[c-nsp] ADSL Bridging over Ethernet

[Aaron Riemer]

Hi Guys,

 

This is not really a cisco specific question. I just need some clarification
on ADSL bridging.

 

I have a situation where an ISP will deliver a /29 address block over an
ADSL connection. I assume the ADSL connection will be PPPoA / PPPoE based.

 

The ADSL router is a simple consumer grade product and a firewall will sit
behind with a public IP address on an Ethernet interface within this /29
block.

 

My question is if I have this /29 block how can the ADSL router be addressed
LAN/WAN? I assume the only way to do this is to bridge the ADSL connection
to the Ethernet network?

 

If I bridge the connection does this mean the firewall will need to run the
PPPoE/PPPoA protocol? 

 

I am confused as to where the encapsulation / de-encapsulation occurs with
this type of design. The ADSL router or the firewall? Can I have the ADSL
router take care of all the necessary PPP functions such as authentication
etc with bridging?

 

Can someone please shed some light?

 

Thanks,

 

-Aaron.