01-25-2007 11:46 PM - edited 03-05-2019 02:00 PM
Hi,
Can any clear me what is the clear cut difference between switch and bridge???
Rgs
01-26-2007 12:23 AM
Hi!
Good Day! Here is a basic comparison between a switch and a bridge.
Bridge
Filtering Decisions - Software based
STP - Single instance
No. of Ports - More
Forwards Layer 2 Broadcast - Yes
Switch
Filtering Decisions - hardware based (ASIC chips)
STP - Multiple instances
No. of Ports - Less
Forwards Layer 2 Broadcast - Yes
Learning MAC address -Both examines source address of each frame received
Forwarding Decision -Both are based on layer 2 addresses
HTH!
Regards,
Albert
01-26-2007 11:16 PM
Hi
Just to point out the bridge will have less ports compared to switch.
Thanks
Mahmood
01-27-2007 12:02 AM
As wqs said:
A bridge USUALLY has less ports then a switch (but not always)
All the details said above are true, but might be lacking the mention of the (obvious) outcome of one:
Hardware vs software
Bridge is software based switching
Switch is hardware based switching
This means that briges are not as fast as switches.
(If this helps, please rate)
01-27-2007 06:05 AM
In basic operation, a switch *IS* a bridge.
They both break up collision domains, operate at layer two, build their forwarding tables the same way ....
Where the definations start to diverge is in higher functionality.
Switches originally were promoted to be (virtual) "bandwidth multipliers"; a HUB uses shared bandwidth / collision domain ... exactly ONE host could talk at any given time (sucessfully ... two or more caused a collision).
When switches were introduced (Kalpana, later bought by Cisco) their big selling point was that multiple pairs of hosts could talk at the same time, each pair on its own collision domain / circuit / bandwidth, with the general effect being that instead of 10 Mbps of bandwidth shared by all hosts (on a HUB), you could now support (total ports / 2 * 10Mbps) of bandwidth (on a switch).
Additional functionality was added later; things like broadcast control, multicast control, VLANs, multi-instance Spanning-Tree (some switches still only support one STP instance), VTP (Cisco proprietary), etc.
For the sake of general discussion these days, you will usually see "bridges" used to convert the media (i.e., fiber-copper, Ethernet - Serial, and, for the old timers, Translational Bridges ... Ethernet - Token Ring) and switches used for connecting collections of hosts.
Again, pretty much anything you can say about how a bridge operates at a basic level can be said about a switch (breaks collision domains, propagates broadcast/multicasts, Layer 2 device ...).
Bridges these days will tend to have only a few interfaces, and are likely to have special functionality (like a wireless bridge).
Switches are also the only realistic way to provide full-duplex operation on Ethernet. Hubs cannot support half-duplex.
It's better to not really talk about bridges as a device, but as a function. You can turn any Cisco router into a bridge with a couple commands.
So, to directly answer your question: at the level of basic operation, there is NO difference between a switch and a bridge.
Above the "basic operation" level, the multiplication of potential caveats (vendor, generation, purpose, price range ...) makes it, at best, very difficult to describe all the possible differences in the space provided.
Hope this helps ...
Good Luck
Scott
01-29-2007 04:19 PM
Sorry to make you have to go to another webpage to do some reading, but this should sum it up for you:
Good Luck!!!
Steve Quayle
01-30-2007 05:31 AM
Along with all the fantastic responses in this thread, you'll also sometimes hear a switch referred to as a multi-port bridge, Or a smart-bridge.
It's 200000% enhancement of a 802.3 legacy bridge.
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