IP1 (1) Internetwork Basic concepts TCP/IP IP Addressing Basic router configuration Hervé TREMEUR AT&T Labs AT&T Global Network
[email protected] IP1 Training DU IRI Nice
CISCO router introduction
Contents (Cont 1) Internetwork Basic concepts y y y y y y y y y y y
Data Link Addresses TCP/ IP Overview OSI Model / TCP protocol suite Peer to Peer communication Data encapsulation and headers Router creates a logical path Frame changes on logical path Network Addresses Frame changes on logical path Address Resolution Protocol ARP Packet format
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Contents (Cont 2) 1. Interconnecting Networks with TCP/IP y TCP/IP Application Layer Overview y TCP/IP Transport Layer Overview y TCP Segment Format y Port Numbers y TCP Port Numbers y TCP Three-Way Handshaking/ Open Connection y TCP Simple Acknowledgement
CISCO router introduction
Contents (Cont.3) y y y y y y y y
TCP Sequence and Acknowledgement Numbers TCP Sequence and Acknowledgement Numbers TCP Windowing UDP SEGMENT Format Internet Layer Overview IP Datagram Protocol Field Internet Control Message Protocol
y Address Resolution Protocol y TCP/IP Address Overview
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Contents (cont.4) 2. IP Addressing y y y y y y y
IP Addressing IP Address Classes IP Address Classes Hosts Addresses Determining Available Host Addresses Written Exercise 1 : IP Address Classes Addressing without Subnets
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Contents (cont.5) y y y y y y y y y y
Addressing with Subnets Subnet Addressing Subnet Mask Decimal Equivalent of Bit Patterns Addressing Summary Example Class B Subnet Example Class B Subnet Example (cont.) Subnet Planning Class B Subnet Planning Example Class B Subnet Planning Example
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Contents (cont.6) 3. Router configuration y y y y y y y y y y
IP Address Configuration IP Host Command Name Server Configuration Name System How Host command Show Host command ( cont.) Verifying Address Configuration Ping Command Extended Ping Command Trace Command
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Data Link Addresses Message DATA
Return address
=== ===
Destination address
Destination address
Return address
DATA
y When data is to be delivered on a LAN it is encapsulated within an entity called frame
y A frame is a kind of binary envelope y Postal service needs a destination address to deliver the letter
CISCO router introduction
TCP/ IP Overview Workstation
Workstation
Internet
TCP / IP
y TCP / IP suite protocol was developed by the Defense Advanced Research Projects Agency (DARP), later was TCP/IP was included with the Berkeley Software Distribution of UNIX
y The Internet Protocols can be used to communicate across any set of
interconnected networks. They are equally well suited for LAN and WAN communication.
y Internet protocol suite includes Layer 3 and 4 specifications (IP TCP / IP) and also for applications (e-mail, remote login, terminal emulation, file transfer)
CISCO router introduction
OSI Model / TCP protocol suite OSI
TCP / IP
Application Presentation
Application
Session Transport
Transport
Network
INTERNET
Data-Link
Data-Link
Physical
Physical
y TCP/IP Protocol stack maps closely to the Open System Interconnection ( OSI) reference Model in the lower layer, All standard physical and data-link protocols are supported
y TCP/IP Information is transferred in a sequence of datagrams. One message may be tranmitted as a serires of datagrams that are reassembled into the message at the receiving location
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Peer to Peer communication HOST A
HOST B
Application
Transport INTERNET Data-Link Physical y y y y y
Application
TCP segment IP Packet Frame Bits
Transport INTERNET Data-Link Physical
Each layer uses its own protocol to communicate with its peer Transport layer of TCP/IP uses segments The TCP segments becomes part of the network layer packets In turns the packets become part of the data link frames Ultimately becomes bits transmitted by the physical layer
