3Com MSR 50 Series Configuration Manual page 1658

1658 C 86: C M
HAPTER ONGESTION ANAGEMENT
Priority Queuing Configuration requirement
Configuration Example
As shown in the diagram, both Server and Host A send data to Host B through
Router A. Suppose Server sends key service data and Host A sends common
service data. Congestion may occur on interface Serial 2/0 resulting in packet loss
because the rate of the inbound interface Ethernet1/0 is larger than that of the
outgoing interface Serial 2/0 on Router A. The mission-critical service data has
priority when network congestion occurs.
Network diagram
Figure 469 Network diagram for PQ configuration
Router B Host B
S 1/0
Eth1 /1
PPP
Ethernet
2 M
Router A
S1 /1
Eth1/0
10 M
1.1.1.1/8
1.1.1.2/8 Ethernet
Host A Server
Configuration procedure
Configure on Router A:
# Configure ACLs for matching packets from Server and Host A respectively.
[RouterA] acl number 2001
[RouterA-acl-basic-2001] rule permit source 1.1.1.1 0.0.0.0
[RouterA] acl number 2002
[RouterA-acl-basic-2002] rule permit source 1.1.1.2 0.0.0.0
# Configure the priority-group so that the packets from Server enter the
high-priority queue of top for the PQ and those from Host A enter the low-priority
queue of bottom when the network experiences congestion. Set the maximum
queue length of the queue of top to 50 while that of the queue of bottom to 100.
[RouterA] qos pql 1 protocol ip acl 2001 queue top
[RouterA] qos pql 1 protocol ip acl 2002 queue bottom
[RouterA] qos pql 1 queue top queue-length 50
[RouterA] qos pql 1 queue bottom queue-length 100
# Apply the priority-group 1 on the interface Serial 1/1.
[RouterA] interface serial 1/1
[RouterA-Serial1/1] qos pq pql 1