File Transfer Protocol (put/get file to/from remote machine).HTTP - Hypertext Transport Protocol.DNS - Domain Name Server On-line distributed database for translating IP machine names into IP addresses.BOOTP - Bootstrap Protocol defines each device autoconfiguration on the server (improvement to the RARP).DHCP - Dynamic Host Configuration Protocol (improvement to BOOTP) allows network administrator to configure workstation by providing dynamic address assignment.TFTP - Trivial File Transfer Protocol (same as FTP with minimal capability).SNMP - Simple Network Monitoring Protocol used to monitor IP gateways and networks they are attached to.RIP - Routing Information Protocol used to exchange the routing information among small set of computers (every 30 sec hosts exchange information).TCP - reliable Transmission Control Protocol (connection oriented).UDP - unreliable Universal Transport Protocol (connectionless).IGRP - Interior Gateway Routing Protocol (proprietary routing protocol developed by Cisco). ICMP - Internet Control Message Protocol part of IP that handles error and control messages.OSPF - Open Shortest Path First routing protocol.ARP - Address Resolution Protocol used to dynamically bind IP addresses to physical addresses.RARP - Reverse ARP used by newly installed machine to find its IP address.IP - Internet Protocol.
Faruk Hadziomerovic: Internet notes
Encapsulation (Fig. 1.7)
Ethernet
14 bytes 20 to 60 bytes
IP header
UDP
8 bytes variable
Application
TCP
20 or 24 variable
Application
ICMP
6 + bytes
CRC
4 bytes
Faruk Hadziomerovic: Internet notes
Demultiplexing (Fig. 1.8)
application
TCP
IP
Ethernet driver
UDP
ICMP
incoming frame
application application application
IGMP
RARPARP
Faruk Hadziomerovic: Internet notes
Sample (book) network
aix
.1.92
gateway
.1.4
bsdi
.13.35
solaris
.1.32
gemini
.1.11
Solaris 2.2 SunOS 4.1.1
Ciscorouter
netb
.1.183
TelebitNetBlazer
modem
sun
.1.29SunOS 4.1.3modem
.13.33
SLIP (dialup)
svr4
.13.34
SVR4BSD/386 1.0
.13.66slip
.13.65
BSD/386 1.0
Ethernet
Ethernet
All IP addresses belong to class B network ID 140.252.xxx.xxx
Faruk Hadziomerovic: Internet notes
Link Layer (Fig. 2.1)
SLIP (Serial Line IP)
c0 db dc db dd c0
c0 db
ESC
Point-to-point (PPP) protocol
IP datagram
Flag 7E
Contr 03
protocol
0021
1 1 1 2 up to 1500 2 1
CRCdataaddr FF
Flag 7E
Link control dataC021
network control data8021
Faruk Hadziomerovic: Internet notes
Ethernet Header
Destin. Addr. Source Addr. Type
Vendor addr component
Broadcast
ff ff ff ff ff ff 00 00 c0 a0 51 24 08 06
Unicast ARP
Multicast
01 00 5e 00 00 00 00 00 c0 a0 51 24 08 00
Unicast IP
Unicast
01 00 c0 a0 51 24 00 c0 93 21 88 a7 81 4c
Unicast SNMP
Vendor ser. number
Faruk Hadziomerovic: Internet notes
IP addressing convention4 bytes (dec): 140.252.1.13 = 01100000.10101010.00000001.00001011
Class A: Large networks (GM, Ford, etc)
0NNNNNNN LLLLLLLL LLLLLLLL LLLLLLLL
N-Network bitsL-Locally administered126 Class A networks16,777,214 hosts/network
0 - unused, 1 .. 126 ; 127 - loop back
10NNNNNN NNNNNNNN LLLLLLLL LLLLLLLL 16,384 Class B networks65,534 hosts/network(0 not used, all 1’s broadcast) 128 .. 191 0 .. 255
Class B: medium size (universities, medium business)
110NNNNN NNNNNNNN NNNNNNNN LLLLLLLL 2,097,152 Class C networks254 hosts/network
192 .. 223 0 .. 255 0 .. 255
Class C: small networks (small business)
1110MMMM MMMMMMMM MMMMMMMM MMMMMMMM 2,097,152 Class C networks254 hosts/network
224 .. 239 0 .. 255 0 .. 255 0 .. 255
Class D: broadcasting
Faruk Hadziomerovic: Internet notes
IP subnetting with subnet masks
IP address: 191 255 193 44
Subnet mask: 255 255 252 000
Binary addr: 10111111 11111111 11000001 00101100
Binary Mask: 11111111 11111111 11111100 00000000
Address bits: NNNNNNNN NNNNNNNN SSSSSSI I I I I I I I I I
N - network bitsS - subnet bitsI - Interface bits.
Natural masks:
Class A : 255.0.0.0 B : 255.255.0.0 C : 255.255.255.0
Faruk Hadziomerovic: Internet notes
Subnetting example
source: 161.55.121.33target: 161.55.131.49
mask: 255.255.248.0
248 = 11111000 mask121 = 01111001 source
subn= 01111 source subnet
248 = 11111000 mask248 = 10000011 target
subn= 10000 target subnet
Are this two hosts in the same subnet?