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Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 13 Configuring CEF for PFC2 and PFC3A
Understanding How Layer 3 Switching Works
CEF for PFC2/PFC3A Examples
Figure 13-1
shows a simple IP CEF network topology. In this example, Host A is on the Sales VLAN
(IP subnet 171.59.1.0), Host B is on the Marketing VLAN (IP subnet 171.59.3.0), and Host C is on the
Engineering VLAN (IP subnet 171.59.2.0).
When Host A initiates an HTTP file transfer to Host C, PFC2/PFC3A uses the information in the FIB
and adjacency table to forward packets from Host A to Host C.
Figure 13-1
IP CEF Example Topology
Figure 13-2
shows a simple IPX CEF network topology. In this example, Host A is on the Sales VLAN
(IPX address 01.Aa), Host B is on the Marketing VLAN (IPX address 03.Bb), and Host C is on the
Engineering VLAN (IPX address 02.Cc).
When Host A initiates a file transfer to Host C, PFC2 uses the information in the FIB and adjacency table
to forward packets from Host A to Host C.
Source IP
Address
171.59.1.2
171.59.1.2
Host A
171.59.1.2
Host B
171.59.3.1
Host C
171.59.2.2
171.59.2.2
171.59.1.2:171.59.2.2
Data
171.59.3.1
171.59.2.2
171.59.1.2
Dd:Bb
Dd:Cc
Dd:Aa
Marketing
Engineering
Sales
Destination
IP Address
Rewrite Src/Dst
MAC Address
Destination
VLAN
MSFC
Subnet 1/Sales
MAC = Aa
MAC = Dd
MAC = Bb
MAC = Cc
Subnet 3/Marketing
Subnet 2/Engineering
Aa:Dd
171.59.1.2:171.59.2.2
Data
Dd:Cc
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