LevelOne GTL-2691 - Manual (Page 627)

C HAPTER 18 | General IP Routing
Address Resolution Protocol
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returning an “ICMP port unreachable” message. If the timer goes off
before a response is returned, the trace function prints a series of
asterisks and the “Request Timed Out” message. A long sequence of
these messages, terminating only when the maximum timeout has
been reached, may indicate this problem with the target device.
◆ The same link-local address may be used by different interfaces/nodes
in different zones (RFC 4007). Therefore, when specifying a link-local
address, include zone-id information indicating the VLAN identifier after
the % delimiter. For example, FE80::7272%1 identifies VLAN 1 as the
interface.
W EB I NTERFACE
To trace the route to another device on the network:
1. Click IP, General, Trace Route.
2.
Specify the target device.
3. Click Apply.
Figure 381: Tracing the Route to a Network Device
A
DDRESS
R
ESOLUTION
P
ROTOCOL
If IP routing is enabled (page 649 ), the router uses its routing tables to
make routing decisions, and uses Address Resolution Protocol (ARP) to
forward traffic from one hop to the next. ARP is used to map an IP address
to a physical layer (i.e., MAC) address. When an IP frame is received by
this router (or any standards-based router), it first looks up the MAC
address corresponding to the destination IP address in the ARP cache. If
the address is found, the router writes the MAC address into the
appropriate field in the frame header, and forwards the frame on to the