Nortel Networks WEB OS 212777 - Manual (Page 346)

Web OS 10.0 Application Guide
346 n Chapter 13: Firewall Load Balancing
212777-A, February 2002
Advanced FWLB Concepts
Free-Metric FWLB
Free-metric FWLB allows to you use load-balancing metrics other than hash , such as
leastconns , roundrobin , minmiss , response , and bandwidth for more versatile
FWLB.
The free-metric method uses the Return to Sender (RTS) option. RTS can be used with basic
FWLB or four-subnet FWLB networks.
Free-Metric with Basic FWLB
For this example, review the basic FWLB example network.
Figure 13-8 Basic FWLB Example Network
To use free-metric FWLB in this network, the following configuration changes are necessary.
1. On the clean-side Web switch, enable RTS on the ports attached to firewalls (ports 2 and 3).
2. On the dirty-side Web switch, remove the redirection filter from the ports attached to the
real servers (ports 4 and 5), but make sure filter processing is enabled.
>> # /cfg/slb/port 2/rts enable
>> # ../port 3/rts enable
>> # ../port 4/rem 224
>> # filt ena
>> # ../port 5/rem 224
>> # filt ena
"Dirty" Side "Clean" Side
Internet
Firewall 1
Firewall 2
Servers
Web Switch 1
IF1: 192.16.12.1
Web Switch 2
IF1: 20.1.1.1
Virtual Server:
20.1.1.10
20.1.1.2
20.1.1.3
Dirty Side:
10.1.2.10
IF2: 10.1.1.1
IF3: 10.1.2.1 IF2: 10.1.3.1
IF3: 10.1.4.1
Dirty Side:
10.1.1.10
Clean Side:
10.1.4.10
Clean Side:
10.1.3.10
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