my second stupid question

how many telent sessions can take place simulaneously on a router running a standard edition of the IOS?why?

Well IOS provides 5 virtual terminals if I remember correctly..
thats why you use the command

vty 0 4
to configure the telnet interfaces.

yes,but I think not so easy .I am so puzzled .after all ,it's one question in cisco exam!may be you are right!

A Note here, the new IOS's now provide upto 16 telnet sessions as opposed to 5 in the older ones !!

This means you now have from VTY 0 to 15 !

If I remember correctly .. the above changes apply from versions 12.0 or 12.2 and upwards.

Now thats something I didn't know.. so when you configure you have to go
vty 0 15 ?

Hehe so if people didn't change their configuration from the old 11.x configs to the new IOS version.... they would not have configured all the vtys.... right ?

Btw gladiator.. its quite a typical Cisco question.. they can ask some really lame questions and you get tricked into thinking 'it can't be this easy'..

I have not had the chance to work a lot with 12.1 and above yet. I do know that on a router with 12.0 the vty is still 0 4. On switches it is 0 15. I would not consider a layer 3 switch as a router.

Also, I did a quick search on www.cisco.com and found evidence that at least up to 12.1 a router is still VTY 0 4. Switchs are VTY 0 15.