HP Hub & Switch Management for OV-UX - Manual (Page 58)

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Managing Switches
Configuration
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■ Providing an easy, flexible, less costly way to modify logical groups in
changing environments
■ Preserving current investment in equipment and cabling
■ Allowing administrators to “fine tune” the network
■ Providing independence from the physical topology of the network
VLANs make large networks more manageable. You can group users
according to some shared characteristic, such as a common business
function or a common protocol. A single switch may have several
independent VLANs within it.
Note: VLANs must be created with the device console.
Configuration - Device Features
The Device Features page (only found on switches) lets you set some or all
of these features:
■ Automatic Broadcast Control (ABC)
■ Multicast Filtering (IGMP)
■ Spanning Tree
Automatic Broadcast Control (ABC)
Automatic Broadcast Control (ABC) is a feature that controls broadcasts
through IP/IPX Broadcast Reduction. IP/IPX Broadcast Reduction reduces
the number of broadcasts propagated through the network.
Using ABC, the switch acts as a proxy server, replying to Address Resolution
Protocol (ARP) requests, Nearest Server Query (NSQ) requests, and
GetLocalTarget requests on behalf of the destination node. An ARP cache
(learned address table) is created for each subnet allowing the switch to
proxy reply with the resolved MAC address instead of forwarding the
requests out all ports. This limits the broadcasts within the switching
domain. The Service Advertising Protocol (SAP) table performs the same
function in an IPX network. By using these tables, the switch can resolve
addresses for any node in the network that it already knows about.
Routing Information Protocol. The switch also intercepts Routing
Information Protocol (RIP) and SAP broadcasts and forwards these only to
ports where routers and servers have been detected. This also reduces the
number of broadcasts on the network.