When examining the communications infrastructure and the major problems that are associated with using current technologies we see that the point of new technology is to over come deficiencies of current technologies.
The world is moving at fast pace, processors and applications just keep getting faster and faster, so we look at data communications and how it can improve the movement of information within a networked environment.
This chapter gives the general overview of the emerging technology to meet needs of applications.
Needs for Services
The Past
Development of high-speed inexpensive computers to meet the needs of the average person. This opened a vista to new powerful application. Examples of the applications that may be used are interactive real-time simulations, three dimensional modeling and color images.
The T1/E1 Legacies
1970s & 1980s = 1.5 to 2.048 Mbs
- T1/E1 meet the needs for most user applications
VPN - Share communications channels with other users
Switches - Relay traffic from multiple users.
Frame Relay fast packet service
-Lets the user support error recovery
-bandwidth and demand services
-data applications and some voice applications
-Suppose to solve WAN bottle neck services
MAN IEEE Standard 802.6
-distributed queue dual bus (DQDB) protocol to support integraded networks for multimedia applications
-interconnects LANs accross WANs
Switched Multimegabit Data Service (SMDS)
-Relies on the MAN technologies
-provides public high-speed transport system US and Eurpose
Services - highspeed ata applications that require bursts for high-speed data applications that require bursts of high bandwidth transmission for applications.
Such as, file transfer, CADéCAM, and imaging.
Asynchronous Transfer Mode
- part of B-ISDN solution
- cell relay technology
includes - high speed
- multiplexing and switching services for voice, data and video applications
Cell in ATM and IEEE 802.6 (MAN)
802.6 = basis of SMDS
CELL vs FR
Cell at the CPE a computer or PBX
which can be variable
is - segmented into smaller fixed length units called cells
5 header 48 payload
Supports transmission and reception of voice, video data and other applications
Interests = Large companies that have developed multiple networks to handle transmission schemes.
Why do we prefer cell
Cell is better then variable length frames, which provides the delay to be predictable in fixed length frames with the performance in the network then with variable length frames
-ATM queuing is done inside switch
-Fixed length buffers more easier to manage then variable.
-Cell relay has superior Quality of Service.
Wide spread commercial inception of computer and communication's networks in the 1960`s
1970`s - Communications archietecture was all software
Typically
Physical Layer = hardware
Datalink Layer = software
Late 1970`s early 1980`s
implemented into hardware some of the Data Link functions
Fostered HDLC which would
lead to -Link Access Procedure Balanced (LAPB)
-Link Access Procedure For the D channel (LAPD)
-Chip sets and firmware
Thats all I am going to introduce for now next post will continue Chapter 1, in later chapters Uyless Black goes into detail with every protocol mentioned here and that will be in next post. So don`t be to overwhelmed, I know I was the first time I read half the book.
Little note to me: Ch1 Pg5
Saturday, March 22, 2008
Friday, March 21, 2008
About New Postings
Due to the Hands On Work in my program I will only be posting relevant information on every lecture for my courses.
I will be focusing on, Data Communications,
Book:
Emerging Communication Technology by Uyless Black
that will gradually move to
IP Routing Protocols by Uyless Black.
Any relevant information to courses within the Computer System Technology Diploma will be posted with the Title of the Course Code and Topic, mostly theory.
Note: Future online posting will change.
I will be focusing on, Data Communications,
Book:
Emerging Communication Technology by Uyless Black
that will gradually move to
IP Routing Protocols by Uyless Black.
Any relevant information to courses within the Computer System Technology Diploma will be posted with the Title of the Course Code and Topic, mostly theory.
Note: Future online posting will change.
INT420 - Secure Socket Layer
Encryption on the exam,
When we want to send and encrypt data securly, the basic process
take the original data and an encryption key, random string of
characters, random very large number
take the data and teh encryption key and put them into a encryption alogrithem or program
what you get out of that in encrypted data, in order to read that data
you take the encrpyted data and a decryption key put it through the same algorithem/program,
then you end up with the original data,
Two basic models
symitrical encryption - a shared secret
with semitrical encryption you have a single key, and you use the same key to encrypt and decrypt the data
asymetrical encryption - public/private key pairs
two keys, that are designed to work togeter, a public and a private key, in this encryption you encrypt with one or decrypt with the other, u must use the other part of the pair, en pri / de pub
Client Machine Alice
AB-----
Connected to the Net
----AB
Client Machin Bob
using this semitrical encryption alas would need a copy of the key and bob will need the copy of the same key
Its good cause its fast,
you can generate a new key for every process/
---_FAST SECURE__----
Problem how do they get the copy of the same key, especially over a line, the problem with session key how do you get the key on both sides
in the past, generate it on place and take it from one to the other and install but again thats a 1 kind operation.
