SDLC Intro-Continue
P=Primary Unit
S=Secondary Unit
-SDLC is a primary Systems Network Architechture (SNA) link layer protocol for WAN links
-Used with PPP & multipoint links bounded & unbounded media, half & full duplex transmission, transmission facilities, and circuit switched and packet switched networks.
- Network nodes: primary and secondary
Primary - control the operation of other station called, secondaries.
P & S connected by four basic configs-
Point-to-Point - two nodes 1P & 1S
Multipoint - 1P 2xS
Loop - topology P = First & Last S (connected to first and last S)
Hub go-ahead - In bound/outbound channel
P-outb-S S-inb-P
In bound daisy-chained back to the P through each S
--------------------------------------------------------------------------------
Derivative Protocols
- IEE 802.2 LLC is a modification of HDLC for LAN enviroments
-HDLC is a compatible super set of SDLC
-Qualified logical link control is a link layer protocol defined by IBM that allows SNA to be transported across X.25 networks.
-----------------------------------------------------------------------------------
High-Level Data Link Control (HDLC)
-HDLC supports sync, full-duplex operation
-HDLC 32-bit checksum, does not support the loop or hub go-ahead configs
SDLC 1 transfer mode
HDLC Supports THREE:
Normal Response Mode (NRM) - Used by SDLC. S cannot communicate with a P until P gives permission
Asynchronous Response Mode (ARM) - S to intiate comm w/ a P unitil P have given permission
Asynchronous balanced Mode (ABM) - Combined mode ABM - act as a P or S depending on the situation - Occurs through multiple combined nodes - No permission required-
----------------------------------------------------------------------------------
Link Access Procedure Balance
- in X.25 protocol stack
- shares same frame types, and field functions as SDLC & HDLC
- Restricted to ABM
- Can be established through DTE & DCE
- Intiate call P responding S
- LAPB use of the P/F bit is different from that of other protocols
-------------------------------------------------------------------------------------
IEEE 802.2
Three types of service
T1- procides unack connectionless service
-TCP/IP componsate for this
-commonly used
T2 -connection oriented
-ack data upon receipt
-used in IBM communication
T3 -ACK service
-Factory automated enviroments
-where eroor detection is important
Upper-layer proccess use IEEE 802.2 services through service access points.
------------------------------------------------------------------------------
802.2 header DSAP - Destination service acc point
- identifies the receiving upper-layer proccesses
------------------------------------------------------------------------------
Tuesday, November 6, 2007
Monday, November 5, 2007
OPS335W9
OPS335
Lab #7 setting up web server using apache,
Assignment 2 posted
Intresting networking type commands:
netstat -an |grep :80|wc -l - how many connections you have to your apache web server
/sbin/ifconfig - to configure an interface, bring it down or up
Commands located in for:
/sbin - administrators
/bin - regular uses
arp - find out MAC address
hostname - tell you host name or change your host name
host yahoo.com - does a dns query which are handeled on port 53, you can also to ip to hostname
ssh username@hotname - its encrypted
scp - remote:/home/me/junk/* . [from] [to]
rsync - sync two directories, if you have host a and host b with 2 harddrive the firstname you do rsync the two harddrives
because identical to the other harddrive.The second time you do it it copies the files that were updates.
tcpdump - print all traffic in the network - nice to monitor what is going on.
nmap [website] - used for port scan - 65000 on Unix -
wget [website] - retrive website information -r whole website tree
Apache Shell commands
httpd - its a deamon
service httpd restart
The very first webserver was called MOSAIC by NSC government computer before IE before Mozilla.
Apache, pached mosaic, Microsoft Webserver is called IIS
50% =====apache
40% =====IIS
/etc/resolv.conf ----short form of resolver---take a domain name and convert it to an ip number
/etc/hosts - names and ip numbers for the local
/etc/nsswitch.conf - order where to look first
/var/log - contains all logging information, want to know what happen to the system \
rootkit hunter- malacious attack suspected
Assignment
A Man page, and a bash script
mkgw
interneral, masquerading
serveral designes
mkgw.8
volume 8 - fdisk
volume 1 - cat, ls
man man ^^
Lab #7 setting up web server using apache,
Assignment 2 posted
Intresting networking type commands:
netstat -an |grep :80|wc -l - how many connections you have to your apache web server
/sbin/ifconfig - to configure an interface, bring it down or up
Commands located in for:
/sbin - administrators
/bin - regular uses
arp - find out MAC address
hostname - tell you host name or change your host name
host yahoo.com - does a dns query which are handeled on port 53, you can also to ip to hostname
ssh username@hotname - its encrypted
scp - remote:/home/me/junk/* . [from] [to]
rsync - sync two directories, if you have host a and host b with 2 harddrive the firstname you do rsync the two harddrives
because identical to the other harddrive.The second time you do it it copies the files that were updates.
tcpdump - print all traffic in the network - nice to monitor what is going on.
nmap [website] - used for port scan - 65000 on Unix -
wget [website] - retrive website information -r whole website tree
Apache Shell commands
httpd - its a deamon
service httpd restart
The very first webserver was called MOSAIC by NSC government computer before IE before Mozilla.
Apache, pached mosaic, Microsoft Webserver is called IIS
50% =====apache
40% =====IIS
/etc/resolv.conf ----short form of resolver---take a domain name and convert it to an ip number
/etc/hosts - names and ip numbers for the local
/etc/nsswitch.conf - order where to look first
/var/log - contains all logging information, want to know what happen to the system \
rootkit hunter- malacious attack suspected
Assignment
A Man page, and a bash script
mkgw
interneral, masquerading
serveral designes
mkgw.8
volume 8 - fdisk
volume 1 - cat, ls
man man ^^
Saturday, November 3, 2007
DCN386 SDLC RIPv1 compile
SDLC - HDLC - FrameRelay - PPP
SDLC - Synchronous Data Link Control
SDLC - Datalink Protocol which are Point to Point protocols
The Bank and customer start a PPP so their is no Network Layer Involved
Website for SDLC frame and ALL information:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/sdlcetc.htm
Below will Summerize what was talked about in class:
SDLC + HDLC + PPP have one thing in common
Variable Datasize
- the protocol does not specify the maximum data unit
SDLC Fields
Flag |- 8 bits of information - 01111110 -|
The first zero start bit last zero end bit.
Why? - To know when the message is over because its variable datasize
Start and End bits - Marks between data.
To ward off mixed data when the bits have a consecutive 6 1bits SDLC will put an artificial 0 at the end aka bitstuffing.
---------------------------------------------------
Control Field |- 8 bits of informaiton -|
A three bit frame format field: Info Frame, Supervisory Frame, Unnumbered Frame
Info Frame
0 - in the control field, means information is being transmitted
Supervisory Frame
1 - Supervisory frame
- positive ack
- Negative ack
- Flow control Feature
Unnumbered - Used For Network Management Functions
- Shut down & restart "Banke Machines...."
