Configuring FTTC (Infinity) with a Cisco 887 VA router

Curiosity eventually burned a big hole in my pocket and the new Cisco 887VA arrived today. Previously I had set up FTTC (Infinity) on a Cisco 861, which is ‘ethernet only’ and utilised the BT supplied VDSL modem. This new 887VA has a bult in VDSL modem and I suspected that we would get better results from it. The 887VA has a kind of ‘hybrid’ RJ11 port for both VDSL and ADSL. We got the one with the ‘Security’ feature set which added a few quid, but this may be an internet facing router at some point.

Before we start, there are a few things to note about the setup…

  • You can use ADSL or VDSL – not both.
  • Whichever one you are not using should be shut down.
  • ADSL uses the ATM interface as always.
  • VDSL uses the Ethernet 0 interface
  • If you are using BT’s FTTC (Infinity) the VDSL uses tagged frames in vlan 101

The router has plenty of grunt for a soho router, so I’m hoping the usual CPU pegging will not be an issue:

Cisco 887VA (MPC8300) processor (revision 1.0) with 236544K/25600K bytes of memory.
Processor board ID FCZ1614C4X7

1 DSL controller
1 Ethernet interface
4 FastEthernet interfaces
1 ATM interface
1 Virtual Private Network (VPN) Module
256K bytes of non-volatile configuration memory.
125440K bytes of ATA CompactFlash (Read/Write)

You can see the strange ‘Ethernet’ interface there as well as the ATM interface. Now how to configure it…

Set up the VDSL interface

interface Ethernet0
 no ip address
!
interface Ethernet0.101
 encapsulation dot1Q 101
 pppoe-client dial-pool-number 1

Shut down the ATM interface

interface ATM0
 shutdown

Create the Dialer interface

interface Dialer0
 ip address negotiated
 ip virtual-reassembly in
 encapsulation ppp
 dialer pool 1
 ppp authentication chap callin
 ppp chap hostname umbo-jumbo@gconnect
 ppp chap password super_secret_password

We also set up some NAT and other features, but thats all standard stuff. Speed tests showed a very healthy 37MBits/second download and 4.5 MBits/second upload which was a significant uplift from the other arrangements using a Draytek 2820 for FTTC or the other Cisco 861, both of which used the BT supplied VDSL modem and both of which showed around 25MBits/second. The good thing is we can now see data about the VDSL connection that we cannot see with the modem. The command we used to use for displaying dsl data was: show dsl interface atm0 , and that has bee depreciated, the new version is below:

sh controller VDSL 0
<snip>
 		  DS Channel1	  DS Channel0	US Channel1	  US Channel0
Speed (kbps):	          0	       39998	         0	       10000
Previous Speed:	          0	           0	         0	           0
Reed-Solomon EC:          0	           0	         0	           0
CRC Errors:	          0	           0	         0	           0
Header Errors:	          0	           0	         0	           0
Interleave (ms):       0.00	        0.00	      0.00	        0.00
Actual INP:	       0.00	        0.00	      0.00	        0.00

and yet interestingly, earlier in the output the following appears:

Modem Status:		 TC Sync (Showtime!)
DSL Config Mode:	 AUTO
Trained Mode:		 G.993.2 (VDSL2) Profile 17a
TC Mode:		 PTM
Selftest Result:	 0x00
DELT configuration:	 disabled
DELT state:		 not running
Trellis:		 ON			  ON
Line Attenuation:	  0.0 dB		  0.0 dB
Signal Attenuation:	  0.0 dB		  0.0 dB
Noise Margin:		 30.6 dB		 31.0 dB
Attainable Rate:	125892 kbits/s		 36532 kbits/s
Actual Power:		 13.6 dBm		 - 7.6 dBm

Does that really say 125 MBits/second for the attainable rate on the download?

Well thats about it for this post, I hope its been helpful. Gconnect sell FTTC Broadband accounts for business and home, and as the sponsors of this blog, please go ahead and take a look!

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