GNS3 how many routers

6stitches

Quick question: How many routers do I need to simulate for labs, currently I can simulate 8 routers with 128mb on each before I am out of memory. Is that enough for IE labs? Or will I need to upgrade.

reaper81

You need 13 routers for the full topology. 6 routers, 4 switches and 3 backbone devices. They are all running 3725 though. Read up on idle-PC, idlemax and sparsemem etc. How much RAM do you have? You can find a lot about this on my blog.

6stitches

reaper81 wrote: »

You need 13 routers for the full topology. 6 routers, 4 switches and 3 backbone devices. They are all running 3725 though. Read up on idle-PC, idlemax and sparsemem etc. How much RAM do you have? You can find a lot about this on my blog.

thanks reaper, I have about 3 gig (winxp 32 bit limits me, actual is 4gig). I did the idle-pc, I haven't looked at idle max, or sparsemem though, but will do. (and look for your blog)

6stitches

just an update, I can now run 13x7200 routers at about 2.44 Gig of memory. It takes about 25 secs to completely boot up 1 router, so that's what I used for delay.

I will try with 3725 next.

6 router, 3 backbone. so it's 9 routers, and the 4 switches will be external connected, correct?

reaper81

Good news.

If you want to run all the switching labs then yes you need 3x 3550/3560 externally connected. I simulate some of the switching with 3725 +NM-ESW but it is very limited.

6stitches

I am finding out that "*" value in front of idle-pc are not created equal. Took a little while to find the correct one for the 3725. Some of the values, you need to hit enter at the console to clear the CPU, I finally found the ones that didn't need that.

Currently running 12 x 3725 at idle at 2.95 GB memory, ios c3725-adventerprisek9-mz.124-16.bin

reaper81 wrote: »

Good news.

If you want to run all the switching labs then yes you need 3x 3550/3560 externally connected. I simulate some of the switching with 3725 +NM-ESW but it is very limited.

How many quad nics do you recommend to connect to external? I see some say 2 and others say 3.

CCIEWANNABE

yeah, if possible upgrade to 4 gig of ram. 1 gig of RAM these days is pretty cheap, probably less than $50 and it is worth it.

I run a 3725 12.4 image and can power up all the routers in INE's topology with 4 gig. granted most of the routers I run 128 mb.

The trick is to save your project, lab and routers often. And as you progress through the tasks, if you run into a task that requires more than 128 mb on a router, just power it down, and knock up the RAM to 192, boot it back up and you're good to go.

I can't tell you how many times I did this during my studies and I was always able to finish the labs by doing this. And all I had was 4 gig DDR3 ram, which is not impressive by todays standards.

There are only a few tasks that require the RAM to be knocked up from 128 to 192 RAM, usually they are the System Management, IP Services and real odd tasks.

Hope this helps and good luck!

gorebrush

You can put all the RAM in you want, but if you are limited to a 32-bit OS, you won't see any more of it...

64bit OS would be the same cost as some more memory and he could then use the "4th" Gb of mem

keenon

couple of quick things to note.

if your running this on a win32 system if you run 2003 server enterprise ed. you can use more than 4gb of ram and the system will note it.

always use ghostios, if your using routers that require more than 128mb of ram try to split the gns/dynamips processes accordingly. meaning for basic lab setup 6 routers -128mb each with 4 switches and 2 backbone devices run 2 processes. in dynamips that would be 7200 & 7201. if using 160+mb ram use 3 and split the routers as evenly as possible across each process 7200, 7201 & 7202.

concerning quad nics ebay has alot of cheap choices but be mindful picking an older quad nic it may not support dot1q. so a little research is required.

alan2308

gorebrush wrote: »

You can put all the RAM in you want, but if you are limited to a 32-bit OS, you won't see any more of it...

64bit OS would be the same cost as some more memory and he could then use the "4th" Gb of mem

This is only true with pretty much just desktop editions of Windows. Most of everything else supports PAE which allows for up to 64GB of RAM on a 32-bit OS. It's been there since the Pentium Pro.

instant000

6stitches wrote: »

I am finding out that "*" value in front of idle-pc are not created equal. Took a little while to find the correct one for the 3725. Some of the values, you need to hit enter at the console to clear the CPU, I finally found the ones that didn't need that.

^^^ Yes, that can be quite annoying, scrambling around having to hit enter in all your consoles for the CPU to be right ... what a bother