Network Communication Architecture

Network Communication Architecture
and Protocols
A network architecture is a blueprint of the complete computer communication
network, which provides a framework and technology foundation for
designing, building and managing a communication network. It typically has
a layered structure. Layering is a modern network design principle which
divides the communication tasks into a number of smaller parts, each part
accomplishing a particular sub-task and interacting with the other parts in a
small number of well-defined ways. Layering allows the parts of a communication
to be designed and tested without a combinatorial explosion of cases,
keeping each design relatively simple.
If a network architecture is open, no single vendor owns the technology and
controls its definition and development. Anyone is free to design hardware
and software based on the network architecture. The TCP/IP network architecture,
which the Internet is based on, is such a open network architecture
and it is adopted as a worldwide network standard and widely deployed in
local area network (LAN), wide area network (WAN), small and large enterprises,
and last but not the least, the Internet.
Open Systems Interconnection (OSI) network architecture, developed by
International Organization for Standardization, is an open standard for communication
in the network across different equipment and applications by
different vendors. Though not widely deployed, the OSI 7 layer model is
considered the primary network architectural model for inter-computing and
inter-networking communications.
In addition to the OSI network architecture model, there exist other network
architecture models by many vendors, such as IBM SNA (Systems Network
Architecture), Digital Equipment Corporation (DEC; now part of HP) DNA
(Digital Network Architecture), Apple computer’s AppleTalk, and Novell’s
NetWare. Actually, the TCP/IP architecture does not exactly match the OSI
model. Unfortunately, there is no universal agreement regarding how to describe
TCP/IP with a layered model. It is generally agreed that TCP/IP has
fewer levels (from three to five layers) than the seven layers of the OSI
model.
Network architecture provides only a conceptual framework for communications
between computers. The model itself does not provide specific methods
of communication. Actual communication is defined by various communication
protocols.

Network Protocols

Understanding Network Protocols 

Introduction
A protocol is a standard by which communication takes place between network devices.
The following white paper attempts to explain in the simplest terms the protocols used by
your Iomega network device.
TCP/IP
Transmission Control Protocol/Internet Protocol. TCP/IP is one of the core network
protocols on top of which most other protocols are built. TCP watches network traffic to
detect problems and ensure that data is safely transfered between network devices.
UDP
User Datagram Protocol (also Universal Datagram Protocol). Controls traffic between
network devices, but does not attempt any error correction. It is used for protocols
where speed is more important than accuracy or error correction is handled by the client
software.
SMB/CIFS
Server Message Block/Common Internet File System. SMB is the File transfer protocol
commonly used by Windows computers. Mac OS X and Linux/UNIX now commonly include
an implementation of SMB known as Samba. This protocol uses TCP port 445.
AFP
Apple Filing Protocol. AFP is the file transfer protocol commonly used by Macintosh
computers. This protocol is preferred for Mac transfers since it supports Unicode file
names, resource forks, and other Mac OS specific attributes. This protocol uses TCP ports
548 and/or 427.
NFS
Network File System. NFS is the file transfer protocol commonly used by UNIX/Linux
computers. Due to its UNIX roots, Mac OS X also supports NFS. This protocol uses TCP
port 1025.
HTTPS
Hypertext Transfer Protocol Secure. This protocol is most commonly used for websites and
combines HTTP (see below) transfers with SSL or TLS encryption. Iomega’s remote access
features relies on HTTPS to transfer file lists, downloads, and uploads securely accross
the Internet. The StorCenter ix-Series will also use HTTPS for its web-base configuration
if security is enabled. HTTPS requires a certificate that verifies that the server operator
is who they claim to be. Most web browsers will issue a warning if the HTTPS server’s
certificate cannot be verified. Remote Access users can receive a HTTPS certificate for a
nominal fee. HTTPS (Iomega Remote Access) typically uses TCP port 443.