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Data encapsulation and headers A user makes a request to open a specific page by sending the URL ( uniform Resource Locator) to the WEB server
Web Request
DATA Transport Header DATA
Data TCP header with
Segment
Network Transport Header Header DATA
Packet
Frame Network Transport Frame Header Header Header DATA Check
10100111100010101010101010101010101
Frame ( Medium dependant)
Bits
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Router creates a logical path Logical Path between networks
1.1
4.2
Token-ring
FDDI Ring
Network 1
Network 2
Neywork 3
Network 4
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Network Addresses
Logical Path between networks
1.2
FDDI 1.2 4.2 DATA
2.2
2.1 1.1
Network 1 ETHERNET1.2 4.2 DATA
SERIAL 1.2 4.2 DATA
3.1
3.2
4.1 Token-ring
FDDI Ring
Network 2
4.2
Network 3
Network 4 TOKEN RING 1.2 4.2 DATA
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Frame changes on logical path
Logical Path between networks
1.2
FDDI 1.2 4.2 DATA
SERIAL 1.2 4.2 DATA
Token-ring
FDDI Ring
Network 1 ETHERNET1.2 4.2 DATA
Network 2
4.2
Network 3
Network 4 TOKEN RING 1.2 4.2 DATA
CISCO router introduction
Frame changes on logical path (2) Host H1
Host H2
1.2 3.2
DATA Transport Header DATA
Process in Router B
Process in Router A
Network Transport Header Header DATA
Network Transport Header Header DATA
Frame Network Transport Frame Header Header Header DATA Check
1010011110001010101010101
Transport Header DATA
NetworkTransport Header Header DATA
Frame Network Transport Frame Header Header Header DATA Check
Frame Network Transport Frame Header Header Header DATA Check
1010011110001010101010101
1010011110001010101010101
2.1
2.2
1.1
3.1
FDDI Ring
Network 1
DATA
Router A
Network 2
Router B Network 3
CISCO router introduction
Frame changes on logical path (3) Host H1
Host H1 Mac@H1 Mac@H2
1.2
3.2
DATA Transport Header DATA
Process in Router B
Process in Router A
[email protected] Transport IP@ 3.2 Header DATA
[email protected] Transport IP@ 3.2 Header DATA
Mac@H1
[email protected] Frame Mac@A1 IP@ 3.2 Header DATA Check
1010011110001010101010101
1.1
Mac@A2
[email protected] Transport Frame Mac@B2 IP@ 3.2 Header DATA Check
Mac@B2
Mac@A2
Mac@A1
Transport Header DATA
[email protected] Transport IP@ 3.2 Header DATA Mac@B3
[email protected] Transport Frame Mac@H2 IP@ 3.2 Header DATA Check
1010011110001010101010101
1010011110001010101010101 2.1
DATA
2.2 3.1 Mac@B3
FDDI Ring
Network 1
Router A
Network 2
Router B Network 3
CISCO router introduction
Address Resolution Protocol •I heard that broadcast. The message is for me. Here is my Ethernet address
•I need the Ethernet address of 172.20.5.2
172.20.5.1 SP
172.20.5.2 DP
IP : 172.20.5.2 = ? ? ? IP : 172.20.5.2 Ethernet : 0800.0020.1111
Map IP
MAC Local ARP
yARP is used to resolve or map a known IP address to a MAC sublayer address in order to allow communication on a multi-access medium such as Ethernet. To determine a destination MAC address for a datagram, a table called the ARP cache is checked. If the address is not in the table, ARP sends a broadcast that will be received by every station on the network, looking for the destination station.
yThe term "local ARP" is used to describe the search for an address when the requesting host and the destination host share the same medium or wire.
CISCO router introduction
ARP Packet Format Protocol Type Port (16)
Hardware Type (16) Harware Address Length
Protocol Address length
Operation
Sender Hardware Address Sender Hardware Address Sender IP Address
Target Hardware Address
Target Hardware Address Target IP Address
Common Hardware Type codes
Sender IP Address
1
Ethernet
3
X25
4
Token Ring
6
IEEE 802
15
Frame Relay
16
ATM
17
HDLC
18
Fiber channel
20
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Application Layer Overview
Application
Transport Internet
Computer applications
Network applications