--------------------------------------------------------------------
Still in the control field
|Sequence Number| - 3 bits - Can send 7 frames before an ack is demanaded
000 - Received SN
000 - Send SN
Error checking is done for the seven frames
If they are all correct their will be a supervisory frame of 111 for completeness
----------------------------------------------------------------------
Supervisory Frame
|Function Code| - 00 = means no errors
01 = errors
11 = stop sending data
----------------------------------------------------------------------
Unnumbered Frame - 5 bits -
| function code |
- Bring up down reset
- Done by a Network Manager Person
- Preforms network management functions
----------------------------------------------------------------------
Info | Supervisory | Unnumbered
| Poll Final |
- 1 bit 2 functions
- Depends on direction
We call computers usings these protocols
Central Units & Primary Units
Primary unit - control the ordered delivery of data
Polling will ask each primary unit if it has data
- When it is coming from the final primary unit a final bit is indicated
------------------------------------------------------------------------
Thats it for SDLC at this time.
-------------------------------------------------------------------------
RIPv1 - Request Ip address | Hop Count | Interface ...depending on the Hop count it will choose the lowest one as its main route to destination
- Every 20 seconds a request is made
- Does not address Subnets
-------------------------------------------------------------------------
SDLC - Synchronous Data Link Control
SDLC - Datalink Protocol which are Point to Point protocols
The Bank and customer start a PPP so their is no Network Layer Involved
Website for SDLC frame and ALL information:
http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/sdlcetc.htm
Below will Summerize what was talked about in class:
SDLC + HDLC + PPP have one thing in common
Variable Datasize
- the protocol does not specify the maximum data unit
SDLC Fields
Flag |- 8 bits of information - 01111110 -|
The first zero start bit last zero end bit.
Why? - To know when the message is over because its variable datasize
Start and End bits - Marks between data.
To ward off mixed data when the bits have a consecutive 6 1bits SDLC will put an artificial 0 at the end aka bitstuffing.
---------------------------------------------------
Control Field |- 8 bits of informaiton -|
A three bit frame format field: Info Frame, Supervisory Frame, Unnumbered Frame
Info Frame
0 - in the control field, means information is being transmitted
Supervisory Frame
1 - Supervisory frame
- positive ack
- Negative ack
- Flow control Feature
Unnumbered - Used For Network Management Functions
- Shut down & restart "Banke Machines...."
--------------------------------------------------------------------
Still in the control field
|Sequence Number| - 3 bits - Can send 7 frames before an ack is demanaded
000 - Received SN
000 - Send SN
Error checking is done for the seven frames
If they are all correct their will be a supervisory frame of 111 for completeness
----------------------------------------------------------------------
Supervisory Frame
|Function Code| - 00 = means no errors
01 = errors
11 = stop sending data
----------------------------------------------------------------------
Unnumbered Frame - 5 bits -
| function code |
- Bring up down reset
- Done by a Network Manager Person
- Preforms network management functions
----------------------------------------------------------------------
Info | Supervisory | Unnumbered
| Poll Final |
- 1 bit 2 functions
- Depends on direction
We call computers usings these protocols
Central Units & Primary Units
Primary unit - control the ordered delivery of data
Polling will ask each primary unit if it has data
- When it is coming from the final primary unit a final bit is indicated
------------------------------------------------------------------------
Thats it for SDLC at this time.
-------------------------------------------------------------------------
RIPv1 - Request Ip address | Hop Count | Interface ...depending on the Hop count it will choose the lowest one as its main route to destination
- Every 20 seconds a request is made
- Does not address Subnets
-------------------------------------------------------------------------
Friday, November 2, 2007
DCN386W9 - SDL HDLC FRAMERELAY RIPv1
Question 1 Test 2
Test 2 in week 13
Scummed the test AAAAAAAAAHHHHHHHHHHHHHHHRRRRRRRRHHHHHHHHHH!
In the course outline
2test each worth 25%,
1Q 10%
FE 40%
Test 1 20%
60/3
Question 1
It’s a protocol
SDLC- Synchronous Data link Control Protocol
For the 100$ coming out of your bank accounts, you use SDLC
IBM’s protocol very expensive
OSI changed SDCL to –HDLC-
HDLC is ciscos default datalink protocol, if you understand SDLC you will understand HDLC
This is a data link layer protocol
IETF renamed it to PPP, is a derivative of HDLC which is the DERATIVE of SDLC
SDLC insights to half a dozen other modern protocols, SDLC and HDLC and PPP and FrameRelay are lay DATALINK layer protocols,
How do you catergorize it, datalink protocols are PPP protocols
What does this mean exactly,
You and to the bank is PPP no Network Layer Involved, by week 14 why is is not a good idea to put a bank machine on the Internet.
You don’t have to worry about Ordered Delivery theirs only one route
It is stressed it is a Data link protocol,
When you want to learn about protocol you look at the control information that is infront TCP/IP 20 bytes of information in front of every protocol.
He will send us a website with the information to the diagram from this lecture
SDLC + HDLC + PPP and all the things have a
Variable data size – the protocol does not specify the maximum data unit
Ethernet is also a data link protocol it has a maximum variable data size.
If you worked at Scotia bank you would pick the maximum data size, it has versatility you can do what you want with the variable size.
U would say if setting up a bank application down at the bottom of the script would be
MAXDATA : 100
The address 8 bits, 2 bytes long
Lets go through this you ask for 100 bucks from a bank machine it will put the information into the data field, the bank machines surrounds your data with this extra information, a 1 byte
FLAG – 8 bit of information - 01111110
Frame Relay same information it starts with a flag
Why do we need flags, know when we know the message is over.
The reason you need a flag cause SDLC does not have a fixed data size,
Ex: what happends a receiving machines gets a start flag it reads data, onlt when it sees an end flag it knows it has received a complete message.
Start flag and end flag are like book marks between the data.
SDLC will guard against theirs another 6 bits that our not ours, when they all want to send a message the protocols will examines the data, looking for an occurrence of six consecutive ones
While building a frame the data is examined if the software (HDLC) if it ever finds 5 consecutive 1 bits it will stick an artificial zero at the end it will say AH I have a astart frame the computer will then remove the artificial bit and restore the bit, this is called BIT stuffing after 5 consecutive 1’s.
The 1’s are used cause we don’t know the size of the data field
The address is manually applied, one thing to consider, a 1 byte control field,
TCP/IP had 20 bytes of control information, very very inefficient, SDLC 8 bits of control information these 8 bits DETERMINE how SDLC operates, To control 8 bits wonderfully efficiently.
All the protocols we we are going to look at have
THREE FRAME formats its determined by the CONTROL FIELD
This is the first format, theirs a 0 in the control field that means an
information frame is being transmitted, however if if its 1 then a 0 then we are dealing with a
supervisory frame – positive ack, neg ack, and flow control feature
We are doing this with 8 bits instead of 20 bytes like TCP
So we got sending data, error handeling done by the supervisory frame,
A THIRD FRAME
Unnumbered – Used for Network Management Functions
its specially special, Network Management software, theirs number frames with 1 command u can take down and put up
SDLC uses what is called a SLIDING WINDOW (this is the window size), they call this a
Sequence Number
000 – Received Sequence Number
000- Send Sequence Numbers
SDLC can send 7 frames before an acknowledgement is demanded
Totally Reliable, it’s a VERY VERY.
Why 7 frames?
