3Com 4007, Руководство по внедрению, Страница: 383 / 684

Routing Information Protocol (RIP)
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Poison Reverse is essentially another layer of protection against
advertising reverse routes.
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When you enable (default mode) Poison Reverse, the Multilayer
Switching Module advertises reverse routes in updates, but it sets the
metrics to 16 (infinity). Setting the metric to infinity breaks the loop
immediately when two routers have routes that point to each other.
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When you disable Poison Reverse, such reverse routes are not
advertised.
You can disable Poison Reverse because it augments what Split Horizon
already does, and it puts additional information that you may not need
into RIP updates.
Advertisement
Address
The module uses the advertisement address specified to advertise routes
to other stations on the same network. The module uses this address for
sending updates.
Each interface that you define initially uses the default broadcast address
(255.255.255.255) as the advertisement address. If you change the
broadcast address, the address that you specify becomes the new RIP
advertisement address.
Effects and Consequences
After you add an advertisement address, you cannot subsequently
change the broadcast address.
RIP-1 Versus RIP-2 Like RIP-1, RIP-2 allows the module to dynamically configure its own
routing table. RIP-2 is much more flexible and efficient than RIP-1,
however, because RIP-2 advertises using the multicast method, which can
advertise to a subset of the network (RIP-1 uses the broadcast method,
which advertises to the whole network). RIP-2 can do this because it
includes a subnet mask in its header.
If your module receives a RIP-2 packet, your module puts the route into
the routing table with the subnet mask that was advertised.