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General Forum: Information Technology | | ATM Switch Vs Ordinary switch | |
| Madhu... thought to post-it but u can find more from NAGENDRA.NET.
K....
Posted by: Mr. Kiran Reddy At: 12, Nov 2003 3:32:23 PM IST
http://www.practicallynetworked.com/networking/bridge_types.htm
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Now, your doubt seems very reasonable to me. I bet even the best of networking professionals will not be able to clearly define and list all the differences between each of these devices(repeater,hub,bridge,switch,router...).
Anyways, coming to your question let me give it a try -
BRIDGE - Imagine a real bridge. Now suppose that persons A & B reside on one side of the bridge and C & D on the other side.
So, if A wants to meet B would you think A would travel all across the bridge to the other side to meet B. (Answer - NO).
A bridging device functions similarly. It learns about various nodes on either side of the bridge and only passes(broadcasts) traffic to the other side ONLY when required.
In other words, a bridge creates separate collision domains and merges broadcast domains while with a switch you can have separate collision as well as separate "configurable" broadcast domains.
I say "configurable" because with a switch you can create zones called VLANS and place only those nodes that you would want to communicate with each other in one brodcast domain. Creation of VLANS cannot be accomplished using a bridge.
There are lot more differences between these two and significant ones among those are -
a) Bridges are used to interconnect different types of networks(For example a wired ethernet segment with a wireless 802.11b/g or a token ring network etc..)
b) You can split the bandwidth amongst the nodes using a switch while it is not easily accomplished using a bridge.
c) A switch is also called a multi-port bridge because a (hardware) bridge is formed between any two ports on a switch depending on the need as determined by the switch's forwarding decision.
d) Switches primarily rely on hardware for intelligence while bridges use software based algorithms to maintain the forwarding tables.
e) Bridges mostly just use one type of mechanism for switching the frames i.e., "Store and Forward", in which the bridge has to wait until it recieves the complete frame and check for errors before it could make the forwarding decision while a switch uses "Store & Fwd", "Cut-Through" (waits until it receives first 64K bytes and checks for errors instead of waiting for the entire frame) & "Fast Forward"(no wait & no error checking) mechanisms.
Few more points -
+ To qualify a switch as a "layer 3" switch, it should be capable of doing ISL trunking to "route" between VLANS using the tag info associated to the frame.
+ Repeaters & Hubs are dumb devices. The former amplifies a signal alongwith noise while the latter is just a distribution point with zero intelligence.
Hmmn..that turned out to be a long one..hope that helps to an extent.
Thx.
-Nagendra
nagendra.net
Posted by: Mr. Nagendra Reddy At: 11, Nov 2003 8:06:30 AM IST
Thank You U S E L E S S gaaru ... for spending ur valuable time in giving this DEFINATIONS. But I asked for diff's bet' a bridge & switch. No probs... 'll consider UR VALUABLE SUGGESSION & 'll try 2 look into the so called N/W DIC ...
ThanQ
Posted by: Mrs. MadhaviReddy Madhu At: 10, Nov 2003 3:10:34 PM IST
Bridge
*******
Bridges (sometimes called "Transparent bridges") work at OSI model Layer 2. This means they don't know anything about protocols, but just forward data depending on the destination address in the data packet. This address is not the IP address, but the MAC (Media Access Control) address that is unique to each network adapter card.
With a Bridge, all your computers are in the same network subnet, so you don't have to worry about not being able to communicate between computers or share an Internet connection. DHCP servers will work fine across Bridges, or if you assign your own IP addresses, you'll use the same first 3 "octets" of the IP address
However, the only data that is allowed to cross the bridge is data that is being sent to a valid address on the other side of the bridge. No valid address, no data across the bridge. Bridges don't require programming. They learn the addresses of the computers connected to them by listening to the data flowing through them.
Bridges are very useful for joining networks made of different media types together into larger networks, and keeping network segments free of data that doesn't belong in a particular segment.
Switches
**********
Switches are the same thing as Bridges, but usually have multiple ports with the same "flavor" connection Switches can be used in heavily loaded networks to isolate data flow and improve performance. In a switch, data between two lightly used computers will be isolated from data intended for a heavily used server, for example. Or in the opposite case, in "auto sensing" switches that allow mixing of 10 and 100Mbps connections, the slower 10Mbps transfer won't slow down the faster 100Mbps flow.