001
010
011
It will senevn frames cause the SN only has 7 frames cause it only has 3 bits,
The seven frames will go out into the internet and the deatination computer will get the 7 frames and then it will do
Error Checking
Under 7 frames CRC on each and every frames
If they are all correct the receiving computer will build a supervisory frame in the reciving computer it will put receive data
111
Function Code
00 means no errors
Supervisors address control and flags
The sending machine sends the other information, once it gets to 7 gets back to zero then starts again
What if their was an error in frame 6, it does CRC error checking.
The receiving computer sends a supervisory frame of a function code of 01 indicating their has been an error, 110.
Supervisory from 11 means stop sending data
Supervisory three things, pos ack, neg ack , and flow control
Whether its an information , supervisory and unnumbered frame, why is it unnumbered, cause they have received sequence number
Information have reveinumber send number
Unnumbered have 5 bits of function code, bring a network down up , reset the machine, 5 bits has 32 different functions, Network Manage Person can do function
Understand unnumbered frams perform network management functions.
Supervisory frames never send data, address control and end flag,
You can send data unnumbered frames, buy your RRSP the NMPerson, here’s a little
The final bit
Pull Final – 1 bit has 2 jobs, depends on which direction the message is moving, with SDLC central computer are called primary units and others primary units, primary units are computers that control the ordered delivery of data
Their can be no collisions in SDLC, think about it,
There is two people and they are side by side and they both ask for $100 and press enter at exactly the same time what will happen
POLLING is used for flow control, hence the name POLL, the bank machine handling SDLC each circuit SDLC will send a POLLING message is a supervisory frame with no data the bit in the middle will be turned on,
It will send it to the new frame ask if it has data pull back and see if it needs pulls the data then it goes to the next machine,
POLLING to each machine, pul indicator primary to secondary
Different if its coming from the secondary unit to the primary unit its called a final indicator bit.
Final frame it know it has received 1 2 3 and there is no more frames, 1 bit with 2 jobs.
Next 5 weeks:
WAN protocol, and Internet protocol, Test 2 WAN protocol questions and Internet specific questions
When you typed router rip
Router RIP- To build something called a Routing Information Table
Two flavours of routing information protocols RIP is the oldest.
RIP V2
Configuring router 1, R1 knows two things, R1 knows about subnet 1 and subnet 2,
R2 knows about S2 S3, R3 S3 S4.
RIP starts up in your router, does something intresting, will send out ever interface it knows and every serial it knows
RIP REQUEST – frame of data – 2 pieces of information, it knows about S1 and S2 and will send it to its neighbour, when R2 gets the rip request will send a rip request, it will say it knows about Subnet3 and Router 3
R1
IP address | Hop Count | Interface
S3 1 S0
*Add*
S4 2 S0
Now R1 knows that R1 is associated with R2 subnet 3
R2
IP address | Hop Count | Interface
S1 1 S1
S4 1 S0
Every 20 seconds when started, biggest problem, every 20 seconds on average it sends a RIP request to its Neighbours.
Another 20 seconds pass so R2 will send everything it knows ^^Addings to RIP: router 1 will *Add*
Second Major problem
IETF webpage, - Specification for maximum Hop count of 15
If you connect 2 routers together it will see that it will be 1hop count, rip will always send it out the fasts, the minimum HOP count.
Next week A FAR BETTAH routing PROTOCOL HA HA HA AHHHHH!
OPEN SORTING PATH is by far a superior protocol, far more complex protocol.
When you type in router RIP its rip version rip, the third crucial failure it cannot understand subnets. RIPv2 does address subnets
Test 2 in week 13
Scummed the test AAAAAAAAAHHHHHHHHHHHHHHHRRRRRRRRHHHHHHHHHH!
In the course outline
2test each worth 25%,
1Q 10%
FE 40%
Test 1 20%
60/3
Question 1
It’s a protocol
SDLC- Synchronous Data link Control Protocol
For the 100$ coming out of your bank accounts, you use SDLC
IBM’s protocol very expensive
OSI changed SDCL to –HDLC-
HDLC is ciscos default datalink protocol, if you understand SDLC you will understand HDLC
This is a data link layer protocol
IETF renamed it to PPP, is a derivative of HDLC which is the DERATIVE of SDLC
SDLC insights to half a dozen other modern protocols, SDLC and HDLC and PPP and FrameRelay are lay DATALINK layer protocols,
How do you catergorize it, datalink protocols are PPP protocols
What does this mean exactly,
You and to the bank is PPP no Network Layer Involved, by week 14 why is is not a good idea to put a bank machine on the Internet.
You don’t have to worry about Ordered Delivery theirs only one route
It is stressed it is a Data link protocol,
When you want to learn about protocol you look at the control information that is infront TCP/IP 20 bytes of information in front of every protocol.
He will send us a website with the information to the diagram from this lecture
SDLC + HDLC + PPP and all the things have a
Variable data size – the protocol does not specify the maximum data unit
Ethernet is also a data link protocol it has a maximum variable data size.
If you worked at Scotia bank you would pick the maximum data size, it has versatility you can do what you want with the variable size.
U would say if setting up a bank application down at the bottom of the script would be
MAXDATA : 100
The address 8 bits, 2 bytes long
Lets go through this you ask for 100 bucks from a bank machine it will put the information into the data field, the bank machines surrounds your data with this extra information, a 1 byte
FLAG – 8 bit of information - 01111110
Frame Relay same information it starts with a flag
Why do we need flags, know when we know the message is over.
The reason you need a flag cause SDLC does not have a fixed data size,
Ex: what happends a receiving machines gets a start flag it reads data, onlt when it sees an end flag it knows it has received a complete message.
Start flag and end flag are like book marks between the data.
SDLC will guard against theirs another 6 bits that our not ours, when they all want to send a message the protocols will examines the data, looking for an occurrence of six consecutive ones
While building a frame the data is examined if the software (HDLC) if it ever finds 5 consecutive 1 bits it will stick an artificial zero at the end it will say AH I have a astart frame the computer will then remove the artificial bit and restore the bit, this is called BIT stuffing after 5 consecutive 1’s.
The 1’s are used cause we don’t know the size of the data field
The address is manually applied, one thing to consider, a 1 byte control field,
TCP/IP had 20 bytes of control information, very very inefficient, SDLC 8 bits of control information these 8 bits DETERMINE how SDLC operates, To control 8 bits wonderfully efficiently.
All the protocols we we are going to look at have
THREE FRAME formats its determined by the CONTROL FIELD
This is the first format, theirs a 0 in the control field that means an
information frame is being transmitted, however if if its 1 then a 0 then we are dealing with a
supervisory frame – positive ack, neg ack, and flow control feature
We are doing this with 8 bits instead of 20 bytes like TCP
So we got sending data, error handeling done by the supervisory frame,
A THIRD FRAME
Unnumbered – Used for Network Management Functions
its specially special, Network Management software, theirs number frames with 1 command u can take down and put up
SDLC uses what is called a SLIDING WINDOW (this is the window size), they call this a
Sequence Number
000 – Received Sequence Number
000- Send Sequence Numbers
SDLC can send 7 frames before an acknowledgement is demanded
Totally Reliable, it’s a VERY VERY.
Why 7 frames?
