[c-nsp] QoS/NBAR 7200 for L2TP ADSL

[Tim Franklin]

> OK, currently because usage on ADSL lines is a problem in the UK (and 
> I'm guessing in other places too), caps are put on ADSL lines to stop 
> people abusing them. Unfortunately, caps don't always do 
> their jobs, and 
> people just abuse them anyway.

Alternatively, broken business models on ADSL lines are a problem in the UK.

Basing a business model on the fact that people won't use a service, but
covering the accompanying advertising in words like "unlimited" was always
going to end in disaster.

Not pointing the finger at you or your company in particular, but missing
the economic fundamental that the price of a product needs to be higher than
the costs of providing that product, then screaming for all kinds of
technical band-aids to try and "fix" people using the service they've been
sold is one of my pet bug-bears, and appears to be pretty much endemic to UK
consumer broadband.  (The other being products sold as "Internet" access
that aren't clear and up-front about which filtered / proxied / NAT'd /
AUP'd subset of the Internet they're prepared to give you access to.)


Soapbox aside, if you have the spare ports available, you could:

- put in a loop between a GE-WAN port on an OSM or similar into a
GigabitEthernet (LAN) port
- trunk both ports
- put the LAN port facing the 7200 as an access port in a free VLAN
- shape outbound on the corresponding sub-interface on the GE-WAN

It's a nasty hack, and it's expensive in terms of ports, but if you've got
several access devices hung off FE LAN ports that need this kind of shaping,
it's one way to get there.

Regards,
Tim.

-- 
____________   Tim Franklin                 e: tim.franklin at colt.net 
\C/\O/\L/\T/   Network Development &        w: www.colt.net 
 V  V  V  V    Product Engineering          t: +44 20 7863 5714 
Data | Voice | Managed Services             f: +44 20 7863 5876