Internetwork applications
Word processing
Electronic Mail
Presentations Text Graphics (JPEG,GIF) Data (ASCII,EBCDIC) Audio Video (MIDI,MPEG)
File Transfer
Electronic data Interchange
Remote Access
World Wide Web E-mails –Gateways
Network Management
Spreadsheets
Oothers
Financial transaction services
Database
Data-Link
Design Project planning
Internet navigation utilities Conferencing Video, voice, data
Physical
y JPEG : Joint Photographic Experts Group (picture format standars) y MIDI : Musical Instrument Digital Interface (Digitized music) y MPEG : Motion Pictures Experts Group ( standard for compression and coding motion video, bits rate up to 1.5 Mbps)
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Application Layer Overview (2) File transfer -TFTP - FTP - NFS E-Mail
Application Transport Internet Data-Link Physical
-SMTP Worl Wide WEB - HTTP Remote Login - Telnet - rlogin Network Management - SNMP Name Management -DNS
y Application protocols exist for file transfer, e-mail, and remote login . y Network management is also supported at the application layer. y Telnet, rlogin, SNMP, DNS are also used by the router
CISCO router introduction
Transport Layer Overview Transmission Control
connection oriented
Protocol (TCP)
Application
User Datagram
Connectionless
Protocol (UDP )
Transport Internet Data-Link Physical
y y y y
Flow control provided by sliding windows Verification provided by sequence numbers and Acknowledgements TCP : Connection oriented protocol UDP Connectionless and unacknowledged , it depends on upper layer protocols for verifications
CISCO router introduction
TCP Segment Format Source Port (16)
Destination Port (16)
Sequence
Number (32)
Acknowledgement Number (32) Header
Reserved (6)
Length (4)
Code Bits (6)
Checksum (16)
Window (16) Urgent (16)
Options (0 or 32 if any) Data (Varies)
y y y y y y y y y y y y
Source Port – Number of the calling port Destination Port – Number of the called Port (16 Bits) Sequence Number- Number used to ensure correct sequencing of the arriving data (32 bits) Acknowledgement Number – Next Expected TCP octet (32 bits) Header Length – Number of 32 bit words in the Header (4bits) Reserved – Set to 0 (6bits) Code bits – Control functions such as setup and termination of a session ( 6bits) Window – Number of Octets that the device is willing to accept Checksum – Calculated checksum of he Header and data fields (16 bits) Urgent – Indicates the end of the urgent data (16 bits) Options – one currently defined : Maximum TCP segment size (0 or 32 bits if any) Data – Upper-Layer protocol data (varies)
CISCO router introduction
Port Numbers
Application LAYER
F
T
S
H
B
D
T
S
S
T
R
T
E
M
T
G
N
F
N
N
R
I
P
L
T
T
P
S
T
M
M
A
P
N
P
P
P
P
P
P
69
161
162
E T 21 Transport LAYER
y y y y
23
25
TCP
80
179
53
520
UDP
Both TCP and UDP use port ( socket) to pass information to the upper level Well known port numbers (below 1024) controlled by Internet Assigned Numbers Authority (IANA) Numbers 1024 and above are dynamically assigned ports. Registered port numbers are those registered for vendor-specific applications
Å Port Numbers
CISCO router introduction
TCP Port Number HOST A
Source
Destination
port
port
HOST B
TELNET B
SP
DP
1028
23
•DP = 23 send •Packet to •Telnet •Application
yEnd systems use port numbers to select the proper application. Originating source port numbers are dynamically assigned, by the Source Host, some number greater than 1023
CISCO router introduction
TCP Three-Way Handshake / Open Connection HOST B HOST A
1
Send SYN (Seq=100 ctl=SYN
SYN Received
3 y y y y
SYN Received Send SYN, ACK (Seq=300 ack= 101
2
Established (Seq=101 ackl=301 ctl=ack
TCP is connection-oriented, it requires connection establishment before data transfer begins. 1) A-Æ B SYN my sequence number is X, ACK number is 0 , ACK bit is not set 2) A Å B ACK your sequence number is X+1, SYN my sequence number is Y, ACK Bit is set. 3) A -> B ACK your sequence number is Y+1, my sequence number is X+1, ACK Bit is set.