001
010
011
It will senevn frames cause the SN only has 7 frames cause it only has 3 bits,
The seven frames will go out into the internet and the deatination computer will get the 7 frames and then it will do
Error Checking
Under 7 frames CRC on each and every frames
If they are all correct the receiving computer will build a supervisory frame in the reciving computer it will put receive data
111
Function Code
00 means no errors
Supervisors address control and flags
The sending machine sends the other information, once it gets to 7 gets back to zero then starts again
What if their was an error in frame 6, it does CRC error checking.
The receiving computer sends a supervisory frame of a function code of 01 indicating their has been an error, 110.
Supervisory from 11 means stop sending data
Supervisory three things, pos ack, neg ack , and flow control
Whether its an information , supervisory and unnumbered frame, why is it unnumbered, cause they have received sequence number
Information have reveinumber send number
Unnumbered have 5 bits of function code, bring a network down up , reset the machine, 5 bits has 32 different functions, Network Manage Person can do function
Understand unnumbered frams perform network management functions.
Supervisory frames never send data, address control and end flag,
You can send data unnumbered frames, buy your RRSP the NMPerson, here’s a little
The final bit
Pull Final – 1 bit has 2 jobs, depends on which direction the message is moving, with SDLC central computer are called primary units and others primary units, primary units are computers that control the ordered delivery of data
Their can be no collisions in SDLC, think about it,
There is two people and they are side by side and they both ask for $100 and press enter at exactly the same time what will happen
POLLING is used for flow control, hence the name POLL, the bank machine handling SDLC each circuit SDLC will send a POLLING message is a supervisory frame with no data the bit in the middle will be turned on,
It will send it to the new frame ask if it has data pull back and see if it needs pulls the data then it goes to the next machine,
POLLING to each machine, pul indicator primary to secondary
Different if its coming from the secondary unit to the primary unit its called a final indicator bit.
Final frame it know it has received 1 2 3 and there is no more frames, 1 bit with 2 jobs.
Next 5 weeks:
WAN protocol, and Internet protocol, Test 2 WAN protocol questions and Internet specific questions
When you typed router rip
Router RIP- To build something called a Routing Information Table
Two flavours of routing information protocols RIP is the oldest.
RIP V2
Configuring router 1, R1 knows two things, R1 knows about subnet 1 and subnet 2,
R2 knows about S2 S3, R3 S3 S4.
RIP starts up in your router, does something intresting, will send out ever interface it knows and every serial it knows
RIP REQUEST – frame of data – 2 pieces of information, it knows about S1 and S2 and will send it to its neighbour, when R2 gets the rip request will send a rip request, it will say it knows about Subnet3 and Router 3
R1
IP address | Hop Count | Interface
S3 1 S0
*Add*
S4 2 S0
Now R1 knows that R1 is associated with R2 subnet 3
R2
IP address | Hop Count | Interface
S1 1 S1
S4 1 S0
Every 20 seconds when started, biggest problem, every 20 seconds on average it sends a RIP request to its Neighbours.
Another 20 seconds pass so R2 will send everything it knows ^^Addings to RIP: router 1 will *Add*
Second Major problem
IETF webpage, - Specification for maximum Hop count of 15
If you connect 2 routers together it will see that it will be 1hop count, rip will always send it out the fasts, the minimum HOP count.
Next week A FAR BETTAH routing PROTOCOL HA HA HA AHHHHH!
OPEN SORTING PATH is by far a superior protocol, far more complex protocol.
When you type in router RIP its rip version rip, the third crucial failure it cannot understand subnets. RIPv2 does address subnets
Tuesday, October 30, 2007
OPS435W9
No double quotes the shell will automatically go into file name expansion, this was one problem with the assignment.
An example with this
Echo $bs|grep [^0-9]
New stuff
RCS
Revision Control System
What is RCS?
What is it used for?
What is the revision number of the current Linux kernel 2.6.28….the second number if its odd its development if its 6 it’s a working version.
What does the 28 mean, it tells you the 2.6 version has been 28 times since its release.
Bugs or any functionality that needs to be upgraded.
^^this is what its all about,
These numbers are not being tracked its being done by the RCS system, lets look at how it works,
We are going to be using this for our next assignment 2, this system will keep track of the changes you make all long, this will keep track with revision numbers like the kernel numbers in Linux, this is used when you graduate when you get a job you will work in groups and your working on a utility of some sort this system has to keep track of all the ongoings, and has to allow each member of the group to develop and making changes, and also prevent people outside of the group to not come in and make changes.
Version Management
You can use this program to keep track of data files or anything, all versions are stored as a single file, for instance when you have revisions there is only ONE file, you can have multiple revision in a single file, with RCS you can keep track of it, or you can ask it to what ever revision you want to work with, the system will go back and undo the changes you have done to work with.
Some commands
-rcs
-ci
-co
To initialize rcs you use rcs –i filename
RCS needs a unique director so we have created a directory called RCS
When you initiate files, the rcs will ask you to give a description what the files about the comma v is added to any file that is created in any RCS system this is created to say it’s a RCS file not a regular file, the file we have initiated it does contain the file of the original file, it has created a RCS shell around it
My New Prompt $RCS
-bash: RCS: command not found
My New Prompt $ls RCS/
age,v
My New Prompt $cat RCS/age,v
head ; version number
access; who has access to the file
symbols;
locks; strict;
comment @# @;
desc
@this is my assignment 1 file from OPS435
@
When you do assignment #2 you will have to give ur partner cause we will be only using 2 accounts, once you make this decision the other person will have to have access to the file,
You have to use the check commands to play with the file, you have to check the file in or check the file out, when someone is on it you cant use it.
Ci jj
This checks it into the RCS directory you never go into the jj,v you have to check it out, you can use
Co –l jj
You want to use co –l because then it will be locked, so no one else can use it and only you,
Ci jj
RCS –a command, to give access to the person, you add the name of the user with no space
Rcs –afcrusso age,v
Rlog to see the history of this file
Ex: rlog jj
My New Prompt $RCS
-bash: RCS: command not found
My New Prompt $ls RCS/
age,v
My New Prompt $cat RCS/age,v
head ;
access;
symbols;
locks; strict;
comment @# @;
desc
@this is my assignment 1 file from OPS435
@
You can branch off to different branches, the particular item will tell you which branch the tree is in.
Make more changes
Co –l age.v
There are a number of commands parted of the RCS system
.rlog – history of the command
Not using this semester
.ident – certain keywords
.rcsdiff – different of versions
.rcsmerge – merge files
.rcsclean – get rid of duplicate copies
Another system CBS and has many more functionalities.
And that’s our RCS.
On warning, if you initialize a file with the rcs –I as you know that’s just a shell does not contain the data of the file, if you were to check out the file, because the file does not contain data it will wipe out ur original file if you continue if will put nothing in your original file, do a check in before you do a check out.
When you encounter during the test some of the simple things, one thing that was expected the bonus question
Regular expressions
Find if $1 is an integer
Echo $1 | grep ‘[^0-9]’ || \$1
[ $1 –ge 0 ] 2> /dev/null
Expr $1 / 1
Thedate:
Cal|tail +3|wc –w
Cal|grep –v ‘[a-z]’
An example with this
Echo $bs|grep [^0-9]
New stuff
RCS
Revision Control System
What is RCS?
