Network address translation options, Configuring url-based web cache redirection – Nortel Networks WEB OS 212777 User Manual
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Web OS 10.0 Application Guide
Chapter 15: Content Intelligent Switching
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212777-A, February 2002
Network Address Translation Options
URL-based WCR supports three types of Network Address Translation (NAT): No NAT, Half
NAT, and Full NAT.
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No NAT
In this NAT method, the traffic is redirected to the Web cache with the destination MAC
address replaced by the MAC address of the cache. The destination IP address remains
unchanged, and no modifications are made to the IP address or the MAC address of the
source or origin server. This works well for transparent cache servers, which process traf-
fic destined to their MAC address but with the IP address of some other device.
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Half NAT
In this most commonly used NAT method, the destination IP address is replaced by the IP
address of the Web cache, and the destination MAC address is replaced by the MAC
address of the Web cache. Both the IP address and the MAC address of the source remain
unchanged.
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Full NAT
In this NAT method, the source IP address and the source MAC address are replaced by
the IP address and MAC address of the Web cache. This method works well for proxy
cache servers.
Configuring URL-Based Web Cache Redirection
To configure URL-based Web Cache Redirection (WCR), perform the following steps:
1.
Before you can configure URL-based WCR, configure the switch for basic Server Load
Balancing (SLB) with the following tasks:
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Assign an IP address to each of the real servers in the server pool.
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Define an IP interface on the switch.
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Define each real server.
For information on how to configure your network for SLB, see
2.
Configure the switch to support basic WCR.
For information on WCR, refer to