Cisco Cisco Web Security Appliance S170 사용자 가이드
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I R O N P O R T A S Y N C O S 6 . 5 F O R W E B U S E R G U I D E
The Web Cache Communication Protocol allows 257 different service IDs. AsyncOS allows
you to create a dynamic WCCP service for each possible service ID. However, in typical
usage, most users create one or two WCCP services, where one is a standard service and the
other a dynamic service.
you to create a dynamic WCCP service for each possible service ID. However, in typical
usage, most users create one or two WCCP services, where one is a standard service and the
other a dynamic service.
When you create a WCCP service of any type, you must also specify the following
information:
information:
• Assignment method. For more information, see “Working with the Assignment Method”
• Forwarding and Return method. For more information, see “Working with the Forwarding
If you enable IP spoofing on the appliance, you must create two WCCP services. For more
information, see “IP Spoofing when Using WCCP” on page 497.
information, see “IP Spoofing when Using WCCP” on page 497.
Working with the Assignment Method
WCCP defines the assignment method as the method by which redirected packets are
distributed between web proxies. In this case, between one or more Web Security appliances.
The assignment method determines how the router performs load balancing of packets among
multiple Web Security appliances.
distributed between web proxies. In this case, between one or more Web Security appliances.
The assignment method determines how the router performs load balancing of packets among
multiple Web Security appliances.
You configure the assignment method for a WCCP service in the Load-Balancing Method field
under the Advanced section when you create or edit a WCCP service.
under the Advanced section when you create or edit a WCCP service.
You can configure WCCP services to use either of the following assignment methods:
• Mask. This method relies on masking to make redirection decisions. WCCP routers make
decisions using hardware in the router. This method can be very efficient because the
hardware redirects the packets. You might want to choose mask to reduce CPU cycles on
the router which can increase router performance. You can only use mask with WCCP
routers that support mask assignment.
hardware redirects the packets. You might want to choose mask to reduce CPU cycles on
the router which can increase router performance. You can only use mask with WCCP
routers that support mask assignment.
Note — AsyncOS chooses the mask value to use with the router. You cannot configure the
mask value.
mask value.
• Hash. This method relies on a hash function to make redirection decisions. You might
want to use Hash when the WCCP router does not support masking.
You can also configure a WCCP service to allow either mask or hash load balancing. When a
WCCP service allows both mask and hash, AsyncOS communicates with the router to
determine whether or not the router supports mask. If the router supports mask, then AsyncOS
uses masking in the service group, if the router does not support mask, then AsyncOS uses
hashing in the service group.
WCCP service allows both mask and hash, AsyncOS communicates with the router to
determine whether or not the router supports mask. If the router supports mask, then AsyncOS
uses masking in the service group, if the router does not support mask, then AsyncOS uses
hashing in the service group.