If i power cycle VDSL modem - how is my PPPOE session/ip address mantained?

[thetransporter]

I was curious -

I have a router connected to a vdsl modem using PPPOE - i powered cycle the modem, and noticed the pppoe session still functioning. does it got dormant (like 1x use to do) for a little bit?

[eblend]

I don't know about PPOE sessions or anything specific to that tech, but as for your IP address, it's maintained on the DHCP server of your ISP based on the MAC address of your modem, with a set TTL (time to live). Once the TTL is reached, the IP address expires if it doesn't renew, so if your device is powered off for an extended period of time, your DHCP record will expire and be freed up. A DHCP renewal usually takes place at 50% of TTL, so if your TTL is 8 hours, at 4 hour mark it will start trying to renew, and at 8 hours it disappears. If your modem is turned off for 8 hours in this example, next time it is powered on, it will get a new IP address.

This is the same reason why people who don't buy a static IP usually maintain the same IP from their ISP for a while. I think some of them expire the leases regardless to force a new IP on you at next renewal, if only to make you shell out the cash for a static IP.

Sorry if this isn't what you were looking for.

[Zhariak]

Keep in mind that in most live connections (that you actually keep live), in most cases a change in your dynamic IP is rare...

It's been a while since I've used a dynamic, but back in the day, whenever DHCP renewal time came around, I'd be dished the same IP (unless of course you're offline for an extended amount of time).

[thetransporter]

interesting posts ^

iam using AOL PPPOE its dynamic IP address


somehow session is maintained or paused even if swap DSL modems , maybe pppoe has a different path...... i have no idea. oh well - this info is out there if any one needs to power cycle a modem