|
|
| SurfinUSA 2002-02-20, 2:46 pm |
| Guys, I cover several sites that have implimentations of cisco routers. I have noticed that on some of these sites, the modem is attached into the "aux" port and on others the modem is attached to the "console" port. Is this correct? Everything appears to be working fine as far as dial in, but how can this be attached to the console port like that? | |
| scoulter 2002-02-20, 4:32 pm |
| Hi,
Yeah thats fine, the norm is to hang a modem off the AUX port but unless you use the term mon commmand you wont see any debug output or status changes coming through your out of band connection.
Console port is normally used for onsite access, but i wouldn't be to concerned about this setup | |
| Yankee 2002-02-20, 7:43 pm |
| Actually there is a concern. If the site loses power and both the router and modem power on at the same time (with the modem attached to the console port) the modem will confuse the router and make it boot to ROMMON mode. This is a real pain at a remote site. Others can explain why this happens, but suffice it to say it is a better idea to keep your modem on your AUX port and not the console.
Yankee | |
| SurfinUSA 2002-02-20, 11:11 pm |
| Thanks Yankee. I remember this from CCNA, but when I saw this in real life, it was somewhat confusing and I thought I should ask the gurus here in the forum. Thanks. I know I have set mine up correctly. | |
|
| quote:
Originally posted by Yankee
Others can explain why this happens, but suffice it to say it is a better idea to keep your modem on your AUX port and not the console.
Yankee
As everyone knows when you reboot a switch when connected with hyperterminal you get an output on the screen.
I believe that the modem does a similar thing, outputs characters when it's rebooting, if the modem is connected via the console these characters from the modem are inputted into the router - It is theoretically possible that these characters could place you in rommon mode (as if you issued the command via hyperterminal).
There is an AT command to disable this happening, but probably better not to connect the modem to the console as already advised. | |
| SurfinUSA 2002-02-21, 8:09 am |
| If it is connected to the console port, should someone be able to dial in and do configuration on the router? | |
|
| I have to disagree with these posts, A modem connected to the console will allow you to actually simulate as if your logged into the console locally.
Meaning when your are troubleshooting issues you can reboot the router, stay connected and recieve console messages, which are often times critical to solving any kind of problem. Yes, you may encounter the above mentioned issue, but more than likely, you are disabling your eyes, for a problem that will never happen..
We by default install all of our modems to the console ports, and let me tell you its a lot of modems.
just my 2cents..... | |
| Yankee 2002-02-21, 7:37 pm |
| Well 007, lemme tell ya I have over 250 remote sites almost all with modems attached to the AUX port because while it is not often that our UPS doesn't support our equipment suite, it is not worth the risk of the router booting to rommon should the UPS not outlast the outage and they boot together. Go ahead and test it and maybe they'll think you know your stuff when you point out the flaw in their design. Picture a secure closet with limited access and the techs with the key are out sick and or in training...no one to reboot the router manually. You have a down site because ya didn't design it properly.
The strength of a network is based on good design, minimizing risk and adding redundancy when you can.
Yankee | |
| SurfinUSA 2002-02-21, 7:52 pm |
| I think I agree with Yankee. Besides, why would Cisco put an auxiliary port when they could just use the console port. Seems like there is a specific purpose for each one. | |
| The Reamer 2002-02-21, 8:10 pm |
| One way to avoid this kind of problem would be to use a device like the APC master switch. With this you can have a delay programmed into the plug providing power to the modem.
HTH,
Reamer | |
|
|
|
|
|
|