What is it used for?
What is the revision number of the current Linux kernel 2.6.28….the second number if its odd its development if its 6 it’s a working version.
What does the 28 mean, it tells you the 2.6 version has been 28 times since its release.
Bugs or any functionality that needs to be upgraded.
^^this is what its all about,
These numbers are not being tracked its being done by the RCS system, lets look at how it works,
We are going to be using this for our next assignment 2, this system will keep track of the changes you make all long, this will keep track with revision numbers like the kernel numbers in Linux, this is used when you graduate when you get a job you will work in groups and your working on a utility of some sort this system has to keep track of all the ongoings, and has to allow each member of the group to develop and making changes, and also prevent people outside of the group to not come in and make changes.
Version Management
You can use this program to keep track of data files or anything, all versions are stored as a single file, for instance when you have revisions there is only ONE file, you can have multiple revision in a single file, with RCS you can keep track of it, or you can ask it to what ever revision you want to work with, the system will go back and undo the changes you have done to work with.
Some commands
-rcs
-ci
-co
To initialize rcs you use rcs –i filename
RCS needs a unique director so we have created a directory called RCS
When you initiate files, the rcs will ask you to give a description what the files about the comma v is added to any file that is created in any RCS system this is created to say it’s a RCS file not a regular file, the file we have initiated it does contain the file of the original file, it has created a RCS shell around it
My New Prompt $RCS
-bash: RCS: command not found
My New Prompt $ls RCS/
age,v
My New Prompt $cat RCS/age,v
head ; version number
access; who has access to the file
symbols;
locks; strict;
comment @# @;
desc
@this is my assignment 1 file from OPS435
@
When you do assignment #2 you will have to give ur partner cause we will be only using 2 accounts, once you make this decision the other person will have to have access to the file,
You have to use the check commands to play with the file, you have to check the file in or check the file out, when someone is on it you cant use it.
Ci jj
This checks it into the RCS directory you never go into the jj,v you have to check it out, you can use
Co –l jj
You want to use co –l because then it will be locked, so no one else can use it and only you,
Ci jj
RCS –a command, to give access to the person, you add the name of the user with no space
Rcs –afcrusso age,v
Rlog to see the history of this file
Ex: rlog jj
My New Prompt $RCS
-bash: RCS: command not found
My New Prompt $ls RCS/
age,v
My New Prompt $cat RCS/age,v
head ;
access;
symbols;
locks; strict;
comment @# @;
desc
@this is my assignment 1 file from OPS435
@
You can branch off to different branches, the particular item will tell you which branch the tree is in.
Make more changes
Co –l age.v
There are a number of commands parted of the RCS system
.rlog – history of the command
Not using this semester
.ident – certain keywords
.rcsdiff – different of versions
.rcsmerge – merge files
.rcsclean – get rid of duplicate copies
Another system CBS and has many more functionalities.
And that’s our RCS.
On warning, if you initialize a file with the rcs –I as you know that’s just a shell does not contain the data of the file, if you were to check out the file, because the file does not contain data it will wipe out ur original file if you continue if will put nothing in your original file, do a check in before you do a check out.
When you encounter during the test some of the simple things, one thing that was expected the bonus question
Regular expressions
Find if $1 is an integer
Echo $1 | grep ‘[^0-9]’ || \$1
[ $1 –ge 0 ] 2> /dev/null
Expr $1 / 1
Thedate:
Cal|tail +3|wc –w
Cal|grep –v ‘[a-z]’
Thursday, October 25, 2007
DCN 286 - Information on Ethernet...MORE INFO!
DCN January 26. 2007
Trying to understand how Ethernet work? What is Ethernet?
Go back in history, the island of Hawaii in the Pacific, in the late 60’s the university of Hawaii had a very clever thought, they had some offices on one side of the island and on the other side, they wanted to communicate between these offices, and their was no way for them to do this, they invented a method, which was satellite service, they developed their own little protocol to send messages to each other, they sent the messages to the satellite and it was a source address and a destination address and of course data, if add wanted to send to add four, the messages would be sent to the satellite and rebound it to the computer. Lets say SA = 1 DA=4, Three would receive the message and ignore it and would only go to its destination. Primitive and it worked. This was called Aloha net. They thought to themselves to send a single down through copper wire. There was a group in the 60’s that developed things like mice, but the most important was Ethernet, and the most was Zerox. ThreeCOM manufacturing Ethernet cards, at the same time IBM was inventing token ring, yet today token ring is gone, Ethernet survived and Ethernet is thriving, December of last year Ethernet people put the standards at running Ethernet at 10 billion bits per second, Then the standardized of 100 billion bits per second. Macaffe invented Etherenet, they put in strands of coaxial cable, DataCom cables coaxial and twisted pair cables, Coax has a thick piece of copper surrounded by a insulated matieral (plastic), surround by a weave, amazing thing about coax the copper is thick and can transfer a lot of Hrz, (hrz dead German guy, working in the 18’s with electricity), the number of wave cycles per second is called one Hrz(hertez), a million Hrz means 100 hrz per second, coax cable b.c its nice and thick can theoretical can handle 100, mill hrz. The coax in the tv can handle 600 mil hrtz, Each station takes 600mil hrtz, Back to MacAfee, we invent a little plug that attaches in the coax, in every comp a special hard that will sit in the expansion slot in each computer (THE NIC) the Network Interface Card has logic, try in to visualize the NIC is a separate device, and has simple logic burned into it, and works with your computer, The idea about the cable was SPEED, A NIC using Ethernet would take data, Operating software uses the inturp and inturrpts the cpu and sends the data, INT52 is a well known interrupt and goes through a specific area in ram grabs the data and moves it to a NIC, The Ethernet guys MacAfee used the follow rules: First the Maximum Transition Unit (MTU), 100 protocols Each has a MTU, All protocols take data, and break it in to pieces the maximum transition unit size is going to be 1500bytes, if you wanted to send 1501 bytes, it would resolve in two transmissions, that is just Ethernet, remember this and remember it NEXT SEMISTER. As the same time in the Ethernet guys IBM was inventing token ring, TOKEN RING when they designed it could send 64,000bytes (huge packets of information), we are going to figure out why the groups made these bye decision Ethernet primitive simple protocol survived, and Token ring survived. When ever a int was sent the NIC would build a frame of data, and infront of it there is a Header, Ethernet header very simple while the TCPIP complicated, HDR has DA SA TL Destination Address, Source Address, A one byte fule called either TYPE or LENGTH. Ethernet uses MAC address, All LAN addresses is how many bytes 4 bytes ip and MAC address is 6 bytes, trillion of address, IMPORTANT’ the MAC address is made up of TWO components, NO two MAC address can be the same, Network standards, the IEEE group Institute of Electronic Engineering (A GROUP), OKAY you are company 999, the first three bytes of the 6 byte address is Manufacture ID, They are identical to AHOLA net, Workstation one wants to send data to Workstation three, the NIC would build the bytes and send it to machine two and ignore the address, and send it to three. Ethernet survived and why…Ethernet was simple that’s the answer it was so basically simple that it thrived, probably for the rest of your lives, you will be working with Ethernet. Test 1 DCN386 questions TWO How does Ethernet work…here is three basic principals on how Ethernet is a base band technology meaning only ONE signal can move down the line at one time (broadband sending 100`s television channels) works CS MA CD, Carrier Sense, first logic in the NIC uses carrier sense, it uses INT52, the NIC looks for digital pulses, if it sees pulses it wont send the data, if theirs no pulses and no one is sending zero data (volts) Carrier sense, no carrier zero volts, no one is sending things, it first makes sure nobody else is using the network, the second pillar of Ethernet wisdom is called multiple access, You can easily simply find the computer on the system , the third is the most important, (CSMA CD), it’s a simplistic design, Ethernet strategy the first work station, the first NIC that detects ugly pulses has a job to do it sends out a high frequency jamming signal, the NIC would try to send it again, Ethernets simplistic approach from this collision will wait