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What is difference between "Frame-Relay Switch" and "Layer 2 Switch"?

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Nov 28th, 2013
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Dear All


I quite confuse the difference between "Frame-Relay-Switch" and "Layer 2 switch"



Are they a switch?


I assume that


1."Layer 2 switch"  learns MAC-Address  and they forward packet based on MAC address they've learned.


2."Frame Relay switch"   they learn DCLI and forward packet based on DLCI.



As I understand,  A Switch is 10/100/1000 Mbps. It should be faster than Frame Relay Switch. 
Why we still use Frame Relay switch today?



Thanks for comment.

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Jon Marshall Fri, 11/29/2013 - 07:16
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Just to add another perspective to Joseph''s post.


A L2 switch is usually found within a LAN ie. they are used within a building or a campus with multiple buildings for ethernet connectivity.  They do as you say generally provide much more throughput than a frame relay switch.


Frame relay switches are used for WAN connectivity. Here you don't usually have the same throughput in terms of bandwidth simply because it can be a lot more expensive.


You would never, as far as i know use a frame relay switch in a LAN enviornment.  However L2 switches may well be found in MAN environments and more recently ethernet can provide WAN connectivity so you may find L2 switches there as well.


Both switches use L2 addressing as do ATM switches as noted by Joseph. Ethernet uses mac addresses, frame relay DLCIs and ATM VPI/VCIs.


Jon

Richard Burts Fri, 11/29/2013 - 07:32
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A layer 2 switch would be a switch that uses Ethernet and as you observe it uses MAC addresses and with Ethernet might support speeds of 10, 100, or 1000. A Frame Relay switch is for Frame Relay which uses serial links for Wide Area connectivity. The reason that some people still use Frame Relay is that it is better suited for WAN connectivity over long distances than Ethernet.


HTH


Rick

Peter Paluch Fri, 11/29/2013 - 08:42
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In addition to all colleagues' responses, my view on this is that a Layer2 switch is any switch which performs its decisions based on Layer2 addressing information, i.e. that operates on the Data Link Layer of the OSI model and uses this information to forward frames.


Depending on the Data Link Layer technology, a Layer2 switch can be an Ethernet switch, an ATM switch, or a Frame Relay switch. All these are, at least from IP protocol's viewpoint, Data Link Layer technologies utilizing frame switching. Hence, a switch capable of switching any of these frames is a Layer2 switch. A Frame Relay switch would be just a single representative of many possible technologies that use frame switching.


Because, however, the Ethernet technology is strongly prevalent and ordinary users come into contact with Ethernet most of the time, the term of "Layer2 switch" has become strongly associated in colloquial language with an Ethernet switch. An Ethernet switch, however, is also just a single representative of many technologies utilizing frame switching, so in my personal opinion, saying that a "Layer2 switch" is exactly an Ethernet switch is too limiting. A Frame Relay switch is a Frame Relay switch; an Ethernet switch is an Ethernet switch, and both of them are Layer2 switches.


Best regards,

Peter

Leo Laohoo Fri, 11/29/2013 - 16:12
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Golly, folks.  This is like going back to history lessons.  FR switch ... wow.  Haven't seen that since 2005.


Frame Relay is a low speed, low cost point-to-point/point-to-multi-point link.  Compared to current DSL, FR links are more expensive because service providers (SP) are bound by a service level agreement (SLA).  Whether or not SPs follow this SLA is out-of-topic. 


As far as I had any exposures to FR, there was little use of FR switch.  Most FR equipment I've worked with are Nortel DPN and Passport WAN routers.  

Joseph W. Doherty Fri, 11/29/2013 - 07:02
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A "typical" L2 switch means an Ethernet L2 switch.  Frame-relay is also L2, by it's a different L2 technology.  The principle of switches applies to more than just Ethernet, for example there's also ATM switches.


BTW, frame-relays switches don't generally learn DLCIs, they are preconfigured.  (Somewhat similar to pre-configuring static MACs to Ethernet ports.


Frame-relay [edit] is falling out of favor for WAN connectivity.

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