[c-nsp] Routing within a L2TP session using VPDNs

Alex Foster afoster at gammatelecom.com
Fri Feb 10 06:15:03 EST 2006

I am trying to set up a number of L2TP sessions to a 3620 using VPDNs. The
LAC is non cisco product - but works well and I have the tunnels established
and working.  What Im not sure about is how to route to the client network
on the back of the LAC.  Diagram:

Client Network------LAC--------LNS-------ISP

Its a basic config on the 3620 using the default VPDN group and a

At the moment the only way I can route to the client network (from the ISP
network) is to configure a static route on the LNS (to the client network)
via the tunnel address on the LAC (this address is assigned by the LAC).  I
need to scale this network beyond a few thousand users (3620 is only a test
box at the moment) so adding static routes to each client network isnt
ideal - Im also not keen on using routing protocols.  Any help would be


vpdn-group Access
! Default L2TP VPDN group
  protocol l2tp
  virtual-template 1
 no l2tp tunnel authentication
interface loopback 0
 ip address
interface FastEthernet1/0
 ip address
interface FastEthernet1/1
 ip address
interface Virtual-Template1
 ip unnumbered Loopback0
ip route

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