on a RANDOM number, > DATA >T L > SA > DA, Zerox ThreeCOM started Ethernet, the original ThreeCOM internet message was like DATA . TYPE . SA. DA, what do you think type stands for…it’s a two bite field that represented which higher protocol, Ethernet has never worked alone it is a delivery boy, a delivery of data. Type (a number) sends the frame to another destination reads the data and looks at the type and understands to send the data to TCP data, it can be all sorts of different TYPE, logic when sending data take note of where its from look at the data and note it should be shot of to TCP program. (HUMAN RESOURCES) IEEE our friends did few things, started making standards which allowed different types of local area networks to communicate with each other. The IEEE came up with the standard 802, this started in 1980 in Feb, they said its going to be called 802.3 and token ring 802.5, 802.11 is wireless, one of the changes was the change of TYPE and made it length, why do you need a length field, well what if you were only sending 25 bytes of data that may or might be not be a important, how does the IEEE know what type of data..they borrowed the first two bites the IEEE solved the confusion of the none 802.3. Ex: Three companies Zerox, Digital Dix, the IEEE solved the problem, today they all worktogether,, not important for dcn 286 theirs a extra thing they put on the frame theirs a preamble, its 64 bits long, 101010101010101010101010 alternating ones and zeros. Think about this you’re a NIC that cost 25$ you can send info to each other, what would happen if you were in a bad mood, and u started sending smaller bits, how does this precision they get insync, very simple very basic that works. Primitive 10baseT 10 million bits persecond using base technology over twisted pair cables, think go Cat5 Cable, Lab wed Cat5 and make the cable straight threw and crossover. Beaware of this Cat5 comes int two types UTP and STP, unshielded twisted pair, and shielded twisted pair. Cat 5 6 7 learn to love next wed. READ up to chapter three.
Trying to understand how Ethernet work? What is Ethernet?
Go back in history, the island of Hawaii in the Pacific, in the late 60’s the university of Hawaii had a very clever thought, they had some offices on one side of the island and on the other side, they wanted to communicate between these offices, and their was no way for them to do this, they invented a method, which was satellite service, they developed their own little protocol to send messages to each other, they sent the messages to the satellite and it was a source address and a destination address and of course data, if add wanted to send to add four, the messages would be sent to the satellite and rebound it to the computer. Lets say SA = 1 DA=4, Three would receive the message and ignore it and would only go to its destination. Primitive and it worked. This was called Aloha net. They thought to themselves to send a single down through copper wire. There was a group in the 60’s that developed things like mice, but the most important was Ethernet, and the most was Zerox. ThreeCOM manufacturing Ethernet cards, at the same time IBM was inventing token ring, yet today token ring is gone, Ethernet survived and Ethernet is thriving, December of last year Ethernet people put the standards at running Ethernet at 10 billion bits per second, Then the standardized of 100 billion bits per second. Macaffe invented Etherenet, they put in strands of coaxial cable, DataCom cables coaxial and twisted pair cables, Coax has a thick piece of copper surrounded by a insulated matieral (plastic), surround by a weave, amazing thing about coax the copper is thick and can transfer a lot of Hrz, (hrz dead German guy, working in the 18’s with electricity), the number of wave cycles per second is called one Hrz(hertez), a million Hrz means 100 hrz per second, coax cable b.c its nice and thick can theoretical can handle 100, mill hrz. The coax in the tv can handle 600 mil hrtz, Each station takes 600mil hrtz, Back to MacAfee, we invent a little plug that attaches in the coax, in every comp a special hard that will sit in the expansion slot in each computer (THE NIC) the Network Interface Card has logic, try in to visualize the NIC is a separate device, and has simple logic burned into it, and works with your computer, The idea about the cable was SPEED, A NIC using Ethernet would take data, Operating software uses the inturp and inturrpts the cpu and sends the data, INT52 is a well known interrupt and goes through a specific area in ram grabs the data and moves it to a NIC, The Ethernet guys MacAfee used the follow rules: First the Maximum Transition Unit (MTU), 100 protocols Each has a MTU, All protocols take data, and break it in to pieces the maximum transition unit size is going to be 1500bytes, if you wanted to send 1501 bytes, it would resolve in two transmissions, that is just Ethernet, remember this and remember it NEXT SEMISTER. As the same time in the Ethernet guys IBM was inventing token ring, TOKEN RING when they designed it could send 64,000bytes (huge packets of information), we are going to figure out why the groups made these bye decision Ethernet primitive simple protocol survived, and Token ring survived. When ever a int was sent the NIC would build a frame of data, and infront of it there is a Header, Ethernet header very simple while the TCPIP complicated, HDR has DA SA TL Destination Address, Source Address, A one byte fule called either TYPE or LENGTH. Ethernet uses MAC address, All LAN addresses is how many bytes 4 bytes ip and MAC address is 6 bytes, trillion of address, IMPORTANT’ the MAC address is made up of TWO components, NO two MAC address can be the same, Network standards, the IEEE group Institute of Electronic Engineering (A GROUP), OKAY you are company 999, the first three bytes of the 6 byte address is Manufacture ID, They are identical to AHOLA net, Workstation one wants to send data to Workstation three, the NIC would build the bytes and send it to machine two and ignore the address, and send it to three. Ethernet survived and why…Ethernet was simple that’s the answer it was so basically simple that it thrived, probably for the rest of your lives, you will be working with Ethernet. Test 1 DCN386 questions TWO How does Ethernet work…here is three basic principals on how Ethernet is a base band technology meaning only ONE signal can move down the line at one time (broadband sending 100`s television channels) works CS MA CD, Carrier Sense, first logic in the NIC uses carrier sense, it uses INT52, the NIC looks for digital pulses, if it sees pulses it wont send the data, if theirs no pulses and no one is sending zero data (volts) Carrier sense, no carrier zero volts, no one is sending things, it first makes sure nobody else is using the network, the second pillar of Ethernet wisdom is called multiple access, You can easily simply find the computer on the system , the third is the most important, (CSMA CD), it’s a simplistic design, Ethernet strategy the first work station, the first NIC that detects ugly pulses has a job to do it sends out a high frequency jamming signal, the NIC would try to send it again, Ethernets simplistic approach from this collision will wait on a RANDOM number, > DATA >T L > SA > DA, Zerox ThreeCOM started Ethernet, the original ThreeCOM internet message was like DATA . TYPE . SA. DA, what do you think type stands for…it’s a two bite field that represented which higher protocol, Ethernet has never worked alone it is a delivery boy, a delivery of data. Type (a number) sends the frame to another destination reads the data and looks at the type and understands to send the data to TCP data, it can be all sorts of different TYPE, logic when sending data take note of where its from look at the data and note it should be shot of to TCP program. (HUMAN RESOURCES) IEEE our friends did few things, started making standards which allowed different types of local area networks to communicate with each other. The IEEE came up with the standard 802, this started in 1980 in Feb, they said its going to be called 802.3 and token ring 802.5, 802.11 is wireless, one of the changes was the change of TYPE and made it length, why do you need a length field, well what if you were only sending 25 bytes of data that may or might be not be a important, how does the IEEE know what type of data..they borrowed the first two bites the IEEE solved the confusion of the none 802.3. Ex: Three companies Zerox, Digital Dix, the IEEE solved the problem, today they all worktogether,, not important for dcn 286 theirs a extra thing they put on the frame theirs a preamble, its 64 bits long, 101010101010101010101010 alternating ones and zeros. Think about this you’re a NIC that cost 25$ you can send info to each other, what would happen if you were in a bad mood, and u started sending smaller bits, how does this precision they get insync, very simple very basic that works. Primitive 10baseT 10 million bits persecond using base technology over twisted pair cables, think go Cat5 Cable, Lab wed Cat5 and make the cable straight threw and crossover. Beaware of this Cat5 comes int two types UTP and STP, unshielded twisted pair, and shielded twisted pair. Cat 5 6 7 learn to love next wed. READ up to chapter three.
