Specifications

Chapter 5. Planning 133
VLAGs are also useful in multi-layer environments for both uplink and downlink
redundancy to any regular LAG-capable device, as shown in Figure 5-3.
Figure 5-3 VLAG with multiple layers
5.4.2 SAN and Fibre Channel redundancy
SAN infrastructure availability can be achieved by implementing certain
techniques and technologies. Most of them are widely used standards. This
section describes the most common technologies that can be implemented in an
IBM Flex System environment to provide high availability for a
SAN infrastructure.
In general, a typical SAN infrastructure consists of storage FCs, client FCs, and
SAN devices, such as SAN switches and the cables that connect them. The
potential failures in a SAN include port failures (both on the switches and in
storage), cable failures, and device failures.
LACP-capable
Switch
LACP-capable
Server
VLAG 2
VLAG
Peers
VLAG
Peers
VLAG 1
VLAG
Peers
VLAG 3 VLAG 4
ISLISL
ISL
LACP-capable
Routers
VLAG 5 VLAG 6
Layer 2/3 Border
Layer 2/3 Region
with multiple levels
Servers