54-2
Catalyst 6500 Series Switch Software Configuration Guide—Release 8.7
OL-8978-04
Chapter 54 Configuring ASLB
Understanding How ASLB Works
Note
The 1000BASE-X interfaces are supported only on the LocalDirector 420 and 430; they
are not supported on the LocalDirector 410, 415, or 416.
–
Software—Cisco configuration version 3.2.x
•
The Catalyst 6500 series switch requirements are as follows:
–
Supervisor Engine 1 (or 1A) with the PFC
–
Supervisor engine software release 5.3(1)CSX or later releases
•
The participating routers are as follows:
–
Multilayer Switch Feature Card (MSFC)—With supervisor engine software release 5.4(1)CSX
or later releases, an MSFC in the Catalyst 6500 series switch can be used as a participating
router for ASLB. With earlier supervisor engine software releases, an internal MSFC
cannot
be
a participating router.
–
External MSFC—An MSFC in an externally attached Catalyst 6500 series switch can be used
as a participating router.
–
Multilayer Switch Module (MSM)—If the Catalyst 6500 series switch that you are using for
ASLB has an MSM, it can be used as a participating router for ASLB. The MSM in an externally
attached Catalyst 6500 series switch can also be used as a participating router.
–
Other Cisco routers can also be used as participating routers for ASLB.
Understanding How ASLB Works
Note
Refer to the
Cisco LocalDirector Installation and Configuration Guide,
Version 3.2, for an overview on
load balancing TCP/IP traffic.
These sections describe ASLB:
•
Layer 3 Operations for ASLB, page 54-3
•
Layer 2 Operations for ASLB, page 54-3
•
Client-to-Server Data Forwarding, page 54-4
•
Server-to-Client Data Forwarding, page 54-6
The LocalDirector is a secure, real-time, embedded operating system that intelligently load balances the
TCP/IP traffic across multiple servers. ASLB enables Catalyst 6500 series switches to cache the Cisco
LocalDirector load-balancing flows, accelerating the performance of the LocalDirector.
Note
The accelerated performance of the LocalDirector is achieved through the Catalyst 6500 series Layer 3
switching technology.
Figure 54-1
shows a network that uses the ASLB feature. You must connect the LocalDirector to the
switch with two links; one link connects to the same VLAN that the router is on and the other link
connects to the VLAN that the servers are on. In
Figure 54-1
, one LocalDirector link is connected to
VLAN 10, the router VLAN; the other link is connected to VLAN 20, the server VLAN.