Enterasys Networks CSX6000 - Manual (Page 150)

USER’S GUIDE
150 CyberSWITCH
IP H OST O PERATING M ODE AND THE IP N ETWORK I NTERFACES
Only one network interface can be configured when the IP operating mode is host. The network
interface configuration is not much different from the others available in router mode except that
the following configuration items will not be asked:
•
Network Interface Type
• Network Interface Name
• IP RIP Send Control
U SING M ULTIPLE IP A DDRESSES
You may use multiple IP addressing for system backup and/or network flattening
implementations. A discussion of both follows.
Redundant Configurations for Backup
To implement a backup system, you will need two CyberSWITCHs with redundant configurations
and a Connection Services Manager (CSM).
LAN interfaces on the CyberSWITCH will have primary LAN and IP addresses and may optionally
have one or more secondary MAC and IP addresses. You can dynamically add secondary MAC and
IP addresses under the control of the CSM workstation.
Typically, you would use primary MAC and IP addresses when transmitting datagrams directly to
a particular CyberSWITCH node, and secondary MAC and IP addresses when transmitting
datagrams through the CyberSWITCH to other nodes. You would then use CSM to monitor
identically configured CyberSWITCH nodes on the same LAN. Should CSM notice some condition
which prevents one of the CyberSWITCH nodes from properly performing its function (for
example, “link down”), it will order the other CyberSWITCH node to take over the faulty node’s
duties. The other CyberSWITCH node does so by taking on the identity (the MAC and IP
addresses) of the faulty node.
Network Flattening
With IP networks, the total number of available IP addresses is a finite number, and that number is
rapidly diminishing. Hosts are typically assigned static addresses; they generally require extensive
local configuration in order to operate properly within their defined networks. To allow the IP
networks to become more easily and efficiently manageable, we suggest a network flattening
approach. Network flattening is a concept which can:
•
remove the address hierarchy from the network, and
• remove the requirements that all end nodes need to know the topology of the network (or the
address of the default router) to which they attach.
With network flattening, you may draw IP addresses for new nodes from remaining address space
from attached subnets. This more efficiently uses the network’s address space, since multiple
subnets may coexist on the same physical network. The following features help implement the
concept of network flattening:
• Proxy ARP
Hosts on flattened networks believe that any host they wish to reach is on a network directly
attached to them. When a local device on a flattened network is attempting to communicate