13-12
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter 13
Configuring IP over ATM
Policy-Based Routing
•
The following commands are not supported:
–
set ip default next-hop
–
set ip default interface
•
When you configure a policy to rewrite precedence with a next hop interface, the precedence is
rewritten only when the packet flows via the supported PBR path. If the next-hop is not accessible,
the original precedence is retained since the packet flows via DBR (destination based routing).
Figure 13-4
illustrates the supported PBR path for IP packet flow on the Catalyst 8540 MSR and the
Catalyst 8540 CSR.
Figure 13-4 IP Packet Flow for PBR
MATCH ON
ACL
ACL TYPE
MATCH ON
LENGTH
PRESENT?
NEXT
SEQUENCE
PRESENT?
ROUTE-MAP
GRANT FLAG?
DBR PATH
DBR PATH
DBR PATH
PBR PATH
MATCH ON
LENGTH
NEXT
SEQUENCE
PRESENT?
HIT
PERMIT
PERMIT
MISS
DENY
DENY
NO
NO
NO
YES
YES
MATCH
NO MATCH
PACKET
(WHEN NO ACL
CLASSIFICATION)
IP PACKET
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