274
Chapter 7
Multi-Layer Switching (MLS)
F I G U R E 7 . 6
Frame modification
Subsequent Packets
Once the candidate and enable packets have been identified and a shortcut,
or flow cache, has been established, subsequent packets are forwarded by the
switch to the destination without the use of the router. Because the MLS-SE
has the capability to rewrite the frames, it can make the necessary modifica-
tions and forward the frame directly to the destination host.
VLAN10
HostA
00-f3-81-01-02-b3
HostD
00-f3-81-03-f3-b1
VLAN50
FE0/0.10
08-01-fb-05-06-4f
08-01-fb-05-6e-51
FE0/0.50
Switch1
RouterA
08-01-fb-05-06-4f
10
00-f3-81-01-02-b3
Ethernet header
Source MAC
Destination
MAC
Initial Header Information
VLAN
assignment
value
ISL header
00-f3-81-03-f3-b1
50
08-01-fb-05-6e-51
Ethernet header
Source MAC
Destination
MAC
VLAN
assignment
value
ISL header
Copyright ©2000 SYBEX , Inc., Alameda, CA
www.sybex.com