Cisco WS-C6506 Software Manual page 359

Chapter 14 Configuring MLS
Understanding IP Unicast Rewrite
Received IP unicast packets are (conceptually) formatted as follows:
Layer 2 Frame Header
Destination
MSFC MAC
After the switch rewrites an IP unicast packet, it is (conceptually) formatted as follows:
Layer 2 Frame Header
Destination
Destination B MAC MSFC MAC Destination B IP Source A IP n-1
Understanding IPX Unicast Rewrite
Received IPX packets are (conceptually) formatted as follows:
Layer 2 Frame Header
Destination
MSFC MAC Source A MAC n
After the switch rewrites an IPX packet, it is (conceptually) formatted as follows:
Layer 2 Frame Header
Destination
Destination B
MAC
Understanding IP Multicast Rewrite
Received IP multicast packets are (conceptually) formatted as follows:
Layer 2 Frame Header
Destination Source
1
Group G1 MAC Source A MAC
1. In this example, Destination B is a member of Group G1.
OL-8978-04
Layer 3 IP Header
Source Destination
Source A MAC Destination B IP
Layer 3 IP Header
Source Destination
Layer 3 IPX Header
Source Checksum/
IPX Length/
Transport Control
Layer 3 IPX Header
Source Checksum/
IPX Length/
Transport Control
MSFC MAC n+1
Layer 3 IP Header
Destination
Group G1 IP
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
Understanding How Layer 3 Switching Works
Source TTL Checksum
Source A IP n
Source
Destination Net/
Node/
Socket
Destination B IPX
Destination Net/
Node/
Socket
Destination B IPX
Source TTL
Source A IP n
Data FCS
calculation1
Data FCS
TTL Checksum
calculation2
Data FCS
Source Net/
Node/
Socket
Source A IPX
Data FCS
Source Net/
Node/
Socket
Source A IPX
Data FCS
Checksum
calculation1
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