Ripng Packet Format - 3Com MSR 50 Series Configuration Manual

1070 C 65: IP 6 RIP
HAPTER V

RIPng Packet Format

C
NG ONFIGURATION
Each RIPng router maintains a routing database, including route entries of all
reachable destinations. A route entry contains the following information:
Destination address: IPv6 address of a host or a network.
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Next hop address: IPv6 address of a neighbor along the path to the destination.
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Egress interface: Outbound interface that forwards IPv6 packets.
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Metric: Cost from the local router to the destination.
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Route time: Time that elapsed since a route entry is last changed. Each time a
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route entry is modified, the routing time is set to 0.
Route tag: Identifies the route, used in routing policy to control routing
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information. For information about routing policy, refer to
Configuration" on page
Basic format
A RIPng packet consists of a header and multiple Route Table Entries (RTEs). The
maximum number of RTEs in a packet depends on the MTU of the sending
interface.
Figure 311 shows the packet format of RIPng.
Figure 311 RIPng basic packet format
0
Command
Command: Type of message. 0x01 indicates Request, 0x02 indicates Response.
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Version: Version of RIPng. It can only be 0x01 currently.
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RTE: Route table entry, 20 bytes for each entry.
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RTE format
There are two types of RTE in RIPng.
Next hop RTE: Defines the IPv6 address of a next hop
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IPv6 prefix RTE: Describes the destination IPv6 address, route tag, prefix length
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and metric in the RIPng routing table.
Figure 312 shows the format of the next hop RTE:
Figure 312 Next hop RTE format
0
Must be zero
991.
7 15
Version
Route table entry 1 (20 octets)
Route table entry n (20 octets)
7 15
IPv6 next hop address (16 octets)
"Routing Policy
Must be zero
Must be zero
31
31
0xFF