----- Original Message ----- From: Sent: Friday, June 29, 2001 10:06 AM Subject: hi http://www.geocities.com/nagendra_pratap_singh > Todd Lammle book-pg.20. This is what he has written. > "Switches cannot translate between different media types. In other words, > each device connected to the switch must use an Ethernet frame type. If you > wanted to connect to a Token Ring switch or LAN, you would need a router > to provide the translation services." > 1st of all, what does media types mean? Does it mean ethernet > 802.3,2,frame-relay,atm,tokenring,etc? Is LAN also a media type? > Secondly, is the above statement saying that if you want to connect > supposing ethernet 802.3 to token ring you cannot do it with a switch. > Well a Switch or a SWITCHED HUD is just a hub with address detection facilty and the ability to sent the broadcast to only selected nodes depending upon the types of packet Also a hub is only a muliport repeater. That is a special amplifier that cleans the signal and boosts/corrects it to the specified 0 and 1 levels. Its is almost the same thing as a BUS network but with the facility of easy connectors, immunity to any link going down and lights to show some status light esp power and canle conection. LAN is a generic term and is not related to any types such as 802.3 etc . people had lans before it too. Now token ring : token ring is a prop tech. the maximum limit is 16 MBPS as compared to 100 MBps of ethernet. here is a meesage if started from n1 to n100 then it would need 99 hops and will waste time. by contrast the switch just does the exact thing and cuts the fat. in a token network you can think it like a queue outside a bathroom. every one will get his or her chance but it may take forever. In switches its like an attached bathroom. BTW token ring has a priority scheme too Media type is a media type :) . Well the examples are utp/stp, coax, IR/laser, acoustic and optic fibre ( its has some propertie of laser /ir type) . what may differ is a media acess contol method ( token ring, ethernet etc). a 0 or 1 be repesented by a ant thing like hi/lo frequency, hi/lo voltage, 0/5 volts. since the hubs/switches dont know much about packets except for origin and destination ( hubs dont know anything, they are like a photocopy machine(anything black is to be copied), switch is like a new student of the language who has learnt the alphabet and can distinguish between stains and letters.) so they cant translate the types a router can strip a lot of information from the packet and can add a lot to it too thus bypassing and freeing itself from the MAC layer. the language on top is the same and a smile is the same in all languages. I need a pic to show it http://www.geocities.com/nagendra_pratap_singh > -------- > *How many hosts can a port on a switch support? What topology can be > used on each port? I guess it connot be ring. According to me it can be > bus. > Can it also be star and all the hosts are connected to the hub and the > hub is connected to the switch? But this wont serve any purpose since > the hub wont even make a collision domain. > Normally what topology is used? 1 on each i think. hub does make a collison domain the hub has the same coll/brdcast domain. but a switch can brdcast as a hub but stops collision by giving dedicated access to the network > ------- > *SwitchA has 25 ports. Now supposing hostR on port1 has to communicate > with hostS on port2 but hostR doesnt know hostS's ip address and neither > is hostS's ip address listed in the switch's filter table, then does the > switch accept the packet and does a broadcast to all the 25 ports? if its not listed then they will broadcast the packet on all active ports except for the origin. someone will reply and will give his mac address in the packet. this will be added to a table. I must mention that TCP/IP is NOT THE ONLY protocol that works with hubs/switches. they dont use IP addys or network layer addy. they use a simpler addy (mac addy). switches/hubs are made for ethernet http://www.geocities.com/nagendra_pratap_singh > ----------- > Now this quest.might sound silly but i just was going deep into the > topic. Now supposing i dont want this broadcast to happen, what can i > do? Can i just issue a command on the switch by which it would learn all > > the hosts and add them to the filter table? Or is there any other device > i can use? some switches an be programmed. some can be upgraded to programmable status. your kilometerage ( mileage) may vary. a broadcast should get a reply from any active host and thus create a mac table. > > -------------- > Usually when networks are connected to routers,either the hub/switch is > connected to the router and the nodes are connected to the hub/switch. > Is it possible to connect a node directly to the router? > What interface does one use in this case? > And is this kind of arrangement ever used? > yes it is. cost ils like this router > switch >hub. the idea is that a network should keep most traffic local and backbone should be used sparingly. for real life it means that everyone should join a local office and send the children to a local school. thi sway they can avoid the problems realted with crosiinf the town 2 times a day and the hiways remain free. I need a pic to show it ethernet interface is the best i feel. > -------------- > Supposing you have two networks of 25 hosts and each of these 25 hosts > are connected to switchA and switchB. Both the switches are connected to > the router. Now when a host on switchA wants to communicate with a host > on switchB the packet goes through the router and the router sends the > packet to switchB. Right? > yes . three middlemen /middlewomen/ middlepersons are used http://www.geocities.com/nagendra_pratap_singh > hey thx a lot.. > bye Message Posted at: http://www.groupstudy.com/form/read.php?f=7&i=10396&t=10396 -------------------------------------------------- FAQ, list archives, and subscription info: http://www.groupstudy.com/list/cisco.html Report misconduct and Nondisclosure violations to [EMAIL PROTECTED]
