* Challenges of moving to PPPoE
Last time around, we discussed Steve’s ADSL service provider’s move from authentication via Ethernet address of the attached device to Point-to-Point Protocols over Ethernet (PPPoE). The basic move went fine, and it provided some advantages for both Steve and the service provider. But it also presented a challenge or two.
The first challenge had to do with the fact that, as we’ve discussed often in the past, Steve is one of those people who is so hooked on broadband access that he actually uses both DSL and cable modem. And there’s a fundamental difference in the way these two technologies authenticate a user as a valid network user. For cable services – at least in Steve’s case – the cable modem itself is used to provide authentication, and then is provides DHCP service to whatever device is attached – router or PC.
The DSL modem, on the other hand, did none of the authentication, and it depended on getting an Ethernet address from the attached device. So long as the router was configured with the proper Ethernet address for the DSL service, then moving back and forth between the services was as simple as moving the Ethernet cable from the router from the cable modem to the DSL modem.
This was especially convenient since neither service was 100% reliable. However, the odds of both services going flaky simultaneously are really slim. In fact, getting into the arithmetic, if you have two services that are only 95% availability (and both services are much better than this), the availability of at least one of the services for a given time is 99.75%.
Now, however, since the DSL modem and the cable modem use different authentication schemes, the router has to be reprogrammed and reset – not exactly rocket science but still a pain in the patoot – every time the service needs to move between the broadband services. And, as you may remember, we’re still on the quest for the cost-effective router with active dual WAN links that we think is up to snuff.
So, as a SOHO “power user,” this is not a showstopper for most users. But it does indeed complicate the support environment a bit as more and more enterprises are faced with supporting a variety of teleworkers in the virtual office.
Next newsletter we’ll wrap up this particular discussion with a somewhat surprising revelation of a situation where 8-bytes of overhead actually makes a difference.
