From: simon hart (simon.hart@btinternet.com)
Date: Fri Feb 18 2005 - 15:28:49 GMT-3
Hi Aji,
See if I can help out.
When the Doc CD refers to the edge of the network, I think they are
referring to the edge of the domain that you are in control off. So where
would you put CAR?
Suppose you have an uplink to an ISP, the physical link is 2Mb but you
service bandwidth provided by your ISP is 512k. In all probability your ISP
will limit the physical link at the ingress with CAR at 512k both inbound
and outbound (at least that is what we do at COLT). Therefore any traffic
you send above and beyond 512k will get dropped. From the Service Provider
point of view they have applied CAR on the network edge i.e. in and out of
their network.
Now you may wish to adopt a similar technique on your network edge to your
Service Provider, so that you are not sending packets into the 'ether'. You
would probably adopt either CAR of Traffic Shaping (GTS/CBWFQ) outbound, and
this is on your network edge.
Service-policy in our out is an interesting one. Take the example above, if
you where to traffic shape or rate-limit (CAR equivalent) to the ISP you
would create a Class Map and Policy map and apply as Service-policy out the
interface connecting to the ISP. You can traffic shape the incoming traffic
(just really does not make sense) so in this scenario you would not use
service-policy in.
Now perhaps you have inbound traffic from your ISP that you wish to treat
differently (differentiate - thus differentiated services - thus diffserv),
for example you wish to give higher priority through your network to SMTP as
oppossed to HTTP. You would create a class map to differentiate these
traffic types and then a policy map to colour or mark this traffic so that
upstream routers can treat the traffic accordingly.
You would then apply this policy as service-policy in.
The above is just one of many examples!! Hope that helps
Simon
-----Original Message-----
From: nobody@groupstudy.com [mailto:nobody@groupstudy.com]On Behalf Of
Ajinc
Sent: 18 February 2005 06:01
To: ccielab@groupstudy.com
Subject: CAR and qos query
Hi,All
CAR is often configured on interfaces at the edge of a network to limit
traffic into or out of the network.
this is a statement from the doc cd what does it mean by "edge of the
network" and can anybody explain where to configure each qos mechanisms.
this is always confucing.whether the service-policy command to be
configured with input or output keyword? Which interface?
Totally confucing isnt it ?
Regards
Aji.N.C
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