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Default queing stratagy inside the class-map

mahesh_kv3
Level 1
Level 1

hai,

cud any body tell about what will be the default Queing startegy in side class map which is configured inside a policy-map???

cud you please tell how it is configuring

Thanks in advance

Mahesh K V

8 Replies 8

Marwan ALshawi
VIP Alumni
VIP Alumni

default queueing is FIFO

first n first out

for example if u have a priority queueing configured in a class map

inside this calss map and this priority queue the queueing mechinisme will be FIFO

for default calss if u wanna know which contain ecery thing

called default cass

like

plicy-map policy1

class default-calss

fair-queue

please, if helpful Rate

Hi,

For serial interfaces at E1 (2.048 Mbps) and below, flow-based WFQ is used by default. When no other queueing strategies are configured, all other interfaces use FIFO by default.

fair-queue is for default-class only.

The default class of the policy map (commonly known as the class-default class) is the class to which traffic is directed if that traffic does not satisfy the match criteria of other classes whose policy is defined in the policy map.

http://www.cisco.com/en/US/docs/ios/12_2/qos/configuration/guide/fqos_c.html

HTH..

thanx for the fast response,

actually i had read that "shape command is used under the class map is used for class based queing "....amm I rt or not???

weather what will be the default queuing staratagy inside this??

ingress

policy-map POLICY-OUTPUT-SHORT-PIPE-PREC

class class-default

shape average 1619001

service-policy SUB-POLICY-OUT-SHORT-PIPE-PREC

cud u please clear me this as well???

shaping not related to queueing

take this example

if u have framerelay topology with hub and spoks

the hub with sub interfaces and the bandwidth is 1Mb

and one spok has 512K and other 128K

so if the hub send traffic with 1Mb then gonna be a batleneck

so with shaping u can

shap the traffic when go to spok 1 make the shap the subinterface bandwidth to 512 and so on

good luck

if helpful Rate

Yes!!! you can use shape coammnd under class map

Class based shaping is also possible like class based WFQ.

Again for default-class it is fair-queue.

So here you are doing shaping & default fair-queuing under one class.

HTH...

actually i had read that "shape command is used under the class map is used for class based queing "....amm I rt or not???

weather what will be the default queuing staratagy inside this??

ingress

policy-map POLICY-OUTPUT-SHORT-PIPE-PREC

class class-default

shape average 1619001

service-policy SUB-POLICY-OUT-SHORT-PIPE-PREC

cud u please clear me this as well???

Ingress?

For egress, when there was congestion at the shaper, actual queuing would depend on what your subordinate policy, SUB-POLICY-OUT-SHORT-PIPE-PREC, defined. In other words, behavior should be similar to SUB-POLICY-OUT-SHORT-PIPE-PREC applied to a link providing the bandwidth defined to the shaper.

If your SUB-POLICY-OUT-SHORT-PIPE-PREC was defined only as:

policy-map SUB-POLICY-OUT-SHORT-PIPE-PREC

then all the traffic would flow through SUB-POLICY-OUT-SHORT-PIPE-PREC's class class-default. Since you've not defined any other classes within POLICY-OUT-SHORT-PIPE-PREC, all its traffic flow through its class-default but that traffic would only, when its class-default shaper was congested, be pushed to SUB-POLICY-OUT-SHORT-PIPE-PREC class-default.

"fair-queue is for default-class only."

True for most, but there are a couple platforms, with certain hardware, that FQ is supported in non-default-class queues. E.g. 7500 VIPs, 6500/7600 FlexWAN or SIP-200.

Joseph W. Doherty
Hall of Fame
Hall of Fame

Default is FIFO except where the class-default default's to flow FQ (such as when implicit - i.e. not explicity defined as a class).

Unclear what you want to see "how" configured. The defaults would be obtained just by having the class defined to the policy without changing it with additional parameters.

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