Cisco Wide Area Application Engine 612 Manual de usuario descargar pdf (Pagina 29)

Interception Techniques and Protocols 103

The L2 forwarding and mask assignment options are conﬁgured as part of the service

deﬁnition in WAAS. These capabilities are advertised to the WCCPv2-enabled IOS devices

when a WAE ﬁrst joins the service group. Example 4-18 demonstrates the WAAS WCCPv2

conﬁguration with the L2 forwarding and mask assignment options.

Unlike the hash algorithm used with hash assignment, the mask used for mask assignment

is conﬁgurable. As mentioned previously in this chapter, the default mask used by WAAS

is 0x1741. The default mask is applied to the source IP address for service group 61 and is

applied to the destination IP address for service group 62. Depending on the IP addressing

used in your environment, you may want to change the default mask to provide for better

load distribution among the WAEs in a service group. The default mask is changed on the

WAE using the following command syntax:

wccp tcp-promiscuous mask src-ip-mask

0-4261412864

The conﬁgured mask is applied to service group 61. Service group 62 mirrors the

conﬁguration and cannot be conﬁgured separately. Example 4-19 shows using a non-

default mask with WCCPv2.

Policy-Based Routing

Policy-based routing (PBR) provides another alternative for transparent interception with

WAAS, although it is less commonly deployed than WCCPv2 and inline interception. PBR

can be used in situations where customers are unable to run WCCPv2 or inline interception.

PBR can also be used in conjunction with a content switch, such as the Cisco Application

Control Engine (ACE), to provide transparent interception and load balancing for large-

scale data center deployments. Deployment examples using PBR for transparent

interception are provided in Chapters 5 and 6.

Example 4-18 WCCP Conﬁguration Using L2 Forwarding and Mask Assignment

wccp router-list 1 10.10.20.1

wccp tcp-promiscuous router-list-num 1 l2-redirect mask-assign

wccp version 2

Example 4-19 Custom WCCP Mask

wccp router-list 1 10.10.20.1

wccp tcp-promiscuous mask src-ip-mask 0xf

wccp tcp-promiscuous router-list-num 1 l2-redirect mask-assign

wccp version 2

l2-redirect mask-assign

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Cisco Wide Area Application Engine 612 Manual de usuario Pagina 29