[c-nsp] QoS on LNS virtual-template

[Dean Smith]

I do think you'll need the parent/child setup. The problems start with
knowing what to set the parent policer to. If all you're sessions are fixed
B/W then you can hard code it. If you have a mix then you may have more of a
challenge.

Some providers pass through the downstream B/W from the DSLAM/LAC to the LNS
- many don't (check if your VAI have the right bandwidth). And setting your
QoS to the negotiated DSL rate may not of course mean that all the traffic
gets through the provider network from your LNS to the DSLAM, so you might
prioritise all you like on the LNS...and get wholly arbitary drops from your
provider. If they offer QoS then you'll need to mirror your QoS marking to
the L2TP encapsulated packet with "ip tos reflect" in the VPDN group.

The latest 12.2SB have been better for us for QoS on L2TP VAI, but in
general it seems flaky and small code changes can have a big impact on a)
whether it works at all and b) how well it works.

To be confident....you'll need a lot of testing.

Dean


-----Original Message-----
From: cisco-nsp-bounces at puck.nether.net
[mailto:cisco-nsp-bounces at puck.nether.net] On Behalf Of Clue Store
Sent: 30 November 2009 21:29
To: Cisco-nsp
Subject: [c-nsp] QoS on LNS virtual-template

Hi All,

I went through the archives and couldn't find specifically what I was
looking for and of course, most of the Cisco links are broken now, but I
noticed that QoS is applied to my virtual-template interface in my config,
but when I do a "show policy-map interface virtual-access xx", I get nothing
as if the policy wasn't inhereted. When I look at my policy-maps, I also
noticed that I do not have parent/child policies configured (which I am to
understand how you have to configure QoS like this on this type of
interface). Here's an example of what I have on our LNS boxes....

First question, do I need a child/parent policy to attach the service-policy
to the virtual-template?

Second question, do I need to have the "qos pre-classify" command on the
virtual-template??

Third question, does anyone see anything wrong with the way this is
configured??



class-map match-all VOIP
  match access-group name VoicePorts
  match ip rtp 16384 16383
  match ip dscp ef


policy-map DSL
  class VOIP
   priority percent 75
  class class-default
   fair-queue
   random-detect


interface Virtual-Template2
 mtu 1460
 ip unnumbered Loopback2
 service-policy output DSL
 ip route-cache flow
 ip tcp adjust-mss 1420
 ip policy route-map clear-df
 qos pre-classify
 peer default ip address dhcp
 ppp authentication pap
 ppp ipcp mask 255.255.255.0
 ppp ipcp address accept

ip access-list extended VoicePorts
 permit udp host x.x.x.x range 22026 62025 any
 permit udp host x.x.x.x range 22026 62025 any


TIA,
Clue
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