Chris, Thanks for the detailed explanation. The way you explained it does seem to match up with the graphs I am seeing.
Some questions/observations: 1) IF3 and IF4 just seem to be splitting up the data that I can also see on IF1. Is that correct or am I missing some subtelty as to whay it is split that way? 2) IF1 is the same data, just in reverse, of what I am seeing on the server's eth0. Again, is that correct or am I missing something? 3) If the above are correct, if I want to graph my internet traffic, all I really need to grapg is my server's eth0. I don't see any value-added to graphing the interfaces on the cablemode. Is this correct too? Thanks! ...Jake >>>>> "CAC" == Christopher A Congdon <[EMAIL PROTECTED]> writes: CAC> I don't know the ins and outs of cable modems in general, but it CAC> seems to me that what you *should* see if this thing adheres to CAC> certain standards... CAC> Interface 1) You should see inbound and outbound traffic. Inbound CAC> should represent the traffic you are sending from your network to the CAC> 'net. Outbound should represent traffic your modem is receiving from CAC> the 'net and being transmitted to your network. CAC> Interface 2) This is probably some sort of 'internal' interface. Many CAC> devices have if's like this and can be ignored. CAC> Interface 3/4) You may want to look into combining these two CAC> interfaces as the same graph. I'm not sure why they are separately CAC> listed interfaces, but IF3 should be your Internet to LAN traffic and CAC> IF4 should be your LAN to Internet traffic. CAC> Interface 5) This would be the traffic you would see if you had a USB CAC> cable hooked up to your cable modem. If you're not using USB, you can CAC> comment out this IF. CAC> If your server is doing most of the Internet traffic on your network, CAC> it is no surprise that the IF3 matches your server's inbound CAC> traffic. Since your server is pulling packets from the 'Net, they CAC> have to follow through the inbound interface on your Cable Modem, CAC> which is IF3. You should see a matching graph of Outbound Traffic CAC> color on the Cable's IF1. This also means that your server's ETH0 CAC> outbound should be a close match for the cable's IF4. CAC> Judging by the Configmaker interfaces, it is no surprise that IF4 CAC> only shows outbound traffic. IF1 however should show inbound and CAC> outbound...after all, it should be a standard Ethernet interface. CAC> Again, your best bet is to have MRTG make two graphs for you, one CAC> showing inbound and outbound for the cable's IF1, and a combo graph CAC> showing IF3 as inbound and IF4 as outbound traffic. CAC> Chris >> -----Original Message----- >> From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] CAC> On >> Behalf Of Jake Colman >> Sent: Tuesday, June 07, 2005 09:00 >> To: [EMAIL PROTECTED] >> Subject: [mrtg] CableModem Interfaces >> >> >> I have a cablemodem connected to eth0; eth1 is used for the internal >> network. I used cfgmaker to create a config for eth0 and for the >> interfaces >> on the cablemodem (a docsis-compatible SB5100). >> >> I don't understand what the various cablemodem interfaces mean nor do CAC> I >> understand how I can use these interfaces to graph the bandwidth I am >> using >> when connected to the internet. >> >> cfgmaker found 4 interfaces on the SB5100: >> >> 1) ifType: ethernetCsmacd (6); ifName: eth0 >> 2) skipped >> 3) ifType: CATV Downstream Interface (128); ifname: <none> >> 4) ifType: CATV Upstream Interface (129); ifname: <none> >> 5) ifType: (160); ifName: usb0 >> >> The downstream interface (interface 3) seems to have exactly the same >> graph >> for incoming bytes as that shown for my server's eth0 interface. >> >> Interfaces 1 and 4 show only outbound bytes but I have no idea what CAC> this >> represents. Can anyone explain? >> >> Ultimately, what I'd like to graph is the amount of my available CAC> bandwidth >> that I am currently consuming in both directions. Any suggestions how CAC> to >> do >> this? >> >> TIA! >> >> ...Jake >> >> -- >> Jake Colman >> Sr. Applications Developer >> Principia Partners LLC >> Harborside Financial Center >> 1001 Plaza Two >> Jersey City, NJ 07311 >> (201) 209-2467 >> www.principiapartners.com >> >> -- >> Unsubscribe mailto:[EMAIL PROTECTED] >> Archive http://lists.ee.ethz.ch/mrtg >> FAQ http://faq.mrtg.org Homepage http://www.mrtg.org >> WebAdmin http://lists.ee.ethz.ch/lsg2.cgi >> -- Jake Colman Sr. Applications Developer Principia Partners LLC Harborside Financial Center 1001 Plaza Two Jersey City, NJ 07311 (201) 209-2467 www.principiapartners.com -- Unsubscribe mailto:[EMAIL PROTECTED] Archive http://lists.ee.ethz.ch/mrtg FAQ http://faq.mrtg.org Homepage http://www.mrtg.org WebAdmin http://lists.ee.ethz.ch/lsg2.cgi
