Memory, routers and servers - 857=Poof!! I think?

Unanswered Question
Dec 3rd, 2008
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Hi,


erm how to put this one? (CCNA guy here :)! )


When dealing with mulitple servers requiring many ports on the NAT to be forwarded (outside -> inside) how does one calculate the amount of memory required for the router to be chosen.


This suddenly dawned on me today as I experianced some NAT errors with 857W which after an IOS update are now gone. However all of a sudden my browser wouldn't connect to a site so thinking it was the machine (an old Apple PowerBook G3 400MHz running Fedora 9) I decided to wait a little for the cpu to come back down to earth from 100%.


However for a few hours it made no difference. So I tried my PC much faster machine (PIV 3.2GHz) and same thing.


So I tested connectivity between my network with the outside world and ping from both router and terminal came up with 20% packet loss. DNS was working fine and as far as I could tell everything was too.


Then I realized that because I'm running 4 servers and 5 other clients on my network which one of the servers runs the Darwin Streaming Server (RTSP streaming services) and I have many udp ports opened up because of this that my router may have run out of memory.


Now I don't know if there's any command that can show the memory usage in terms of a percentage? But when I typed in: show memory fast


there was a lot of information in there so I'm guessing that I ran out somwhere.


I remember reading up articles on consumer routers that claimed that teh 8MB or whatever you get isn't enough to run services with and is a reason why they crash so much (main reason I switched from my D-Link to the Cisco).


However in the 'real world' how would you way up how much memory you actually needed?


I guess the 800 series wasn't designed to be running servers but something like the 1800's with double the memory-upgradeable or the 2800's maybe able to handle the load especially if you wanted to run VPN tunnels too from the router not from a server say.


Uh I don't know if I'm just having a mid-CCNA crises or the fact that I can't find a job but so many burning questions......

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kayasaman Wed, 12/03/2008 - 19:04
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Wow, I've managed to find teh command: show memory statistics whoohoo :-)


....only that it's quite high?


Head Total(b) Used(b) Free(b) Lowest(b) Largest(b)

Processor 81FAA55C 27613860 18898364 8715496 8317092 8317088

I/O 3A00000 6291456 4055080 2236376 2236376 2236348


This is after trimming the config down and getting rid of my failed VPDN config attempt and taking off some redundant ports from the NAT forwarding process. If routers behave anything like PC's memory wise this will continue to go up. Will have to check the mem stats later on.


In reality though no one would use an 800 for setting up with servers I guess unless it was an internal file server or perhaps a small FTP. So what kind of routers might be used for that?


Is there a rule like say: 64MB RAM = 1 server running 2 processes (say ftp and http)??


Am I still thinking like 'student' and actually one would get an expensive 1Gbps 2800 series or greater with 'leased lines'?

- or simply could you use an 1800 or 2801 say?

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