10-6
Cisco 10000 Series Router Quality of Service Configuration Guide
OL-7433-09
Chapter 10 Overhead Accounting
Overhead Accounting and Hierarchical Policies
Overhead Accounting and Hierarchical Policies
In hierarchical policies, you can enable overhead accounting for shaping and bandwidth on top-level
parent policies, middle-level child policies, and bottom-level child policies. If you enable overhead
accounting on a:
•
Parent class-default class, you are not required to enable accounting on a child traffic class that does
not contain the
bandwidth
or
shape
command.
•
Child policy, then you must enable overhead accounting on the parent policy.
The parent and child classes must specify the same encapsulation type when enabling overhead
accounting and configuring an offset using the
user-defined
offset
[
atm
] command option.
Table 10-2
summarizes the configuration requirements for overhead accounting. For example, if
overhead accounting is currently enabled for a parent policy, then accounting can be disabled or enabled
on a child policy.
AAL5 MUX plus PPPoA
10
8-byte AAL5 t 2-byte protocol ID (0x0021)
AAL5 SNAP plus 1483
18
8-byte AAL5 t 3-byte LLC header
(0xAAAA03) + 3-byte OUI (0x0080c2) + 2-byte
protocol ID (0x0007) + 2-byte PAD (0x0000)
AAL5 SNAP plus PPPoA
12
8-byte AAL5 t 3-byte LLC header (0xFEFE03)
+ 1-byte protocol ID (0xCF)
PPPoE
6
1-byte version/type (0x11) + 1-byte code (0x00) +
2-byte session ID + 2-byte length
qinq
22
6-byte destination MAC a 6-byte source MAC
a 2-byte protocol ID (0x8100) + 2-byte
VID/CFI/PR 2-byte protocol ID + 2-byte
inner tag + 2-byte length or type
Table 10-1
Overhead Calculation (continued)
Encapsulation Type
Number of Bytes
Description
Table 10-2
Overhead Accounting Configuration Requirements
Policy Map or Class
Current Configuration
Configuration Requirement
Parent
Enabled
Enabled on child policy
Child
Enabled
Enabled on parent policy
Child class
Enabled
Enabled on all classes in the child policy map,
except priority classes with policing
Child class (nonpriority
without policing)
Disabled
Disabled on all classes in the child policy map
Child class (priority with
policing)
Disabled
Disabled or enabled on all nonpriority classes
in the child policy map