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TCP Simple Acknowledgement Receiver Sender
Send 1 Received ACK 2 Send 2
Received ACK 3 Send 3 Received ACK 4
Receive 1 Send ACK 2
Receive 2 Send ACK 3 Receive 3 Send ACK 4
y The window size determine how much data the receiving station can accept at one time. with a window size of 1, each segment must be acknowledged before another segment is transmitted, efficient use of bandwidth
CISCO router introduction
TCP Sequence and Acknowledgement Numbers Source
Destination Port
Port
Sequence
Acknowledg ement
Just send Number 11
1028
23
I just got Number 11, Now I need number 12
10
100 23
1028
23
-------------
11
10 28
100
11
1000 23
10 28
101
12
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TCP Windowing Sender Window size =3, Send 1
Window Size = 2
Window size=3, Send 2 Window size=3, Send 3 ACK=3 Window Size = 2
PACKET 3 is Dropped
Window size=3, Send 3 Window size=3, Send 4 ACK=5 Window Size = 2
y TCP uses a flow control yThe receiving TCP reports a WINDOW to the sending TCP ( Number of Octets starting with ACK yWindow cut in half in case of congestion yTCP window size is documented in RFCs 793 and 813
CISCO router introduction
UDP SEGMENT Format Source Port (16)
Destination Port (16)
Length (16)
Checksum (16) DATA ( if any)
y No sequence or acknowledgement fields y UDP uses no windowing or acknowledgement y Source port --- Number of the calling port (16 bits) y Destination port --- Number of the called port (16 bits) y Length ---Length of UDP header and UDP data (16 bits) y Checksum --- Calculated checksum of the header and data fields (16 bits) y Data --- Upper layer Protocol data (varies) y Protocols using UDP : TFTP, SNMP, NFS and DNS
CISCO router introduction
Internet Layer Overview
Application
Internet (IP)
Transport
Internet Control Message Protocol(ICMP)
Internet Data-Link
Address Resolution Protocol (ARP) Reverse Address Resolution Protocol (RARP)
Physical y Several protocols operates at the TCP/IP internet layer, which corresponds to the OSI model network layer y IP provides connectionless, best effort delivery routing of datagrams. Not concerned with data contents but the way to move the datagrams to the destination
y The Internet Control Message Protocol ( ICMP) provides control and messaging capabilities y The Address Resolution Protocol (ARP) determines the Data-link layer address for known IP address y The Reverse Address Resolution Protocol (RARP) determines network address when data link layer address are known
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IP Datagram Version (4)
Header Length (4)
Priority and Type of service (8)
Identification (16) Time-to-live (8)
Total Length (16) Flags (3)
Protocol (8)
Fragment Offset (1)
Header Checksum ( 16)
Source IP address (32) Destination IP Address (32) OPTIONS (0 or 32 any) Data ( Varies)
y VERS -- version number y HLEN -- header length, in 32-bit words y type of service -- how the datagram should be handled y total length -- total length (header + data) y identification, flags, flag offset -- provides y fragmentation of datagrams to allow differing MTUs in the internetwork y TTL -- Time-To-Live y protocol -- the upper-layer (Layer 4) protocol sending the datagram y header checksum -- an integrity check on the header y source IP address and destination IP address - 32-bit IP addresses y IP options -- network testing, debugging, security, and other options y Data ---Upper-Layer protocol data (varies)
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Protocol Field Transport Layer
UDP
TCP 6
Internet Layer
17 IP
ÅProtocol Numbers
y The protocol field determines the Layer 4 being carried within IP datagram y Each IP Header must identify the destination Layer 4 protocol y P includes the protocol number in the protocol field Protocol
Protocol Field
Internet Control Message Protocol (ICMP)
1
Interior Gateway Routing Protocol (IGRP)
9
IP Version 6 (IPV6)
41
Generic Routing Encapsulation (GRE)
47
Internetwork Packet Exchange in Internet Protocol
111
Layer 2 Tunneling Protocol (L2TP)
115
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Internet Control Message Protocol
Application
Destination Unreachable
Transport Echo (Ping)ol(ICMP)
ICMP Other
Internet Data-Link Physical
y
All TCP/IP hosts implement ICMP. ICMP messages are carried in IP datagrams and are used to send error and
control messages. ICMP uses the following types of defined messages. Others exist that are not included on this list
y y y y y y y
Destination Unreachable Time to Live Exceeded Parameter Problem Source Quench Redirect Echo Echo Reply
y y y y y y
Timestamp Timestamp Reply Information Request Information Reply Address Request Address Reply
CISCO router introduction
TCP/IP Address Overview
172.21.0.1
172.20.0.2 172.20.0.1 172.22.0.1
10.13.0.0
y y y y
10.13.0.1
HDR
172.21.0.2
192.168.1.0
172.22.0.2 SA
DA
DATA
192.168.1.1
Unique Addressing allows Communication between end Stations Path choice is based on destination Address Each IP datagram includes Source IP Address and Destination IP Address Each Company on the Internet is seen as a single network.