Asymtrical alias an encrypted connect4ion for bob, he has the public key B and a private key B the private key never leaves bob,
BOb takes his public key gives it to aliace, she encrypts the data with the public and encryps with the private key,
so the communicatiosn going back to alice are not secure, when we encrypt wioth the private anyone can read it
so its not good coming back in the opposite direction but it does have a purpose,
When he sends it to alice and has the private, what does this prove to us anyone can read what bob is sending, it can only have only come from bob. Because bob only has the private this is called a digital signature, anyone with the public key can read the private key but it must come from that source,
its use for authentication as a signature
Alice can gen4erat her own public/private send it to bob send it and she can use it, heres the problem its slow and alot of work, and somewhat more compicated then it needs to be, in the internet when we want to secure over the wweb we use
SSL ---- secure socet layer, you know this from https
SSL uses all the things that were discussed above, this is how it essentially works
Bob the server alice the client,
in order to facilite encrypted communication, bob needs a public and a private key for bob, now
the admin of bob wneeds a 3rd party company to create a certificate to tell the company this is the company, they take the public keye
they take the public key and send it to CERTIFICATE AUTHORITY, dozens of company's that do this
CERTIFICATE REQUEST, name server e-mail the FQDN all info about the orginations and the computer along with the public key,
the certificate authority preforms sum auth then creats a certificate contains all the info from the certificate request + bob public key then the certificate signs it with their private key, so its digitally signed through the CA.
SSL connection
Alice sends a httpds conn to bob then he says ok then sends the certificate and it contained the public key and the didtal sign of the CA alice reciuves the certificate alices browsers is already wiiht the key of all the private ca's auth, now we accept that public key as coming to bob
BOb has his private key and alice has his public key now alice generates a symettrical key thats only good for this session and encrypts using bob public key, bob is the only way he can use it cause he has a private key
Conenection to his web server his e-mail server it puts the https yellow bar and the pad lock
if you go to Tools page info
You look at the page info and you look at security it tells the identify has been varified by Equifax
View the certificate
In the LAB
Re-install apache to include SSL you need to isntall it into a diff directory you will install OPEN SSL, allows you to generate pub and private keys and request and authority, install apache fresh,
M
M
M
we use to for trust, and the mechinism for a public key then facilitae a session key, then they use that session key
When we want to send and encrypt data securly, the basic process
take the original data and an encryption key, random string of
characters, random very large number
take the data and teh encryption key and put them into a encryption alogrithem or program
what you get out of that in encrypted data, in order to read that data
you take the encrpyted data and a decryption key put it through the same algorithem/program,
then you end up with the original data,
Two basic models
symitrical encryption - a shared secret
with semitrical encryption you have a single key, and you use the same key to encrypt and decrypt the data
asymetrical encryption - public/private key pairs
two keys, that are designed to work togeter, a public and a private key, in this encryption you encrypt with one or decrypt with the other, u must use the other part of the pair, en pri / de pub
Client Machine Alice
AB-----
Connected to the Net
----AB
Client Machin Bob
using this semitrical encryption alas would need a copy of the key and bob will need the copy of the same key
Its good cause its fast,
you can generate a new key for every process/
---_FAST SECURE__----
Problem how do they get the copy of the same key, especially over a line, the problem with session key how do you get the key on both sides
in the past, generate it on place and take it from one to the other and install but again thats a 1 kind operation.
Asymtrical alias an encrypted connect4ion for bob, he has the public key B and a private key B the private key never leaves bob,
BOb takes his public key gives it to aliace, she encrypts the data with the public and encryps with the private key,
so the communicatiosn going back to alice are not secure, when we encrypt wioth the private anyone can read it
so its not good coming back in the opposite direction but it does have a purpose,
When he sends it to alice and has the private, what does this prove to us anyone can read what bob is sending, it can only have only come from bob. Because bob only has the private this is called a digital signature, anyone with the public key can read the private key but it must come from that source,
its use for authentication as a signature
Alice can gen4erat her own public/private send it to bob send it and she can use it, heres the problem its slow and alot of work, and somewhat more compicated then it needs to be, in the internet when we want to secure over the wweb we use
SSL ---- secure socet layer, you know this from https
SSL uses all the things that were discussed above, this is how it essentially works
Bob the server alice the client,
in order to facilite encrypted communication, bob needs a public and a private key for bob, now
the admin of bob wneeds a 3rd party company to create a certificate to tell the company this is the company, they take the public keye
they take the public key and send it to CERTIFICATE AUTHORITY, dozens of company's that do this
CERTIFICATE REQUEST, name server e-mail the FQDN all info about the orginations and the computer along with the public key,
the certificate authority preforms sum auth then creats a certificate contains all the info from the certificate request + bob public key then the certificate signs it with their private key, so its digitally signed through the CA.
SSL connection
Alice sends a httpds conn to bob then he says ok then sends the certificate and it contained the public key and the didtal sign of the CA alice reciuves the certificate alices browsers is already wiiht the key of all the private ca's auth, now we accept that public key as coming to bob
BOb has his private key and alice has his public key now alice generates a symettrical key thats only good for this session and encrypts using bob public key, bob is the only way he can use it cause he has a private key
Conenection to his web server his e-mail server it puts the https yellow bar and the pad lock
if you go to Tools page info
You look at the page info and you look at security it tells the identify has been varified by Equifax
View the certificate
In the LAB
Re-install apache to include SSL you need to isntall it into a diff directory you will install OPEN SSL, allows you to generate pub and private keys and request and authority, install apache fresh,
M
M
M
we use to for trust, and the mechinism for a public key then facilitae a session key, then they use that session key
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