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On an extended network, such as EtherTalk 2.0, you can assign any contiguous range of unique 16-bit network numbers between 1 and 65,279 to a network segment. Each network number within the assigned range can support up to 253 nodes (node numbers 0, 254, and 255 are reserved). Each node on an extended network uses the combination of network and node number as its unique identifier. This scheme increases the theoretical limit of the number of nodes per network to greater than 16 million.
On extended networks, the first time a node is started up it requests a node address from the underlying data link. The node ID part of this address is chosen at random, and the network number part is chosen from the reserved startup range (65,280 through 65,534).
If the node address selected is in use, the node chooses different node numbers until it finds an unused one. Using this startup address, the node can communicate with the router and can acquire a valid network number from the configured range for the network.
If the node has been previously started on the extended network, it uses the same address when it attempts to reconnect to the network. If another node is using that address, the node again chooses different node numbers until it finds an unused one.
NOTE: A nonextended network can communicate with an extended network through an AppleTalk router. Refer to Addressing for Nonextended Networks for more information.
Extended networks require a network range and a zones list .
A network range is a contiguous range of valid network numbers. The size of the network range you assign determines the maximum number of AppleTalk devices on that network; for example, an extended network with the range 1,001 to 1,010 could support up to 10 x 253, or 2,530, nodes. The only hard-coded limit to the size of a network range is 65,279; however, for optimal performance, you should specify the smallest range that suits your needs. A wider range unnecessarily consumes network numbers.
All AppleTalk routers connected to a network must use the same range for that network, and no other network within that internetwork can use that range or any number contained within it.
A zones list can contain up to 255 zone names. One zone is configured as the default zone . All AppleTalk routers on a network must agree about the zones list.
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