Technical data

ServerIron ADX Advanced Server Load Balancing Guide 97
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Sample configurations
2
All ports on the ServerIron ADX are assigned to cache group 1 by default. Ports can be assigned to
any cache group (only one at a time) or removed from all cache groups. If a port is removed from all
cache groups, traffic entering on that port is not be redirected to a cache because rule 1 in this
example is not true.
Once the caches have been defined, they must be associated (bound) with a particular cache
group. The following CLI commands bind the cache servers shown in Figure 21 with a cache group.
ServerIronADX(config)# server cache-group 1
ServerIronADX(config-tc-1)# cache-name C1
ServerIronADX(config-tc-1)# cache-name C2
ServerIronADX(config-tc-1)# cache-name C3
POP using caching to minimize WAN costs
This example assumes a POP that belongs to an ISP. The RASs are actually remote access routers
for customer dial-in. The ISP does not pay the phone company for access to the RASs; the ISP
customers pay the phone company for this access. However, the ISP does pay for the WAN links
connecting the BARs to the Internet. The ISP wants to introduce caching to improve user response
time without the need to increase the size of the WAN links.
The ISP does not want to fill up the cache servers with content in its customer’s web sites. The ISP
wants to cache only the content on the other side of the BARs. The ISP wants only the traffic
entering from a RAS destined for a BAR to be cached. The ISP does not want to cache RAS-to-RAS
or BAR-to-RAS traffic.
In this example, the configuration requires more control than a global policy allows. Therefore, local
policies are used. Only one cache group, the default cache group 1, is required.
To configure the ServerIron ADX for this application, apply IP policies only to the BAR ports (4 and
5), define the caches, and place them in cache group 1. Here are the CLI commands for creating
this configuration.
ServerIronADX(config)# server cache-name C1 11.11.11.11
ServerIronADX(config)# server cache-name C2 11.11.11.12
ServerIronADX(config)# server cache-name C3 11.11.11.13
ServerIronADX(config)# ip policy 1 cache tcp 80 local
ServerIronADX(config)# int e 4
ServerIronADX(config-if-4)# ip-policy 1
ServerIronADX(config-if-4)# int e 5
ServerIronADX(config-if-5)# ip-policy 1
ServerIronADX(config-if-5)# ser cache-group 1
ServerIronADX(config-tc-1)# cache-name c1
ServerIronADX(config-tc-1)# cache-name c2
ServerIronADX(config-tc-1)# cache-name c3
Traffic entering from a BAR destined for a RAS is not cached because rule 2 (output redirection
enabled) is not true for the RAS ports. Traffic from RAS-to-RAS is not cached because rule 2 is false
in this case as well. Traffic from RAS-to-BAR is cached because both rules are true.
Both rules are true for BAR-to-BAR traffic as well. This type of traffic rarely, if ever, occurs. However,
if this type of traffic does occur and you do not want to cache the traffic, you cannot turn off the
output policy on the BAR ports or nothing will get cached. Instead, make rule 1 false by removing
the BAR ports from all cache groups. These ports are in the default cache group 1.
ServerIronADX(config)# int e 4
ServerIronADX(config-if-4)# no cache-group 1
ServerIronADX(config-if-4)# int e 5
ServerIronADX(config-if-5)# no cache-group 1