CISCO router introduction
IP Addressing 32 Bits Dotted Decimal
NETWORK
Maximum
255
1 Binary
11111111
HOST 255
8
255
16 11111111
255
24
32
11111111
11111111 1 6 3 1 8 2 4 2 6
4 2 1
8
Example Decimal Example Binary
172
16
122
204
10101100
00010000
01111010
11001100
y The IP Address is 32 Bits in Length and has 2 parts : Network and Host number y The Address format is known as dotted decimal notation y Minimum value for an octet is 0 ( all 0 s) y Maximum value for an Octet is 255 (all 1s)
CISCO router introduction
IP Address Classes
8 Bits
8 Bits
8 Bits
8 Bits
Class A:
Network
Host
Host
Host
Class B:
Network
Network
Host
Host
Class C:
Network
Class D:
MULTICAST
Class E:
Research
y y y y y
Network
Network
Host
Class A : 8 Network bits and 24 bits in the Host field, class A networks are rare Class B : 16 Network bits and 16 bits in the Host field Class C : 24 Network bits and 8 bits in the Host field Class D : Addresses starts at 224.0.0.0 Class E : Addresses begin at 240.0.0.0
CISCO router introduction
IP Address Classes 1
8
9
16
17
24
25
Class A:
0NNNNNNN
Host
Host
Host
Class B:
10NNNNNN
Network
Host
Host
Network
Network
Class C: Class D:
y y y y y
110NNNNN
1110MMMM
Multicast
Multicast
32
Host
Multicast
Class A : First bit is 0 , Network 1.0.0.0 to 126.0.0.0, 127 networks,16 777 216 Hosts Class B : First 2 bits 10 , Network 128.0.0.0 to 191.255.0.0, 16384 networks, 65 536 Hosts Class C : First 3 bits 110 , Network 192.0.0.0 to 223.255.255.0, 2097152 networks, 254 Hosts Class D : First 4 bits 1110 , Network 224.0.0.0 to 239.255.255.255 10.0.0.0, 172.16.0.0 to 172.31.0.0 and 192.168.0.0 are private and not used in public network.
CISCO router introduction
Hosts Addresses 10.6.1.2 172.20..2.2
10.6.1.1 E0 10.6.1.3
172.20.2.3
172.20.2.1
E1 10.6.1.4
172.20.2.4 Routing Table
Network 172.20. Network y y y y
2.4 Host
Interface
172.20.0.0
E0
10.0.0.0
E1
Each device or interface must have a non zero number A value of 0 means this network A host address of all 1s is reserved for IP broadcast into that network Routing table contains entries for Network or wire Addresses
CISCO router introduction
Determining Available Host Addresses Network
Host
172
16
0
0
10101100
00010000
00000000
00000000
00000000
00000001
00000000
00000010
11111111
11111111
65536
2**(N)-2 = 2**(16)-2 =65534
y Once the network portion is determined, we can determine the total number of Hosts by the formula 2 **(N) – 2
y Subtract 2 ( 1 address of all 0s for network , 1 address of all 1s for broadcast address)
CISCO router introduction
Written Exercise 1 : IP Address Classes Address
Class
Network
Host
10.2.1.1 128.83.2.100 201.222.5.64 192.6.141.2 130.113.64.16 256.221.20.10
y Identify the appropriate class ( A, B or C), network component and host component for each address.
CISCO router introduction
Addressing without Subnets
172.20.0.1
172.20.0.2 172.20.0.3
172.20.1.1 172.20.1.2
172.20.1.3
Network 172.20.0.0
y All datagrams addressed to network 172.20.0.0 are treated in the same way, regardless of the third and the fourth octet of the address.
y All subsystems on the network encounter all the broadcast on the network, can result in poor performance
CISCO router introduction
Addressing with Subnets
172.20.2.1
172.20.2.2 172.20.2.3
Network 172.20.2.0
172.20.1.1 172.20.1.2
172.20.1.3
Network 172.20.1.0
y Dividing the network into smaller segments, or subnets, makes the network address use more efficient . From outside the network is seen in the same way .
y In the example, network 172.20.0.0 is subdivided into 2 subnets, 172.20.1.0 and 172.20.2.0. Router determine the destination network using the subnet address, limiting the amount of traffic on the network segment.
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Subnet Addressing 172.20.2.2 172.20.1.2
172.20.2.1 E0 172.20.2.3
172.20.1.3
172.20.1.1
E1 172.20.2.4
172.20.1.4 Routing Table
Network 172.20
1
Network
4
Subnet Host
Interface
172.20.1.0
E0
172.20.2.0
E1
y Subnets are an extension of the network number . y A network uses a subnet Mask to determine what part of the IP address is used for the network, the subnet, and y
the device (host) address. A subnet Mask is a 32 bit value containing a number of 1 bits for the network and subnet ID, and a number of 0 bits for the Host Id.