DCN 286 - Information on TCP....B/C You will be writing Essays On This ALL THE TIME!
What is ip and what does it do, what is ip’s job, Ip’s job is simple is to get our data through the internet as quickly as possible and that all its job is its job is not to make sure your sure data is safe Ip does not care about that and if it looses you’re data oh well, and not their for reliability all it cares about is trying its little best to send your data through the net as quickly as possible, ip runs not only in your computer, but in all the routers in the internet, client and server, all have ip, gets stuff done fast, you’re going to tell in week 14 about the total length (16 bits) it can theoretically take you’re data and put it into pieces 65,535 K the routers hate big packets, so if you accidently sent a big packet it would break it into fragements, if you approach a cisco router CISCOs default is 1500 bytes, you can change the router MTU bigger or smaller (maximum transmission unit) it uses the identification field so all the fragments have unique numbers, the router then takes a fragment offset value and see which position its on, middle first or last fragments so when all the fragments get to destination computer IP will reassemble the fragments in the original , TIME to live is how many hops a packet can go through the network, you can overwrite it depends on you’re OS, if the router can’t go to the destination it will get destroyed , last thing were going to tell him is the IP address, IP addressing 32 bits of total confusion, todays not ip but TCP, Tranfer Control Protocol, essays on TCP for the rest of you’re Seneca carrier, at first glance it looks very simple but very deceptive very complex, TCP provides reliability TCP/IP running on your computer, in the Internet cloud theirs huundred of thousands of routers, and all the routers are interconnected, the routers are also running IP when you pass the IP packet to the router and examines the destionation address. TCP is running in any server you connect to, what are you doing at home maybe you wanna download a picture of Pluto, www.nasa.org, scattered around the would there are DNS they have two database with NAMES AND ADDRESS, when you contact the DNS server send it a name and will return an IP address, TCP is going to provide realiability while you download the picture to do this it is going to use something called a port, a port when talking about TCP is a number a 16 bit number so 65, 535K, IEEE standards organization which came up with a list with internet application, DNS internet application, TELNET, FTP HTTP, anyone who, HTTP port 80, FTP port 21/22, TELNET 23 we are going to use FTP to download the picture of Pluto, the port numbers 0-1000, are reserved port numbers for legitimate internet application called Well known ports, over 1000 free to be used by any computer, Here you go you got the ip from dns and you know nasa, org TCP doesn’t know the address but attached to IP and its going to build a header information, default header size is 20 bytes and its going to start ot build port numbers destination port Destination port is 21, you can send lots of things to nasa.org you can try to telnet to nasa.org but you want to download something so you are using FTP, TCP will generate a random number will be between 1000, 65000, essentially its going to say this to the client machine to the server what your doing is TCP is opening a session between your client and nasa.org, there is now a session being established, to work correctly, when the seassion has been established the two machines can send data with eachother first open a session then send data then end the session, the session to be established though is a little bit complicated, a client machines sends segment to the server and will flip the two numbers around and send them back to you, here is the complicated part, TCP receives confirmation sends a third header switching it again, the two machines, when they are forming a session are negotiating with each other, before they need to send data, two or three things they must know, most important thing is how long does it takes TCP segment to go from here to the network and back again, the client initiates the second sending TCP record number 1 this machines looks at the system clock on the computer and record the time for the request of the session the little fragment goes flying through the network and sends it back and looks at the system clock again and now they know how long the round trip is going to know how long its going to take, lets just say it takes 1 second, but this machine does not know what it is and is the purpose of the third segment, is looks at the system clock, three headers, now both machines understands how long it takes to you’re computer and the server now it know it takes from it to you, other important things are being negotiated when tcp first came out, back when their was 50 computers and the internet tcp used sequence number and acknowledgement number for error checking, if there is no errors its going to send an acknowledgement number for error handling the sequence number in early days, use to start at sequence number 1 then 2,3(Frames) does not happened any , more, early days no hacking, sequence number was a hackers prayer, todays version of tcp, between the negotiation will pick another random number, you got 32 bits, what’s the maximum number 4 bil and change, so ip when its sending the initial request will pick a random number 0 -4bil and will stick it in the sequence number field (init sequence number) it will start counting at five when it gets it and when gets to the server another random number is chosen, to set this session we look at the little 1 bit of information when the client sends the first header its going to turn on the SYN (flag 1) when it sends the reply its going to turn on the ack bit (1) when it sends the third reply its going to turn of the syn(0) and send a reply, you notice tcp full duplex protocol, theirs multiple downloads, so lets see how it transits data, how weird is it? Where going to ftp to send data FTP, is a simple protocol, once the session is established it starts reading in data one byte at a time, when ftp thinks its got enough for one segment it will screen the data 1 byte of a time, and codes the bytes 1, 2, 3(bytes) if you left tcp alone it will leave it in your computer it would literally blow your memory of your computer, TCP says I think its enough data (100) bytes and knows the intial sequence number was 5 now its 105 and its going to do error checking on that 100 bytes, using Checksum an algorithm that makes sure theirs no bit errors and if there is no error bit its going to build the acknowledgement number 106, and turn on the acknowledgement number, then the server goes onto the next 100 bits and acknowledge number is going to go to 205, the data gets send tcp does error checking, the machine will build a twenty byte header and positive acknowledge number 300, if you peer closely of the little 1 bits their was a error, what would the server do? What tcp does is unique, TCP does nothing, TCP was written in such a way, TCP looks at the system clock and record the time, if theirs not a positive ack in 1 sec, tcp will automatically retransmit the packet, TCP will notice that the two packets with the same sequence number and discarded one of them, at the end of the session and all the data is sent it goes through a complex procedure to close down the session and we don’t have to worry about till next semester, Window the third thing the initial size, depending on the OS, link between tcp and the operating software, if your using Windows, windows will direct tcp will have an initial window size of 64K, Linux has much smaller window sizes 2k, the bigger the window size the easier you make the hackers job, when the session is nogiated it’s a initial window size, two tcp start sending data, lets say they start small window size of 2k, tcp will actually monitor the number of errors are their, if tcp ‘thinks’ the network is good today because of no errors either machines can increase the window size, and if even more it will increase, tcp increase and decrease the windows until errors start happening, window size is really how much memory is going to be reserved on each computer, the application determines how much or when to send data, it tells tcp heres enough data, and will turn on the push flag and could receive the blocks of bytes and save it in number, when a tcp receives a packet when its turn on it will saveit and push it into the application, its how much memory in each machine is going to be used, ultimately IP is going to see the packet size, Window size is the amount of memory to save multiple tcp pieces, Urgent Pointer and Urgent bit till next semester, for now all we have to know is TCP header and a big pile of data following the header, lets say for some reason the application wanted you to read a specific data that not right on the front it will turn on the urgent data and will read the password which was 100 bytes in, save till next semester. TCP and IP are mentioned numerous chapters into your computer, write essays in week 14 and put these two topics in test TWO to get some practice.
