2-2
Figure 2-1
Traceroute process
Device A
Hop Limit=1
Hop Limit exceeded
Hop Limit=2
Hop Limit exceeded
Hop Limit=n
UDP port unreachable
Device B
Device C
Device D
As
Figure 2-1
shows, the traceroute process is as follows:
z
The source sends an IP datagram with the Hop Limit of 1.
z
If the first hop device receiving the datagram reads the Hop Limit of 1, it will discard the packet and
return an ICMP timeout error message. Thus, the source can get the first device’s address in the
route.
z
The source sends a datagram with the Hop Limit of 2 and the second hop device returns an ICMP
timeout error message. The source gets the second device’s address in the route.
z
This process continues until the datagram reaches the destination host. As there is no application
using the UDP port, the destination returns a “port unreachable” ICMP error message.
z
The source receives the “port unreachable” ICMP error message and understands that the packet
has reached the destination, and thus determines the route of the packet from source to
destination.
Table 2-2
Traceroute IPv6
To do…
Use the command…
Remarks
Traceroute IPv6
tracert ipv6
[
-f
first-ttl
|
-m
max-ttl
|
-p
port
|
-q
packet-num
|
-w
timeout
]*
remote-system
Required
Available in any view
IPv6 TFTP
IPv6 supports TFTP (Trivial File Transfer Protocol). As a client, the device can download files from or
upload files to a TFTP server. For details about TFTP, see
FTP-SFTP-TFTP
.
Configuration preparation
Enable TFTP on the TFTP server and specify the path to download or upload files. For specific
operations, refer to TFTP server configuration specifications.
IPv6 TFTP configuration
You can use the commands listed in
Table 2-3
to download files from a TFTP server or upload files to a
TFTP server.