 FTP
File Transfer Protocol. FTP is a common Internet protocol used for file transfers. Although
FTP is a very common protocol, it still may require special client software in some
situations. For example, the Mac OS X finder supports FTP, but is Read-Only—You will need
special software to use FTP to upload files. This protocol uses TCP port 21.
BitTorrent
BitTorrent is a common peer-to-peer (P2P) file sharing protocol
used on the Internet. Torrents require special software clients
such as the software built-in to the StorCenter ix-Series. This
file sharing method requires .torrent files that are downloaded
from a torrent tracker — a special server that tracks which peers
are sharing a file. The torrent tracker does not actually host a copy of the files that are
being shared. Each peer shares portions of the torrent once it has been downloaded. File
transfer rates increase as more peers participate in the download. This protocol uses TCP
ports 6881-6999; however, many Internet Service Providers (ISPs) throttle traffic on these
ports. Some torrent trackers require that you use a port in the 49152-65535 (unassigned)
range.
HTTP
Hypertext Transfer Protocol. This is the protocol used for most web traffic. Your iomega
network device uses either this protocol or HTTPS (see above) to host the configuration
interface. It will not allow you to host other websites on the device. This protocol usually
uses TCP port 80, but may use 8008, 8080, 16080, etc.
Bluetooth
Bluetooth is a wireless transfer protocol that is used to transfer small
files such as calendars, photos, and contacts over short distances
(using OBEX or Object Exchange Protocol). It is also used to control
devices such as mice wirelessly.
NTP
Network Time Protocol. NTP synchronizes the time between a client and a time server.
This protocol uses UDP port 123.
SMTP
Simple Mail Transfer Protocol. SMTP is a simple email protocol. SMTP is usually only used
for outbound emails such as email notifications sent by your iomega network device. By
default, this protocol uses UDP port 123.

UPnP
Universal Plug-and-Play. UPnP is a set of peer-to-peer network protocols that assist
with the discovery and control of network devices. Iomega network devices use
UPnP to automatically configure network routers for port forwarding and serve
multimedia files. DLNA and Microsoft Rally (see below) are both based on UPnP.
DLNA
Digital Living Network Alliance. DLNA is not technically a protocol, but is a
series of guidelines that define protocols, etc. necessary for network devices
to seamlessly share media files, such as movies, photos, and music. Your
Iomega network device uses DLNA for its media server. DLNA is based on
UPnP (see above).
DAAP/iTunes
Digital Audio Access Protocol. DAAP is a media sharing protocol developed by Apple for
its iTunes software. DAAP uses Bonjour (see below) to announce and discover media files.
This protocol uses TCP port 3689 by default.
Bonjour
Bonjour (formerly known as Rendezvous) is Apple’s implementation of Zeroconf which is
used to discover network resources. Bonjour announces your Iomega network device’s
abilities as a file server, iTunes media server, and print server to client computers. This
protocol uses UDP port 5353.
Windows Rally
Rally is used to discover network resources. Rally announces your Iomega network
device’s abilities as a file server, media server, and print server to client computers. Rally
is based on UPnP.
SNMP
Simple Network Management Protocol. SNMP is used to manage diverse network
resources using a single interface. StorCenter ix-Series servers can be configured using
SNMP client software. This protocol uses UDP port 161.

RJ45 Wiring Standard

TIA/EIA-568-A, T-568B RJ45 Wiring Standard For wiring straight-through and cross-over RJ-45 cables RJ-45 conductor data cable contains 4 pairs of wires each consists of a solid colored wire and a strip of the same color. There are two wiring standards for RJ-45 wiring: T-568A and T-568B. Although there are 4 pairs of wires, 10BaseT/100BaseT Ethernet uses only 2 pairs: Orange and Green. The other two colors (blue and brown) may be used for a second Ethernet line or for phone connections. The two wiring standards are used to create a cross-over cable (T-568A on one end, and T-568B on the other end), or a straight-through cable (T-568B or T-568A on both ends). To create a straight-through cable, you'll have to use either T-568A or T-568B on both ends of the cable. The diagram depicted on the left and right shows clip of the RJ-45 connector down. To create a cross-over cable, you'll wire T-568A on one end and T-568B on the other end of the cable. The straight-through cables are used when connecting Data Terminating Equipment (DTE) to Data Communications Equipment (DCE), such as computers and routers to modems (gateways) or hubs (Ethernet Switches). The cross-over cables are used when connecting DTE to DTE, or DCE to DCE equipment; such as computer to computer, computer to router; or gateway to hub connections. The DTE equipment terminates the signal, while DCE equipment do not. More on straight-through and cross-over connections The RJ45 data cables we use to connect computers to a Ethernet switch is straight-through cables. As noted above, the RJ45 cable uses only 2-pairs of wires: Orange (pins 1 & 2) and Green (pins 3 & 6). Pins 4, 5 (Blue) and 7, 8 (Brown) are NOT used. Straight-through cable, as its name suggests, connects pin 1 to pin 1, pin 2 to pin 2, pin 3 to pin 3, and pin 6 to pin 6. Cross-over cables are used to connect TX+ to RX+, and TX- to RX-, which connects pin 1 to pin 3, pin 2 to pin 6, pin 3 to pin 1 and pin 6 to pin 2. The unused pins are generally connected straight-through in both straight-through and cross-over cables. To network two computers without a hub, a cross-over cable is used. Cross-over cable is also used to connect a router to a computer, or ethernet switch (hub) to another ethernet switch without an uplink. Most ethernet switches today provide an uplink port, which prevents a use of cross-over cable to daisy chain another ethernet switch. Straight-through cables are used to connect a computer to an ethernet switch, or a router to an ethernet switch. Pin Number Designations There are pin number designations for each color in T-568B and T-568A.                  T-568B                         T-568A        --------------------------      ------------------------ Pin    Color             Pin Name      Color           Pin Name ---    -------------     --------      -------------   --------  1     Orange Stripe     Tx+           Green Stripe    Rx+  2     Orange            Tx-           Green           Rx-  3     Green Stripe      Rx+           Orange Stripe   Tx+  4     Blue              Not Used      Blue            Not Used  5     Blue Stripe       Not Used      Blue Stripe     Not Used  6     Green             Rx-           Orange          Tx-  7     Brown Stripe      Not Used      Brown Stripe    Not Used  8     Brown             Not Used      Brown           Not Used