TCP
Source Port(1001) | Destionation Port (21)
Squence Number (00000101)
Acknowledgement Number
Data Offset| Reserved |URG(1)|ACK(0)|PSH|RST|SYN|FIN | window
Checksum | Urgent Pointer(1)
Options + Padding
VERSION IHL TYPE OF SERVICE TOTAL LENGTH
What is a collusion domain, HUB with ports, you got a HUB the simultaneously the collusion will interfere with all the toerh computer, and the chaos is extened to every machines (CD) and the more machines the more chance of collusions happening, Switches are employeed to reduce the effect of collusions of your network, switches break it up to separate collision domains, SWITCH 5 ports and traditional little network hubs to each port and then attached to networks, no the hubs machines are in a collusion domain but if a collusion hapends here and will have no effect on the other domain, Switches reduce the collisions, everything we put on here is its own little collision domain, today happy networking use a process called micro segmentation, what does that mean, networking guys today have virtually eliminated collision through high quality switches and having one machine on each port on a switch their can be no collisions , micro segmentation imply switches and are all into switches Cut THREW switch does what, when a cut threw switch reads the frame it immediately checks the destination address, will immediately set up a channel source and destination port, if you got a nice safe environment, Seneca college, you use cut threw switches, how ever if the environment is a little shakey, in that environment you use STORE and FORWARD switch that has huge amounts of memory and will read the face and its entirety and store the frame where it does error checking, and if the frame takes it and there is no errors it will send it to its destination,
Does not matter which but it can get to one work station through its port, now we want to talk about subnets, switches are datalink layer devices routers are network layer devices, we are one originations and we sell stuff on the net the switch to the computer and the server, we need to sell stuff on the net so we need to buy a router, we need a domain name, our domain name has a associated ip address 200.1.1.0 (ClassC) we hire a networking switch 200.1.1.254, we got a problem cause were in Toronto and going to Vancouver, to they subnet to create it so they can expand and have their own portion, to create subnets its an easy thing don’t matter what class, you create them the same way you play around with binary numbers,windows create subnets a dumb way, and use a short cut and don’t know when there is a lot of subnets, the correct way is to play with binary numbers, which numbers
Network Address 200.1.1.[0] in control of the 4th octet, to create subnets take the host bits and write them out in binary one rule to be applied to subnets by convention we never use all zeros or ones, so we have two left to indicated subnets 00 01 10 11 so 01 becomes Toronto while 10 becomes Vancouver. [00]000000 to indicate if its Toronto or vancouver
SN
00|000000
01|000001 [65]1*
01|111110 [126]2*7th -2
11|111111
We turn on the host bits and the subnet
255.255.255.192 which is the value of [11]000000
1* the address can be added for example 010000010 and moving the 1 up to the numbers
The last number and the range there for becomes 65 – 126
Vancouver
SN
10|000001[129]
10|111110[190]
NOW WE NEED THREE SUBNET IDS with 001 = T. 010 = V 100=LA
001|00001 [33]
001|11110 [62]
TCP
Source Port(1001) | Destionation Port (21)
Squence Number (00000101)
Acknowledgement Number
Data Offset| Reserved |URG(1)|ACK(0)|PSH|RST|SYN|FIN | window
Checksum | Urgent Pointer(1)
Options + Padding
VERSION IHL TYPE OF SERVICE TOTAL LENGTH
What is a collusion domain, HUB with ports, you got a HUB the simultaneously the collusion will interfere with all the toerh computer, and the chaos is extened to every machines (CD) and the more machines the more chance of collusions happening, Switches are employeed to reduce the effect of collusions of your network, switches break it up to separate collision domains, SWITCH 5 ports and traditional little network hubs to each port and then attached to networks, no the hubs machines are in a collusion domain but if a collusion hapends here and will have no effect on the other domain, Switches reduce the collisions, everything we put on here is its own little collision domain, today happy networking use a process called micro segmentation, what does that mean, networking guys today have virtually eliminated collision through high quality switches and having one machine on each port on a switch their can be no collisions , micro segmentation imply switches and are all into switches Cut THREW switch does what, when a cut threw switch reads the frame it immediately checks the destination address, will immediately set up a channel source and destination port, if you got a nice safe environment, Seneca college, you use cut threw switches, how ever if the environment is a little shakey, in that environment you use STORE and FORWARD switch that has huge amounts of memory and will read the face and its entirety and store the frame where it does error checking, and if the frame takes it and there is no errors it will send it to its destination,
Does not matter which but it can get to one work station through its port, now we want to talk about subnets, switches are datalink layer devices routers are network layer devices, we are one originations and we sell stuff on the net the switch to the computer and the server, we need to sell stuff on the net so we need to buy a router, we need a domain name, our domain name has a associated ip address 200.1.1.0 (ClassC) we hire a networking switch 200.1.1.254, we got a problem cause were in Toronto and going to Vancouver, to they subnet to create it so they can expand and have their own portion, to create subnets its an easy thing don’t matter what class, you create them the same way you play around with binary numbers,windows create subnets a dumb way, and use a short cut and don’t know when there is a lot of subnets, the correct way is to play with binary numbers, which numbers
Network Address 200.1.1.[0] in control of the 4th octet, to create subnets take the host bits and write them out in binary one rule to be applied to subnets by convention we never use all zeros or ones, so we have two left to indicated subnets 00 01 10 11 so 01 becomes Toronto while 10 becomes Vancouver. [00]000000 to indicate if its Toronto or vancouver
SN
00|000000
01|000001 [65]1*
01|111110 [126]2*7th -2
11|111111
We turn on the host bits and the subnet
255.255.255.192 which is the value of [11]000000
1* the address can be added for example 010000010 and moving the 1 up to the numbers
The last number and the range there for becomes 65 – 126
Vancouver
SN
10|000001[129]
10|111110[190]
NOW WE NEED THREE SUBNET IDS with 001 = T. 010 = V 100=LA
001|00001 [33]
001|11110 [62]
Subscribe to:
Posts (Atom)