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AppleTalk Routes
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Important
Considerations
Before administering AppleTalk routes, review the following guidelines
and considerations:
■
The RTMP table supports a maximum of 514 entries.
■
AppleTalk supports a maximum distance of 15 hops.
■
A hop count of 0 represents a network that is directly connected to
the router.
■
When an AppleTalk router starts up on the network, the first entries in
its routing table are the network numbers to which it is directly
attached.
■
Node numbers are dynamically assigned and often change when the
router restarts.
■
Each 16 bit number within a network range is capable of supporting
253 network nodes.
■
When a router receives an RTMP packet that contains a routing entry
currently not in its table, the router adds the entry to its routing table,
and increments the route’s distance (hop count) by 1.
■
When a network is removed from the RTMP table (whether manually
or though the aging process), the router also scans the Zone
Information Table (ZIT), and removes ZIT entries that contain the
deleted network number.
■
If the Zone Information Table contains an entry whose network
number range is not in the RTMP table, the router then concludes that
the network is no longer on the Internet and deletes the network’s
ZIT entry.
■
An overburdened network with many routers can prevent some
routers from sending RTMP updates every 10 seconds. Because
routers begin to age out routes after the loss of 2 successive RTMP
updates, the failure for RTMP packets to arrive may result in
unnecessary route changes, known as
route flapping . For this reason,
keep network segments to a reasonable size.