CISCO router introduction
Subnet Mask Network IP Address
Host
172
16
0
Network Default Subnet Mask 8-Bit Subnet Mask
255
0
Host 255
Network 255
0
Subnet 255
255
0
Host 0
y Subnet are taken from the Host field of the Subnet. The number of subnet bits taken from the host field is identified by a subnet mask.
y Each bit in the subnet mask is used to determine how the corresponding bit in the IP address has to be interpreted :
9 Binary 1 for the network and subnet bits 9 Binary 0 for the host bits
y The subnet mask can be denoted as follows 9 Dotted decimal : 255.255.255.0 9 Bit count : / 24 9 Hexadecimal : 0xFFFFFF00
CISCO router introduction
Decimal Equivalent of Bit Patterns 128
64
32
16
8
4
2
1
0
0
0
0
0
0
0
0
=
0
1
0
0
0
0
0
0
0
=
128
1
1
0
0
0
0
0
0
=
192
1
1
1
0
0
0
0
0
=
224
1
1
1
1
0
0
0
0
=
240
1
1
1
1
1
0
0
0
248
1
1
1
1
1
1
0
0
= =
1
1
1
1
1
1
1
0
254
1
1
1
1
1
1
1
1
= =
252
255
y Subnet bits come from the high-order bits of the host field y To determine a subnet mask for an address, add the decimal value of each position that has a 1 in it . For example : 224 = 128 + 64 + 32
CISCO router introduction
Subnet without Subnet Mask
NETWORK 172.16.2.160 255.255.0.0
Network Number
SUBNET
HOST
10101100
00010000
00000010
10100000
11111111
11111111
00000000
00000000
10101100
00010000
00000000
00000000
172
16
0
0
y Subnets not in use --- the default y The router performs a logical AND operation to obtain the network number (host portion removed)
CISCO router introduction
Subnet with 24 bits (Network+Subnet) Mask
NETWORK
SUBNET
HOST
172.16.2.160
10101100
00010000
00000010
10100000
255.255.255.0
11111111
11111111
11111111
00000000
10101100
00010000
00000010
00000000
Network Number
172
16
2
0
y Network Number extended by eight bits y With eight bits of subnetting, the extracted network (subnet) number is 172.16.2.0
CISCO router introduction
Subnet with 26 bits (Network+Subnet) Mask
NETWORK
SUBNET
HOST
172.16.2.160
10101100
00010000
00000010 10
100000
255.255.255.192
11111111
11111111
11111111 11
000000
10101100
00010000
00000010 10
000000
Network Number
172
16
2
128
y Network Number extended by 10 bits y With ten bits of subnetting, the extracted network (subnet) number is 172.16.2.128
CISCO router introduction
Written Exercise 2 : Subnet Mask Subnet Address
Mask
172.16.12.10
255.255.255.0
10.6.24.20
255.255.240.0
10.30.36.12
255.255.255.0
192.6.141.2
255.255.255.0
130.113.64.16
255.255.240.0
221.241.20.10
255.255.248.0
Class
Subnet
y Determine the address class and calculate the subnet of a given network address y Write the address class and subnet number next to the IP address in the table
CISCO router introduction
Written Exercise 2 : result Subnet Address
Mask
Class
Subnet
172.16.12.10
255.255.255.0
B
172.16.2.0
10.6.24.20
255.255.240.0
A
10.6.20.0
10.30.36.12
255.255.255.0
A
10.30.36.0
192.6.141.2
255.255.255.0
C
192.6.141.0
130.113.64.16
255.255.240.0
B
130.113.64.0
221.241.20.10
255.255.248.0
C
221.241.16.0
y Determine the address class and calculate the subnet of a given network address y Write the address class and subnet number next to the IP address in the table
CISCO router introduction
Broadcast Address
172.20.3.0 172.20.2.1 172.20.4.0 172.20.2.0 172.20.1.0 172.20.3.255 Directed Broadcast 255.255.255.255 Local Network Broadcast 172.20.255.255 All Subnets Broacast Directed Broadcast y y y y
Cisco IOS supports three kinds of broadcasts as follows : Flooding (flooded broadcast are not propagated but are considered as local broadcast) Directed Broadcast (broadcast a message to all hosts within a single subnet) All subnets broadcast (Broadcast a message to all hosts on all subnets)
