CSIS261-3
Power of 2
0-1-Binary
0-9-Decimal
0-F-Hexadecimal
Binary Digit = Bit
1bit= 0-1
4bit= 1nibble
8bit= 1Byte
1KB= 1024Bytes
1MB= 1million Bytes
1GB= 1billion Bytes
1TB= 1trillion Bytes
204.185.156.254<--each XXX. is an octet. or 8 bits.
256 different arrangements in each octets. 0-255
204.185.156.254
2 to the numerical value
2^0
2^1
2^ up to 7
Limitations of Layer 1
-Cannot organize streams of bits.
-Cannot Name or Identify Computers
-Cannot communication with the upper level layer
-Cannot decide witch computer will transmit binary data.
Layer 2
-Layer 2 uses framing to organize group the bits.
-Layer 2 uses an addressing process to identify computers.
-Layer 2 uses the LLC to communicate with the upper level layers.
-Layer 2 uses the MAC to decide which computer will transmit.
Ethernet covers both Layer 1 and 2
802.2 only uses the LLC sub layer
802.3,10base T, Tolkenring, 802.5,FDDI-Deal with the physical
802.1d:Spanning tree,
802.2: LLC
802.3 Mac Ethernet
802.5 MAC Token Ring
802.11 WIFI
LLC-transition up to the network layer.
MAC- Transition down to media.
LLC-serves to communicate upward to Network lyare, independent of specific LAN and Upper layers
MAC- serves to access and communicate downward to the technology specific Physical layer.
INSIDE the LLC -
PDU: Protocol Data Unit
DSAP: Destination Service Access Point
MAC decides what type of frame to put it in. 802.3(Ethernet) 802.5(TOlkenRing)
Naming and Framing.
4 Concepts of Layer 2
1. Layer 2 uses farming to organiz4e or group the data.
2. Layer 2 uses a flat addressing convention
3. Layer 2 communicates with the upper level layers through LLC.
4. Layer 2 uses MAC to choose which computer will transmit binary data, from a group in which all computer are trying to transmit at the same time.
HEXADECIMAL
Base 16 system
CSIS261-4
MAC ADDRESS
Every computer has a unique way of identifying itself: MAC Address or physical address
OUI-Organizational unique Identifier - the first six HEX digits witch are administer by the IEEE identify the manufacture or vendor.
Vendor Assigned -NIC CARDS, Interfaces.
48bit=MAC Address.
1st 24bits-Vendor or OUI
Remaining 24bits-Vendor assigned Nic Cards.
24bit-6 Hex Digits-00 60 2F-CSICO
24bit-6 Hex Digits-3A 07 BC-
MAC address are sometimes referred to as BURN-IN ADDRESS (BIAs) because they are burned into the ROM and are copied into RAM when the NIC initializes.
EXP.
0000.0c.12.3456 or 00-00-0c-12-34-56
Encapsulation data packet - 1500Bytes'Giants' to 64Bytes'Runts'
MAC Disadvantages
-Flat does not work well in internetworking.
-Hardware Dependent
Encoding is the process of centering information in to frame form that can travel on a physical link.
-Which computers are communicating with one another?
-When communication between individual computer begins and when to terminate.
-A record of errors that occurred during the communication
-Whose turn it is to talk in computer conversation.
DEF of MAC
Specified by the techology being used
Determine who can transmit and when
2 types
-Deterministic: 'Take turns
-Token Ring, FDDI
-Non-deterministic:'First come, First serve'.
-Ethernet: CSMA/CD. Carrier Sense Media Access with Collision Detection
FDDI - Fiber Disruptive Data Interface
Ethernet; Logical Broadcast topology
Token Ring: logical token ring topology
FDDI:logical token ring topology.
LAYER 3 RESPONCIBILITIES
-Moves data through the set of networks.
-Use a hierarchical addressing scheme.
-Segment network and control flow traffic.
-Talk to other networks with services offered by ISPs(Internet Service Providers).
DEVICECES
Routers
-Interconnect network segments or entire networks.
-Make Logical decisions based on IP addresses.
-Determines best path of data on an internetwork.
-Layer 3 Switching
PATH DETERMINATON
-The process the router uses to choose the next hop in the path the packet travels.
-The router use the network address to identify the destination network of packet within an internetwork
-Ip address can be assign by Net administrator or dynamically
NETWORK LAYER ADDRESS
IP Ver 4
-Network layer Address are 32 bits long.
-They are represented as four octets in dotted decimal format.
EXP: 233.14.17.0
-The IP Address has two components:
-The Network ID
-Assigned By ARIN(www.ARIN.net)
-Identifies the network to witch a device is attached.
-May be identified by 1,2,or 3 of the first 3 octets.
-The Host ID
-Assigned by a Net ADMIN
-Identifies the specific device on that network.
-May be identified by 1, 2, or 3 of that last 3 octets.
-32bit Address Represented as 8bit dotted decimals
-Different class address reserve different amount of bit for the network and host portions of the address.
-Maximum number of hosts vary for each class.
- Class A has 16,777,214 available hosts (2^24 - 2)
- Class B has 65,534 available hosts( 2^16 - 2)
- Class c has 254 available hosts (2^8 - 2)
-The first address in each network is reserved for the network address and the last address is reserved for the broad caste address.
-How do you know what class an IP address is in?