RJ45 Color-Coded Scheme RJ45 cables have 8 color-coded wires, and the plugs have 8 pins and conductors. Eight wires are used as 4 pairs, each representing positive and negative polarity. The most commonly used wiring standard for 100baseT is T-586B stanrard described above. Prior to EIA 568A and 568B standards, the color-coded scheme was used to wire RJ45 cables. The table below depicts pin and color schemes used in traditional and standardized setup. Pin Colored Scheme T-568B (Common) T-568A 1 Blue Orange Stripe Green Stripe 2 Orange Orange Green 3 Black Green Stripe Orange Stripe 4 Red Blue Blue 5 Green Blue Stripe Blue Stripe 6 Yellow Green Orange 7 Brown Brown Stripe Brown Stripe 8 White (or Grey) Brown Brown

RJ-45 Wiring FAQ 1. What are T-568A and T-568B wiring standards, and how are they different? T-568A and T-568B are the two wiring standards for RJ-45 connector data cable specified by TIA/EIA-568-A wiring standards document. The difference between the two is the position of the orange and green wire pairs. It is preferable to wire to T-568B standards if there is no pre-existing pattern used within a building. 2. What is RJ stands for? RJ stands for Registered Jacks. These are used in telephone and data jack wiring registered with FCC. RJ-11 is a 6-position, 4-conductor jack used in telephone wiring, and RJ-45 is a 8-position, 8-conductor jack used in 10BaseT and 100BaseT ethernet wiring. 3. What is the Category Rating System? Electronic Industries Association (EIA) developed the TIA/EIA-568-A standard, which specifies wiring and performance standards for Unshielded Twisted Pair (UTP) cabling. Category Rating System specifies the definition of performance categories for 100 ohm UTP cabling system. Category 3 specifies the twisted pair cable and connecting hardware that can support transmission frequency up to 16MHz, and data rates up to 10Mbps. This is primarily used in telephone wiring. Category 4 specifies cables and connectors that supports up to 20MHz and data rates up to 16Mbps. With introduction of category 5, this is a rarely used category. Category 5 specifies cables and connectors that supports up to 100MHz and data rates up to 100Mbps. With 100BaseT Ethernet today, Category 5 is a widely used cabling system that matches todays high-speed data requirements. Category TIA/EIA Standard Description Cat 1 None POTS, ISDN and doorbell wiring Cat 2 None 4 Mbps token ring networks Cat 3 TIA/EIA 568-B 10 Mbps Ethernet - frequency up to 16MHz Cat 4 None 16 Mbps token ring networks - frequency up to 20MHz Cat 5 None 100 Mbps Ethernet - frequency up to 100 MHz Not suitable for GigE (1000BaseT) Cat 5e TIA/EIA 568-B 100 Mbps & GigE Ethernet - frequency up to 100 MHz Cat 6 TIA/EIA 568-B 2x Performance of Cat 5 & 5e - frequency up to 250 MHz Cat 6a None Future specification for 10Gbps application Cat 7 ISO/IEC 11801 Class F Designed for transmission at frequencies up to 600 MHz 4. What is UTP Cable? UTP stands for Unshielded Twisted Pair. It is the cabling system with one or more pairs of twisted insulated copper wires contained in a single sheath. It is the most widely used cabling system in telecommunications and data communications environment today.

