Medianet Reference Guide - Cisco

Chapter 6
Medianet Management and Visibility Design Considerations
Cisco Network Analysis Module
bandwidth percent 4
dbl
class SCAVENGER-QUEUE
bandwidth percent 1
class class-default
bandwidth percent 25
dbl
!
~
!
interface GigabitEthernet3/1
description CONNECTION TO ME-WESTDIST-3 GIG1/13
no switchport
ip address 10.17.100.38 255.255.255.252
ip pim sparse-mode
load-interval 30
service-policy output 1P7Q1T-GIG3/1
!
~
!
interface GigabitEthernet3/3
description CONNECTION TO ME-WESTDIST-4 GIG1/2
no switchport
ip address 10.17.100.41 255.255.255.252
ip pim sparse-mode
load-interval 30
service-policy output 1P7Q1T-GIG3/3
!
~
Notice that the class-map definitions shown at the top of the configuration example are shared between
the policy maps. However, a unique policy map name is applied to each of the GigabitEthernet uplink
interfaces.
Referring back to Example 6-20, when a policer is applied to a queue, the bit rates of the data that
conform, exceed, and violate the policer committed information rate (CIR) are also displayed within the
show policy-map interface command. This information can provide a view of how much traffic is
currently being handled by a policed queue, and whether sufficient bandwidth has been provisioned on
the policer for the service classes handled by the queue. The final two highlighted sections in
Example 6-20 provide an aggregate byte count of the packets handled by the particular queue, as well as
the number of packets dropped because of insufficient buffer space on the queue. This holds for either
the priority queue defined via the priority command, or a class-based weighted fair queueing (CBWFQ)
defined via the bandwidth command. You can get an estimate of the overall data rate through a particular
queue by running the show policy-map interface command several times over fixed time intervals and
dividing the difference in byte count by the time interval.
Cisco Catalyst 3750G/3750E Series Commands
When QoS is enabled on the Cisco Catalyst 3750G/3750E Series switches with the mls qos global
command, egress queueing consists of four queues; one of which can be a priority queue, each with three
thresholds (1P3Q3T). The third threshold on each queue is pre-defined for the queue-full state (100
percent). Queue settings such as buffer allocation ratios and drop threshold minimum and maximum
settings are defined based on queue-sets applied across a range of interfaces; not defined per interface.
The Cisco Catalyst 3750G/3750E Series switches support two queue sets. Ports are mapped to one of the
two queue-sets. By default, ports are mapped to queue-set 1. The show platform port-asic stats drop
command allows you to view interface drops per queue on the switch port. Example 6-22 shows the
output from a NME-XD-24ES-1S-P switch module within a Cisco 3845 ISR, which runs the same code
base as the Cisco Catalyst 3750G.
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Medianet Reference Guide
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