[c-nsp] VoIP QoS Service Policy Template

[Michael Markstaller]

> -----Original Message-----
> Andre Beck
> Sent: Wednesday, December 29, 2004 11:24 PM
> 
> On Fri, Dec 17, 2004 at 10:18:42AM -0800, Andrew Melton wrote:
> > Does anyone have a good policy-map for marking and queueing traffic
> > already marked with a DSCP?
> 
> Not yet, I'm still researching that new world for myself ;)

Maybe it helps, I've been using the LLQ below for a Videconferencing 
environment for quite a while now and verified this method really 
works on 2621 with 12.3
LLQ as a child-policy was they way I found to be best for minimizing 
packet loss in critical traffic. 

> > I'm not sure whether the best way to do this is with a policy-map
> > using a 'priority bandwidth' statement for that class which 
> matches on
> > the DSCP.  I'd have to have separate statements and policy-maps for
> > each interface of differing speeds using this method.

I ended up in defining bandwitdhs per interface, there are some things 
which prevented using bandwidth %

> > Any other suggestions on how to apply a queueing policy to this EF
> > traffic?  I know that there are a million ways to do it, 
> I'm trying to
> > find what has worked well for people and what hasn't.

below is what worked for me on 2621 boxes with IPSec, some notes:
- the average shaping for all traffic was done to minimize packet loss,
in this case mainly a "2621 aren't doing more than 1 MBit" thing.
they tend dropping things silently on higher load, thats why I decided
to
limit it to something reasonable at all - heavily depends on what you
try
to achieve, my objective was to ensure 100% VC-traffic
- priority (LLQ) drops exceeding traffic as far as I remember, so define
enough
- I marked the packets based on IP's in ACL

class-map match-any VC-Hosts
  match access-group 2601
class-map match-any VideoConf
  match ip precedence 4  5  6 

policy-map LLQ-VC
 description Child-policy for LLQ
  class VideoConf
   priority 960 96000

policy-map Mark-VideoConf
 description Input policy to mark packets from VC-hosts
  class VC-Hosts
   set ip precedence 5

policy-map Shape-WAN-out
 description Parent-policy to average WAN/VPN-traffic
  class class-default
   shape average 1024000
   service-policy LLQ-VC

crypto map XY xx ipsec-isakmp 
...
 qos pre-classify

interface Serial0/0.1 point-to-point
 service-policy output Shape-WAN-out

interface FastEthernet0/0
 service-policy input Mark-VideoConf