Cisco Wide Area Application Engine 612 Instrukcja Użytkownika Pobierz pdf (Strona 31)

Interception Techniques and Protocols 105

Because PBR evaluates only trafﬁc entering an interface, the route map entries are conﬁgured

on both the client and server-facing interfaces. This is the equivalent of using only inbound

redirection with WCCPv2. The set ip next-hop command in the route map is conﬁgured

with the IP address of the WAE. By default, PBR does not validate to availability of the IP

address speciﬁed as the next-hop address. As long as the next-hop address exists in the

routing table, the route map entry will be applied. On software-based platforms (ISR, and

so forth), Cisco Service Assurance Agent (SAA) can be used to track the availability of the

next-hop IP address. If the next-hop address becomes unreachable, trafﬁc matching the

route map entry is forwarded normally using the routing table. However, this capability

does not currently exist on hardware-based platforms.

Other difference between WCCPv2 and PBR is that PBR does not perform automatic

load distribution and failover when multiple WAEs exist. The ﬁrst next hop IP address

conﬁgured in the route map is used until it becomes unavailable. Only at that point is trafﬁc

redirected to a secondary next hop IP address in the route map. Chapters 5 and 6 provide

examples of PBR deployments that include next hop availability tracking using SAA and

load distribution among multiple WAEs.

Inline Interception

An alternative to the various off-path interception mechanisms is to place the WAE

physically inline between two network elements, such as a WAN access router and local-

area network (LAN) switch. Figure 4-13 shows a basic topology with the WAE deployed

physically inline.

Figure 4-13 WAE Physical In-Path Deployment

ip address 10.10.20.1 255.255.255.0

end

Example 4-20 PBR Conﬁguration (Continued)

inlinePort 1/0/wan

inlinePort 1/0/lan

WAN

1 2 ... 26 27 28 29 30 31 32 33 34 35 36 ... 40 41

Brak uwag

Cisco Wide Area Application Engine 612 Instrukcja Użytkownika Strona 31