On Sun, Dec 6, 2009 at 11:54, thad <thad.mail...@gmail.com> wrote: > Is fiber cable still an expensive solution?
I don't think so. Actually it's the simplest solution: connect two switches by fiber. Most switches have options for fiber modules. > > > On Fri, Nov 27, 2009 at 8:32 AM, fooler mail <fooler.m...@gmail.com> wrote: >> On Thu, Nov 26, 2009 at 4:20 PM, plug bert <plugb...@yahoo.com> wrote: >>> Hi peeps, >>> >>> Can one use a layer 2 switch to extend ethernet over 100 feet? >>> >>> Ganito kasi: we are planning to get a new office unit, and from the looks >>> of it the cabling will >>> definitely be more than 100 feet. We plan to install around 10 cables in >>> all. >>> >>> >>> Can we just break up each cable, each representing a different subnet, >>> then use a multiport >>> switch, set up a layer 2 VLAN with two ports for each subnet, then connect >>> the two >>> segments to those ports? >> >> hi, >> >> you are talking two different things here - ethernet cable length >> (layer 1 or physical layer) and vlan (layer 2 or data-link layer)... >> >> for layer 1... the length of your ethernet depends on the IEEE 802.3 >> specification that you are going to use... >> >> below are some examples of IEEE 802.3 specifications: >> >> IEEE 802.3 (10base5) - 10 mbps baseband 500 meters coax cable length >> IEEE 802.3a (10base2) - 10 mbps baseband 185 meters coax cable length >> IEEE 802.3i (10baseT) - 10 mbps baseband 100 meters UTP cable length >> IEEE 802.3u >> (100baseTX) - 100 mbps baseband 100 meters UTP cable length >> (100baseSX) - 100 mbps baseband 300 meters multimode opticla fiber >> cable length >> (100baseFX) - 100 mbps baseband 2 kilometers multimode optical >> fiber cable length >> IEEE 802.3ab (1000baseT) - 1000 mbps baseband 100 meters UTP cable length >> >> take note that the metric used here are meters and not feet as what >> you mentioned above... >> >> since you didnt mention what kind of switch you have... ill discuss it >> here so that you can design what is best for your setup... >> >> there are two kinds of hub: >> >> 1. passive hub >> 2. active hub >> >> assuming you just want to connect two PCs directly without the hub... >> diagram below show you the distance: >> >> for 100baseTX (100 meters): >> >> PC <---------- 100 meters max ----------> PC >> >> you need crossover cable for that... >> >> for passive hub: >> >> PC <------- distance A -------> passive hub <------- distance B -------> PC >> <------- >> distance C --------> PC >> >> distance A + B is less than or equal to 100 meters >> distance A + C is less than or equal to 100 meters >> distance B + C is less than or equal to 100 meters >> >> for active hub... this is called now a switch... an active hub or >> switch has a repeater in it (unlike with passive hub which dont >> have)... repeater belongs to layer 1 or physical layer... >> >> function of a repeater is to extend network length... repeater receive >> and decode data from a worst case noise, timing and signal amplitude >> conditions.. it retransmits the data with the correct timing and >> amplitude as well as transmitting a jam signal throughout the network >> if a collision occurs... >> >> there are two classes of repeater/switch... class 1 and class 2.. >> >> class 1 switch can connect two different signaling (eg. 100baseTX and >> 100baseSX)... >> >> the diagram below show the distance depends on the 802.3 specification >> that you use: >> >> PC A <------- distance A ------> class1 switch <------- distance B -------> >> PC B >> >> if PC A and B used 100baseTX (100 meters): >> >> distance A + B is less than or equal to 200 meters but distance A >> and B must not more than 100 meters >> >> if PC A used 100baseTX (100 meters) and PC B used 1000baseSX (300 meters): >> >> distance A is less than or equal to 100 meters >> distance B is less than or equal to 300 meters >> distance A + B is less than or equal to 400 meters but distance A >> must not more than 100 meters and distance B must not more than 300 >> meters >> >> class 2 switch cannot connect two different signaling but can connect >> to another class 2 switch for additional ports... >> >> the diagram below show the cable length if you are using 100baseTX (100 >> meters): >> >> PC <-- distance A --> class 2 switch <-- distance C --> class 2 switch >> <-- distance B --> PC >> >> distance A and B must not more than 100 meters >> distance C must not more than 5 meters >> >> class 1 switch cannot connect to another class 1 switch... only one >> class 1 switch and two class 2 switches in a given collision >> domain.... >> >> take note.. in a given collision domain.. the above diagrams... its >> maximum cable length and number of switches that you can connect are >> all true if and only if your network topology have collisions... >> normally you have collisions in your network if it is configured as >> *half* duplex... >> >> you are limited by the distance of the diagrams above because of >> *round trip collision delay* that must conform with the 802.3 >> specification... >> >> but good news.. everything changed when full duplex came... ethernet >> is using carrier sense multiple access / collision detection or >> CSMA/CD access method... CSMA/CD is not CSMA/CD anymore because there >> is no more to sense the carrier before transmitting to avoid collision >> and no collision anymore if it is under full duplex mode :-> >> >> with that.. under full duplex mode.. there is no more to worry about >> round trip collision delay... so therefore... you can connect two or >> more switches to extend your network as long as the maximum distance >> cable used is within its distance specification and make sure that the >> ports are configured in full duplex mode.. >> >> fooler. >> _________________________________________________ >> Philippine Linux Users' Group (PLUG) Mailing List >> http://lists.linux.org.ph/mailman/listinfo/plug >> Searchable Archives: http://archives.free.net.ph >> > _________________________________________________ > Philippine Linux Users' Group (PLUG) Mailing List > http://lists.linux.org.ph/mailman/listinfo/plug > Searchable Archives: http://archives.free.net.ph > -- Ian Dexter R. 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