42-6
Catalyst 6000 Family Software Configuration Guide—Releases 6.3 and 6.4
78-13315-02
Chapter 42 Configuring ASLB
Understanding How ASLB Works
Server-to-Client Data Forwarding
Figure 42-3
shows how data is forwarded from the servers to the clients.
Table 42-4
lists the sequence
of events, and
Table 42-5
lists the Layer 3 table entries.
The traffic from the servers to the router or client devices works in the same manner, but in the reverse
direction, as the data forwarding described in the
“Client-to-Server Data Forwarding” section on
page 42-4
with the exception that the LocalDirector put its own MAC address as the source of the packet
for all packets going to the router. For the traffic in the client-to-server direction, the source MAC
address of the packet was unmodified.
Figure 42-3 Server to Client ASLB Packet Flow
Table 42-4 Server to Client ASLB Packet Flow
Path
Number
VLAN
MAC
Destination
Address
MAC Source
Address
IP Destination
Address
IP Source
Address
Flags
Action
1
20
Router MAC
1
1.
This MAC address has an Xtag value of 14 in the Layer 2 table for this packet’s VLAN.
Server MAC
2
2.
MAC address of the server that the LocalDirector selected.
CIP
3
3.
CIP = client’s IP address.
VIP
4
4.
VIP = virtual-IP address.
SYN
Candidate entry in
Layer 3 table
2
10
Router MAC
LocalDirector
MAC
1
CIP
VIP
-
Enabler packet
3—N
20
Router MAC
1
Server MAC
CIP
VIP
-
Full ASLB MLS
entry created
N + 1
20
Router MAC
1
Server MAC
CIP
VIP
FIN/RST
Path 1 redirect
N +2...
10
Router MAC
LocalDirector
MAC
1
CIP
VIP
FIN/RST
Path 2
P
R
P
A
Path 1
Path 2
Path 3
P
B
P
M
P
L
P
K
Catalyst 6500
series switches
LocalDirector
Clients
Server pool
S1
S2
S3
VLAN 10
VLAN 20
28064