Cabletron Systems CSX1000 Redundant Configurations for Backup, Network Flattening, Proxy ARP

USER’S GUIDE

IP HOST OPERATING MODE AND THE IP NETWORK INTERFACES

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

USING MULTIPLE IP ADDRESSES

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 VRA manager.

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 VRA 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 the VRA manager to monitor identically configured CyberSWITCH nodes on the same LAN. Should the VRA manager 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

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