Although switch prices are dropping so that there is very little difference from hub prices, most home users get very little, if any, advantage from switches, even when sharing "broadband" Internet connections. "Broadband" connections for most users are in the 1-2Mbps range, far below even 10Mbps speeds. Since you share that bandwidth, you can see that your speedy 100BaseT connection isn't even breaking a sweat when you're using the Internet.if computer 1 talks to computer 3, computer 2 hears nothing.
On high-traffic networks, this means downloads & uploads go a little
faster for everyone. On low-traffic networks (home networks) users
typically don't notice a difference.
Router
*******
Routers forward data packets from one place to another, too! However routers are OSI model Layer 3 devices, and forward data depending on the Network address, not the Hardware (MAC) address. For TCP/IP networks, this means the IP address of the network interface.
Routers isolate each LAN into a separate subnet, so each network adapter's IP address will have a different third "octet" They are necessary in large networks because the TCP/IP addressing scheme allows only 254 addresses per (Class C) network segment.
Routers, like bridges, provide bandwidth control by keeping data out of subnets where it doesn't belong. However, routers need to be set up before they can get going, although once set up, they can communicate with other routers and learn the way to parts of a network that are added after a router is initially configured.
plug some computers into this, and it'll use port forwarding,
IP masquerading, and NAT to allow your computers to share an IP address
and connect to the internet. Cheap routers use HUB technology, good
routers use SWITCH technology.
HUB:
----
plug some computers into this, and all traffic is shared. In
other words, if computer 1 talks to computer 3, computer 2 will also
hear what computer 1 said. Usually computer 2 just discards traffic
not meant for it, but it does tend to burden your network.
You want a router with a few ports/jacks on it. Be sure it says "NAT"
on the box. If it also says "firewall" on the box, lucky you.
A Switch is a multiport-bridge, then they have identical function.
keeping it simple, yes the two operate at the same level of the OSI model.
They both go to layer 2 and are concerned with Mac address of devices so the can logical segment networks.
This allows multiple devices to talk to each other.
As opposed to a hub which takes in something from one port and repeats to all, the bridge takes in on one and passes only to the relevant segment based on its mac address table,
The thing thats confusing is that you do have layer 3 switches , switches which do operate at a higher layer in the OSI model and vendors call them switches, and will also call their layer 2 devices switches which is even more confusing.
Hope I didnt confuse you enev more
still u hav doubt better to buy one
"NET WORK DICTIONARY" available in any market good luck
Posted by: Mr. useless At: 10, Nov 2003 2:32:19 PM IST
Hi All!
ThanQ 4 the valuable info. After checking this part of disc' got some more doubts ...
" i.e, a router routes packets and a switch just switches those packets...as simple as that. " ---) Could anyone lemme know abt bridge & whatz the diff bet' bridge & Switch? Sry 4 the delay in posting the reply ... :)
Hv a nice time
Madhu
Posted by: Mrs. MadhaviReddy Madhu At: 10, Nov 2003 12:55:54 PM IST
cud let us know whats happening here ! with the site!! what exactly this liks is for??
Posted by: Mr. Kiran Reddy At: 8, Nov 2003 7:46:13 AM IST
Lemme try again..But just in case it doesn't work try copying just the URl to your browser's location box
URL - http://nagendra.net/FAQ/faq.php?lang=en&display=faq&onlynewfaq=0&catnr=9&nr=95&prog=NW
(a href="http://nagendra.net/FAQ/faq.php?lang=en&display=faq&onlynewfaq=0&catnr=9&nr=95&prog=NW")Click here and try(/a)
Posted by: Mr. Nagendra Reddy At: 8, Nov 2003 2:38:33 AM IST
(Link= "http://nagendra.net/FAQ/faq.php?lang=en&display=faq&onlynewfaq=0&catnr=9&nr=95&prog=NW")FAQ
Posted by: Mr. Nagendra Reddy At: 8, Nov 2003 2:34:36 AM IST
QoS is a small term with a whole lot of meaning and it really depends on where and how exactly you would like to use it.
To get started follow, <a href="http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/qos.htm">Intro to QOS</a>
Thx.
- <a href="http://www.nagendra.net">Nagendra</a>
Posted by: Mr. Nagendra Reddy At: 7, Nov 2003 12:10:42 PM IST
QoS is a small term with a whole lot of meaning and it really depends on where and how exactly you would like to use it.
To get started follow, <a href=http://www.cisco.com/univercd/cc/td/doc/cisintwk/ito_doc/qos.htm>Intro to QOS</a>
Thx.
- <a href=http://www.nagendra.net>Nagendra</a>
Posted by: Mr. Nagendra Reddy At: 7, Nov 2003 12:07:47 PM IST
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