CISCO router introduction
Addressing Summary Example 172
16
NETWORK
2
128
SUBNET
HOST
10101100
00010000
00000010 10
100000
Host
255.255.255.192 11111111
11111111
11111111 11
000000
Mask
172.16.2.128
10101100
00010000
00000010 10
000000
Subnet
172.16.2.191
10101100
00010000
00000010 10
111111
Broadcast
172.16.2.129
10101100
00010000
00000010 10
000001
First
172.16.2.190
10101100
00010000
00000010 10
111110
Last
172.16.2.160
y Draw a line after the last contiguous subnet mask 1 bit y On the right side place all 0 ‘s in the remaining spaces. This will be the subnet y In the next row place all 1’s in in the remaining spaces. This will be the broadcast address
CISCO router introduction
Class B Subnet Example IP Host Address : 172.16.2.121, Subnet Mask : 255.255.255.0
NETWORK
SUBNET
HOST
172.16.2.121
10101100
00010000
00000010
01111001
Host
255.255.255.0
11111111
11111111
11111111
00000000
Mask
172.16.2.0
10101100
00010000
00000010
00000000
172.16.2.255
10101100
00010000
00000010
11111111
Subnet Broadcast
172.16.2.1
10101100
00010000
00000010
00000001
First
172.16.2.254
10101100
00010000
00000010
11111110
Last
y This network has eight bits of subnetting that provide up to 254 subnets and 254 hosts addresses
CISCO router introduction
Class B Subnet Example (cont.) Number of bits
Subnet Mask
Number of Subnets
Number of Hosts / Subnet
17
255.255.128.0
2
32766
18
255.255.192.0
4
16382
19
255.255.224.0
8
8190
20
255.255.240.0
16
4094
21
255.255.248.0
32
2046
22
255.255.252.0
64
1022
23
255.255.254.0
128
510
24
255.255.255.0
256
254
25
255.255.255.128
512
126
26
255.255.255.192
1024
62
27
255.255.255.224
2048
30
28
255.255.255.240
4096
14
29
255.255.255.248
8192
6
30
255.255.255.252
16384
2
CISCO router introduction
Subnet Planning 3 subnets 10 Hosts / subnet Class C Address 192.168.5.16
192.168.5.32
y Class C Address 192.168.5.0, y 20 subnets are needed, y
5 hosts/ subnet
192.168.5.48
192.168.5.0
CISCO router introduction
Class C Subnet Planning Example 1 IP Host Address : 192.16.2.121, Subnet Mask : 255.255.255.248
NETWORK
Network
Subnet Host
11000000
00010000
00000010
01111 ! 001
Host
255.255.255.248 11111111
11111111
11111111
11111 ! 000
Mask
192.16.2.120
11000000
00010000
00000010
01111 ! 000
192.16.2.127
11000000
00010000
00000010
192.16.2.121
11000000
00010000
00000010
01111 ! 001
192.16.2.126
11000000
00010000
00000010
01111 ! 110
192.16.2.121
y
Subnet 01111 ! 111 Broadcast First Last
CISCO router introduction
Class C Subnet Planning Example 2 IP Host Address : 192.16.2.121, Subnet Mask : 255.255.255.252
NETWORK
Network
Subnet Host
11000000
00010000
00000010
011110 ! 01
Host
255.255.255.252 11111111
11111111
11111111
111111 ! 00
Mask
192.16.2.120
11000000
00010000
00000010
011110 ! 00
192.16.2.123
11000000
00010000
00000010
192.16.2.121
11000000
00010000
00000010
011110 ! 01
192.16.2.122
11000000
00010000
00000010
011110 ! 10
192.16.2.121
y
Subnet 01111 0 ! 11 Broadcast First Last
CISCO router introduction
Class C Subnet Possibilities
Number of bits
Subnet Mask
Number of Subnets
Number of Hosts / subnet
1
255.255.255.128
2
126
2
255.255.255.192
4
62
3
255.255.255.224
8
30
4
255.255.255.240
16
14
5
255.255.255.248
32
6
6
255.255.255.252
64
2
CISCO router introduction
IP Address Configuration
CISCO router introduction
IP Host Command
CISCO router introduction
Name Server Configuration
CISCO router introduction
Name System
CISCO router introduction
How Host command
CISCO router introduction
Show Host command ( cont.)
CISCO router introduction
Verifying Address Configuration
CISCO router introduction
Ping Command
CISCO router introduction
Extended Ping Command
CISCO router introduction
Trace Command
