266 Chapter 10 BCM50 Utilities
NN40020-600NN40020-600
Trace Route
You can use Trace Route to measure round-trip times to all hops along a route. This helps you to
identify bottlenecks in the network. Trace Route uses the IP TTL (time-to-live) field to determine
router hops to a specific IP address. A router must not forward an IP packet with a TTL field of 0
or 1. Instead, a router discards the packet and returns to the originating IP address an ICMP time
exceeded message.
Traceroute sends an IP datagram with a TTL of 1 to the selected destination host. The first router
to handle the datagram sends back a time exceeded message. This message identifies the first
router on the route. Trace Route then transmits a datagram with a TTL of 2.
The second router on the route returns a time exceeded message until all hops are identified. The
Traceroute IP datagram has a UDP Port number not likely to be in use at the destination (normally
greater than 30,000). The destination returns a port unreachable ICMP packet. The destination host
is identified.
To perform a trace route
1Click the Administration tab.
2Open the Utilities folder, and then click Trace Route.
The Trace Route panel opens.
3In the Maximum Number of Hops field, enter the maximum number of hops on the route.
The default is 5 hops.
4In the Address field, enter the IP address of the element for which you want to perform a trace
route.
5Click the Trace Route button.
The results are displayed in the Results area.
Ethernet Activity
The Ethernet Activity panel is a utility that you can use to view ethernet activity in the BCM50
system.
Note: Establishing a PPP link over a modem make take some time. If the Ping
utility times out before the modem call can be established, click the Ping button
again.