d_l
Barsoom
Premium,MVM
join:2002-12-08
Reno, NV
1 edit | reply to graffixjones
Re: [General] BEFSX41 / Siemens 4100 DSL Modem problem and solut
What I've done is basically set up my SX41 and 4100 just like you have. The SX41 makes the PPPoE connection and the modem's PPP is set to be "PPP on the computer".
Then my EZXS55W is inserted between the SX41 and 4100. The PPPoE encapsulated packets pass right through the switch.
A second router (I originally used an old SR41, but now I use a WRT54GS) is in "parallel" (not really the best way to describe the topology set up, but it is close) to the SX41. This second router is set to a static IP on the same LAN subnet and the DHCP is disabled on it. A patch cable connects one LAN port on the SX41 to a LAN port on the WRT. If you have ever spent any time on this forum, you will recognize this as the classic way to add wireless capability to your wired router with a wireless router. It also results in the net addition of two more switch ports to your network.
The classic "add a WAP method" says don't use your WAN port on the wireless router, but for my set up, you will connect the WAN port to the switch and set the second router's WAN to internet connection type of DHCP. The 4100 will always issue the 192.168.1.64 IP to the WAN port of the second router.
Now here is the tricky part and I don't know if you can even do this with a Mac. The computer, SX41, and second router can't seem to consistently get its static routing through through the switch side of the SX41 and on to the second router and then out to the modem unless you set up a static route in the computer.
In Windows, this is done with the route add command. I use these two routes with the persistent switch set:
route -p add 192.168.0.0 mask 255.255.255.0 "2nd Router IP" metric 5
route -p add 192.168.1.0 mask 255.255.255.0 "2nd Router IP" metric 5
These routes will get your packets to the modem and to the WAN side of the second router (which really serves no pressing purpose). 
The disadvantages of this method:
•It costs more with the second router and switch.
•It uses more power.
•Once in a blue moon (every 2-3 months) the switch will twitch and the router will drop the PPPoE connection and reboot (this may just be random reboots of the SX41).
The advantages:
•You can check the modem's stats without relying on the modem's pass along of de-encapsulated packets which may cause problems for a VPN connection.
•You can actually reboot the modem from its GUI with out losing your PPP connection. The connection is broken while the modem reboots, but you resume your link and IP once the reboot is finished.
•You can continuously pull stats from the modem AND continuously ping a site on the internet for diagnostic purposes. This can't be reliably done when the modem is making the PPPoE connection. Generating the stats output is a big load for its CPU and it sometimes get scrambled and unable to PPPoE encapsulate outgoing packets. If the PPPoE encapsulation is off loaded to the SX41, then there isn't a problem doing both.
Edit: It goes without saying that all these network devices and modem positively need some sort of UPS back up power. A power drop or fluctuation besides frying your equipment can wreak havoc on the stability of this set up. |