Ethernet Cable - Color Coding Diagram

Ethernet Cable - Color Coding Diagram

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The information listed here is to assist Network Administrators in the color coding of Ethernet cables. Please be aware that modifying Ethernet cables improperly may cause loss of network connectivity. Use this information at your own risk, and insure all connectors and cables are modified in accordance with standards. The Internet Centre and its affiliates cannot be held liable for the use of this information in whole or in part. T-568A Straight-Through Ethernet Cable The TIA/EIA 568-A standard which was ratified in 1995, was replaced by the TIA/EIA 568-B standard in 2002 and has been updated since. Both standards define the T-568A and T-568B pin-outs for using Unshielded Twisted Pair cable and RJ-45 connectors for Ethernet connectivity. The standards and pin-out specification appear to be related and interchangeable, but are not the same and should not be used interchangeably. T-568B Straight-Through Ethernet Cable Both the T-568A and the T-568B standard Straight-Through cables are used most often as patch cords for your Ethernet connections. If you require a cable to connect two Ethernet devices directly together without a hub or when you connect two hubs together, you will need to use a Crossover cable instead. RJ-45 Crossover Ethernet Cable A good way of remembering how to wire a Crossover Ethernet cable is to wire one end using the T-568A standard and the other end using the T-568B standard. Another way of remembering the color coding is to simply switch the Green set of wires in place with the Orange set of wires. Specifically, switch the solid Green (G) with the solid Orange, and switch the green/white with the orange/white. Ethernet Cable Instructions: Pull the cable off the reel to the desired length and cut. If you are pulling cables through holes, its easier to attach the RJ-45 plugs after the cable is pulled. The total length of wire segments between a PC and a hub or between two PC's cannot exceed 100 Meters (328 feet) for 100BASE-TX and 300 Meters for 10BASE-T. Start on one end and strip the cable jacket off (about 1") using a stripper or a knife. Be extra careful not to nick the wires, otherwise you will need to start over. Spread, untwist the pairs, and arrange the wires in the order of the desired cable end. Flatten the end between your thumb and forefinger. Trim the ends of the wires so they are even with one another, leaving only 1/2" in wire length. If it is longer than 1/2" it will be out-of-spec and susceptible to crosstalk. Flatten and insure there are no spaces between wires. Hold the RJ-45 plug with the clip facing down or away from you. Push the wires firmly into the plug. Inspect each wire is flat even at the front of the plug. Check the order of the wires. Double check again. Check that the jacket is fitted right against the stop of the plug. Carefully hold the wire and firmly crimp the RJ-45 with the crimper. Check the color orientation, check that the crimped connection is not about to come apart, and check to see if the wires are flat against the front of the plug. If even one of these are incorrect, you will have to start over. Test the Ethernet cable. Ethernet Cable Tips: A straight-thru cable has identical ends. A crossover cable has different ends. A straight-thru is used as a patch cord in Ethernet connections. A crossover is used to connect two Ethernet devices without a hub or for connecting two hubs. A crossover has one end with the Orange set of wires switched with the Green set. Odd numbered pins are always striped, even numbered pins are always solid colored. Looking at the RJ-45 with the clip facing away from you, Brown is always on the right, and pin 1 is on the left. No more than 1/2" of the Ethernet cable should be untwisted otherwise it will be susceptible to crosstalk. Do not deform, do not bend, do not stretch, do not staple, do not run parallel with power cables, and do not run Ethernet cables near noise inducing components. Basic Theory: By looking at a T-568A UTP Ethernet straight-thru cable and an Ethernet crossover cable with a T-568B end, we see that the TX (transmitter) pins are connected to the corresponding RX (receiver) pins, plus to plus and minus to minus. You can also see that both the blue and brown wire pairs on pins 4, 5, 7, and 8 are not used in either standard. What you may not realize is that, these same pins 4, 5, 7, and 8 are not used or required in 100BASE-TX as well. So why bother using these wires, well for one thing its simply easier to make a connection with all the wires grouped together. Otherwise you'll be spending time trying to fit those tiny little wires into each of the corresponding holes in the RJ-45 connector.