Lucent Technologies 6000 - Manual (Page 514)

13-2 MAX 6000/3000 Network Configuration Guide
AppleTalk Routing
Introduction to AppleTalk routing
packet. A router can significantly reduce AppleTalk traffic over the WAN because it does not
forward broadcast traffic from one subnetwork to another, but stops it at the subnetwork port of
the router.
Zone multicasting is intended to prevent any node not in the destination zone for the lookup
from receiving the lookup packet. Any AppleTalk node responds only to NBP lookups for that
node’s zone name. In the example in the preceding paragraph, a router would convert the
Broadcast Request packet generated by the Lookup request to a Forward Request packet for
each network that contains nodes in the target zone specified by the Lookup request.
A bridge can filter directed traffic between two specific nodes but cannot filter broadcast or
multicast traffic, because there is no specific port that can be assigned to a multicast or
broadcast address. This means that although filters used with bridging can reduce the number
of AppleTalk packets sent to remote network segments, bridging does not reduce the number
of broadcast and multicast packets over these networks.
Providing dynamic startup information to local devices
In addition to routing services, the Lucent AppleTalk router provides startup information to
AppleTalk stations. As with other routed protocols, AppleTalk station, or node, addresses
consist of a unique network number/node combination. AppleTalk addresses are dynamically
assigned when a node starts up. In addition, the router provides an AppleTalk node with the
network cable range to which it is attached, and supplies zone name information.
AppleTalk zones and network ranges
AppleTalk zones and network ranges are configured in AppleTalk routers. Network numbers
are assigned to network segments, and must be unique within the internetwork. A network
range is a range of network numbers specified in the port descriptor of the router port and then
transmitted through RTMP to the other nodes of the network. Each of the numbers within a
network range can represent up to 253 devices.
AppleTalk zones
A zone is a multicast address containing an arbitrary subset of the AppleTalk nodes in an
internet. Each node belongs to only one zone, but a particular extended network can contain
nodes belonging to any number of zones. Zones provide departmental or other groupings of
network entities that a user can easily understand.
In the Lucent AppleTalk router, zone names are case-insensitive. Some routers regard zone
names as case-sensitive, however, so you should spell zone names consistently when you
configure multiple connections or routers.
Extended and nonextended AppleTalk networks
AppleTalk subnetworks are either nonextended or extended. Nonextended networks
theoretically allow up to 254 nodes. A nonextended network has one network number (not a
range) and one zone. Examples of nonextended networks are LocalTalk and AppleTalk
Remote Access (ARA) dial-up networks.