Reference Guide

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Microsoft Clustering
Microsoft Clustering is supported only on platform: e
Microsoft Clustering allows multiple servers using Microsoft Windows to be represented by one MAC
address and IP address in order to provide transparent failover or balancing. FTOS does not recognize
server clusters by default; it must be configured to do so.
Default Behavior
When an ARP request is sent to a server cluster, either the active server or all of the servers send a reply,
depending on the cluster configuration. If the active server sends a reply, the Dell Force10 switch learns the
active server’s MAC address. If all servers reply, the switch registers only the last received ARP reply, and
the switch learns one server’s actual MAC address (Figure 24-4); the virtual MAC address is never
learned.
Since the virtual MAC address is never learned, traffic is forwarded to only one server rather than the
entire cluster, and failover and balancing are not preserved (Figure 24-5).
Figure 24-4. Server Clustering: Multiple ARP Replies
VLAN 1
Client
Last ARP Reply
MAC
S1
Server1:
IP
S1
MAC
S2
IP
S2
Server2:
Source MAC: MAC
Cluster
Destination MAC: MAC
Client
Source IP: IP
S1
Source MAC: MAC
S1
Type: 0x0806
Pad
CRC
Ethernet Frame Header
ARP Reply
fnC0027mp
M
icrosoft Server Cluster:
IP
Cluster
MAC
Cluster
MAC
S3
IP
S3
Server3:
MAC
S4
IP
S4
Server4: