3Com 4800G Series, Configuration Manual

Page: 433 / 1246

Configuring RIPng Basic Functions 433
Figure 141 IPv6 prefix RTE format
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IPv6 prefix: Destination IPv6 address prefix.
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Route tag: Route tag.
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Prefix len: Length of the IPv6 address prefix.
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Metric: Cost of a route.
RIPng Packet Processing
Procedure
Request packet
When a RIPng router first starts or needs to update some entries in its routing
table, generally a multicast request packet is sent to ask for needed routes from
neighbors.
The receiving RIPng router processes RTEs in the request. If there is only one RTE
with the IPv6 prefix and prefix length both being 0, and with a metric value of 16,
the RIPng router will respond with the entire routing table information in response
messages. If there are multiple RTEs in the request message, the RIPng router will
examine each RTE, update its metric, and send the requested routing information
to the requesting router in the response packet.
Response packet
The response packet containing the local routing table information is generated
as:
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A response to a request
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An update periodically
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A trigged update caused by route change
After receiving a response, a router checks the validity of the response before
adding the route to its routing table, such as whether the source IPv6 address is
the link-local address, whether the port number is correct. The response packet
failed the check will be discarded.
Protocols and Standards
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RFC2080: RIPng for IPv6
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RFC2081: RIPng Protocol Applicability Statement
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RFC2453: RIP Version 2
Configuring RIPng
Basic Functions
In this section, you are presented with the information to configure the basic
RIPng features.
You need to enable RIPng first before configuring other tasks, but it is not
necessary for RIPng related interface configurations, such as assigning an IPv6
address.
IPv6 prefix (16 octets)
Route tag Prefix length Metric
0 7 15 31