Qos Policy Configuration Examples; Simple Qos On Physical Interface Policy - Enterasys Security Router X-PeditionTM User Manual

QoS Policy Configuration Examples

Table 12-3 Overhead on IPSec Tunnels
Tunnel Type Mode
Tunnel ESP
Tunnel AH
Tunnel ESP
As an example, tunnels with ESP and 3DES encoding will add 44 bytes (or more) overhead.
Padding for 3DES may add eight more bytes. Calculate the shaper rate with this formula:
ShaperRate = LineRate * ( 1 - OverHead/(OverHead +AvgPktSize))
The table below summarizes the shaper rate as a percentage from the line rate for different
average packet sizes and tunnel modes. The larger the packet, the lesser tunnel overhead effect.
Table 12-4 Tunnel Shaper Rates
Packet Size
64
128
380
1084
QoS Policy Configuration Examples

Simple QoS on Physical Interface Policy

The following QoS example configures Class1 with these characteristics on the Serial 1 /1
interface: a minimum of 200 Kbps of bandwidth are expected to be delivered to this class in the
event of congestion, and the queue reserved for this class can enqueue 40 packets before tail drop
is employed to handle additional packets.
Class2 is specified with these characteristics: a minimum of 300 Kbps of bandwidth are expected to
be delivered to this class in the event of congestion. For congestion avoidance, RED packet drop is
used, not tail drop. The default class is configured with a maximum of 20 packets per queue which
are enqueued before tail drop is used to handle additional packets.
Begin by creating Class1 and Class2 and matching their respective parameters:
XSR(config)#class-map class1
XSR(config-cmap<class1)#match access-group 136
XSR(config-cmap<class1)#exit
XSR(config)#class-map class2
XSR(config-cmap<class2>)#match ip precedence 2
Create the policy map:
XSR(config)#policy-map policy1
XSR(config-pmap<policy1>)#class class1
XSR(config-pmap-c<class1>)#bandwidth 200
12-24 Configuring Quality of Service
Tunnel
IP
Header
Tunnel 20 bytes
Transport NA
Transport NA
TunnelAH Tunnel ESP
0.592593 0.592593
0.744186 0.744186
0.896226 0.896226
0.958801 0.958801
AH (HMAC) ESP+3DES
NA 24 bytes
24 bytes NA
NA 24 bytes
TransAH TransESP
0.727273 0.727273
0.842105 0.842105
0.940594 0.940594
0.977099 0.977099
Total
Overhead
44 bytes
24 bytes
24 bytes