ccna doubts plz clarify it i am beginner

purni

can router have collision and broadcast domains????
in terms of cable computer and router are unlike or like devices and why? how?
plz have a test for me explain in detailed

agplt

purni wrote: »

can router have collision and broadcast domains????
in terms of cable computer and router are unlike or like devices and why? how?
plz have a test for me explain in detailed

It's good thing that you asked, because i am studying either for CCNA(ICND1) at first glance i thought it's easy but now i am trying to answer it in my head and beeeeeb i can't I only can think logically, that router have one collision domain per port the same as switch, about broadcast domain hm.. Computer can be a router but i don't think that they are like devices. Yeah i know my response is good as blank paper... I'm looking forward for answer

hypnotoad

In short, Yes and Yes. Router's ports have switch-like logic so they don't have collision issues like hubs. Most routers with switching built-in are advertised as switches as well -- both Cisco and small office/home office ones like linksys. Cisco routers can have switched ports built in, or you can add on a module with switch ports. It's similar with other vendors like Juniper.

The hub is the key element in a collision domain. The hub is basically a dumb repeater. It gets the signal, forwards it out all ports because it doesn't really know where the signal (the ethernet frame) is supposed to go. The switch is smarter than that, keeps track of the MAC addresses of various connected things, and sends the frame to the right destination. Modern routers act like switches (and modern switches act like routers, but thats another story). Their ports are smart enough to know where things go at Layer 2.

Routers also stop broadcasts by default. If a broadcast comes in on port FastEthernet 0/0, for example, it won't get sent out FastEthernet 0/1. Unless you tell it to. And at home...if your computer sends out a DHCP request (a common broadcast packet) to your linksys router, the router won't send it on to the ISP. Broadcasts are local to the subnet -- it's one of the main reasons for breaking networks down into subnets.

gosh1976

agplt wrote: »

It's good thing that you asked, because i am studying either for CCNA(ICND1) at first glance i thought it's easy but now i am trying to answer it in my head and beeeeeb i can't I only can think logically, that router have one collision domain per port the same as switch, about broadcast domain hm.. Computer can be a router but i don't think that they are like devices. Yeah i know my response is good as blank paper... I'm looking forward for answer

PC and Router are like devices and for the purposes of the ICND1 they would use a crossover cable.

agplt

gosh1976 wrote: »

PC and Router are like devices and for the purposes of the ICND1 they would use a crossover cable.

It supposed to be this way, is it true that nowadays you can connect like devices like pc and router with straight-thru cable because router automatically recognizes or do something, for real i don't get it why you supposed to use different cabling, i know that the max distance of cable varies on wiring but here is same 100 meters.

networker050184

agplt wrote: »

It supposed to be this way, is it true that nowadays you can connect like devices like pc and router with straight-thru cable because router automatically recognizes or do something, for real i don't get it why you supposed to use different cabling, i know that the max distance of cable varies on wiring but here is same 100 meters.

You have to use a crossover (unless the device is autosensing) because the transmit and receive pins must line up. If you are transmitting on a pair and you have it connected to the other ends transmit communication isn't going to work too well. You need the transmit on one end connected to the receive on the other.

alan2308

agplt wrote: »

It supposed to be this way, is it true that nowadays you can connect like devices like pc and router with straight-thru cable because router automatically recognizes or do something, for real i don't get it why you supposed to use different cabling, i know that the max distance of cable varies on wiring but here is same 100 meters.

You should still know which cables to use in every situation. For one, you can't just assume that every device you'll ever encounter will be able to auto-detect and that the auto-detect will always work. Secondly, the exam objectives will expect you to know which cable to use and why. And third, its a part of understanding how Ethernet works.