-If the first octet is between:
- 0 - 127 it is a class A address
- 128 - 191 it is a class B address
- 192 - 223 it is a class c address
@@@@255 cannot be used - Class D
@@@@127 Cannot be used - Loop Back
Binary Position
Class A - 0( in the 128s place)
Class B - 1 0 ( in the 128s place and the 64s place)
Class C - 1 1 0 ( in the 128s place, the 64 place, 32 place)
BINARY
*********************************
128 64 32 16 8 4 2 1
0 0 0 0 0 0 0 0
RESERVEED ADDRESSES
-Network Address(wire address)- this is an ip address that ends with binary 0s in all host bits.
-Class A network Address example:
-113.0.0.0
-Hosts on a Network can only communicate directly with other host if they have the same network ID. If they don’t they will not be able to communicated unless there is another device connecting the networks.
?????????????????????????????
PING- Packet Internet Groper
?????????????????????????????
-Broadcast Address - is used to send data to all of the device on a network.
-broadcast IP addresses end with binary 1s in the host part of the address.
-Class B breast address EXP: 175.10.255.255
(Remember decimal 255=Bin 11111111)
@@@*#***#***#@**@#*$@*#*@*#*$@#**#*$
BASIC OF SUBNETTING
-Subnetworks are smaller division of networks.
-They provide addressing flexibility.
-AKA Subnets
-Subnet addresses are assigned locally, usually by a network administrator.
-Subnets reduce a broadcast domain.
SUBNET ADDRESSES
-Include Class A,B,C network portion plus a subnet field a host filed.
-Bits are borrowed form the host file and are designated as the subnet filed.
EXP: NETWORK-SUBNET-HOST
HOW MANY BITS CAN I BORROW?
-The min number of bits you can borrow is 2
CSIS261-5
HOW MANY BITS CAN I BORROW?
-The min number of bits you can borrow is 2.
-The max number of bits you can borrow is with 2 left.
Class A-24 bits host - 22 max num borrowed
class b-16 bits host - 14 MAX NUM
class c 8 bits host - 6 MAX BUM
DEFAL SUBNET MASKS
-Class A - 255.0.0.0
-Class B - 255.255.0.0
-Class C - 255.255.255.0
CALC A SUBNET
-We will subnet the IP Address: 223.14.17.0
-What class ip address is this? class C
STEP 1
-Determine the Default Subnet mask
-Class C default subnet mask:
-255.255.255.0
STEP 2
-Determine the number of subnets needed and hosts on the each to determine how many bits to borrow form the host ID
-NEEDED
-13 Subnets
-10 Hosts on the Subnet
STEP 3
-Figure the actual number of subnets and hosts by borrowing bits form host ID.
-Lets see how many subnets and hosts we will have by bowrrow in 4 bits form the host.
-WE get 16 possible subnets and 16 Possible host for each subnet because:
-For the 4 bits borrowed each bit can be a 1 or a 0 leaving you with 2^4 or 16 possible combination.
-The same for the 4 leftover host bits.
-Imported: There are only 14 available subnets and host on each subnet. Why?
-Because you cannot use the first and last subnet.
-Because you cannot use the first and last address within each subnet.
-For each , on is the broadcast address and one is the network address.
%%%RULE CANNOT USE the 1st and the LAST Subnet.%%%%%
(((((((((((((((((((((((((((((((((((((
Can’t use the first because it is the Broadcast
And the Last is the Network
)))))))))))))))))))))))))))))))))))))
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
-If the first octet is between:
- 0 - 127 it is a class A address
- 128 - 191 it is a class B address
- 192 - 223 it is a class c address
<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
============================
CLASS A
204.185.156.2
NNN.HHH.HHH.HHH
============================
N=Network ID
H=Host ID
============================
CLASS B
172.5.5.1
NNN.NNN.HHH.HHH
============================
============================
CLASS C
233.225.64.2
NNN.NNN.NNN.HHH
============================
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
223.14.17.0---0--XXXX HHHH
11110000 = 128+64+32+16=240
Subnet mask is: 255.255.255.240
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
STEP 4
-Determine the subnet mask.:223.14.17.0 0--XXXX HHHH
-Where X represents the borrowed bit for subnetting.
-Add the place values of X together to get eth last octet decimal values of the subnet mask.: 128+64+32+16=240
-The sub Net mask is: 255.255.255.240
-The subnet mask is used to revesal the subnet and host address fields in IP address.
STEP 5
-Determine the ranges of host addresses for each subnet.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~Have to Borrow from the High order~~~~~~~~~~~~~~~~~~~~~~
~~~~~~~~~1st.2nd.3rd.4th---Has to borrow in these orders~~~~~~~~~
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
10.10.201.8
255.255.0.0
N.X.N.H.H -- X-is where 8 bits were barrowed.
254 - subnets
65,000- hosts per subnets
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
The only address that can be changed are the Host Addresses
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
FIGURING SUBNET NETWOK ADDRESS
-STEP 1: Change the IP Host address to Binary.
-STEP 2: Change THE subnet mask to Binary.
-STEP 3: Use the BOOLEAN Operator AND to combine the 2.
-STEP 4: Convert the network binary address to dotted decimal.
+++++++++++++++++++++++++++++++++++++++++++
223.14.17.18
11011111.00001110.00010001.00010010
255.255.255.240
11111111.11111111.11111111.11110000
=
11011111.00001110.00010001.00010000
223.14.17.16
+++++++++++++++++++++++++++++++++++++++++++
Class B
Host:172.16.2.120
Subnet Mask:2555.255.255.0
10101100.00010000.00000010.01111100
AND
11111111.11111111.11111111.00000000
=
10101100.00010000.00000010.00000000
172.16.2.0
This is the lowest subnet network address. It can help determine path.
255 is always the broadcast address for the specific class.