Supported Platforms
Displaying Multicast Path Information
To display information about a multicast path from a source to the J Series device, enter the mtrace from-source command with the following syntax:
Table 1 describes the mtrace from-source command options.
Table 1: CLI mtrace from-source Command Options
Option | Description |
|---|---|
source host | Traces the path to the specified hostname or IP address. |
extra-hops number | (Optional) Sets the number of extra hops to trace past nonresponsive devices. Specify a value from 0 through 255. |
group address | (Optional) Traces the path for the specified group address. The default value is 0.0.0.0. |
interval seconds | (Optional) Sets the interval between statistics gathering. The default value is 10. |
max-hops number | (Optional) Sets the maximum number of hops to trace toward the source. Specify a value from 0 through 255. The default value is 32. |
max-queries number | (Optional) Sets the maximum number of query attempts for any hop. Specify a value from 1 through 32. The default value is 3. |
response host | (Optional) Sends the response packets to the specified hostname or IP address. By default, the response packets are sent to the J Series device. |
routing-instance routing-instance-name | (Optional) Traces the routing instance you specify. |
ttl number | (Optional) Sets the time-to-live (TTL) value in the IP header of the query packets. Specify a hop count from 0 through 255. The default value for local queries to the all routers multicast group is 1. Otherwise, the default value is 127. |
wait-time seconds | (Optional) Sets the time to wait for a response packet. The default value is 3 seconds. |
loop | (Optional) Loops indefinitely, displaying rate and loss statistics. To quit the mtrace command, press Ctrl-C. |
multicast-response | (Optional) Forces the responses to use multicast. |
unicast-response | (Optional) Forces the response packets to use unicast. |
no-resolve | (Optional) Does not display hostnames. |
no-router-alert | (Optional) Does not use the device alert IP option in the IP header. |
brief | (Optional) Does not display packet rates and losses. |
detail | (Optional) Displays packet rates and losses if a group address is specified. |
The following is sample output from the mtrace from-source command:
Mtrace from 192.1.4.1 to 192.1.30.2 via group 224.1.1.1 Querying full reverse path... * * 0 ? (192.1.30.2) -1 ? (192.1.30.1) PIM thresh^ 1 -2 routerC.mycompany.net (192.1.40.2) PIM thresh^ 1 -3 hostA.mycompany.net (192.1.4.1) Round trip time 22 ms; total ttl of 2 required. Waiting to accumulate statistics...Results after 10 seconds: Source Response Dest Overall Packet Statistics For Traffic From 192.1.4.1 192.1.30.2 Packet 192.1.4.1 To 224.1.1.1 v __/ rtt 16 ms Rate Lost/Sent = Pct Rate 192.168.195.37 192.1.40.2 routerC.mycompany.net v ^ ttl 2 0/0 = -- 0 pps 192.1.40.1 192.1.30.1 ? v \__ ttl 3 ?/0 0 pps 192.1.30.2 192.1.30.2 Receiver Query Source
Each line of the trace display is usually in the following format (depending on the options selected and the responses from the devices along the path):
Table 2 summarizes the output fields of the display.
 | Note: The packet statistics gathered from Juniper Networks devices and routing nodes always display as 0. |
Table 2: CLI mtrace from-source Command Output Summary
Field | Description |
|---|---|
hop-number | Number of the hop (device) along the path. |
host | Hostname, if available, or IP address of the device. If the no-resolve option was entered in the command, the hostname is not displayed. |
ip-address | IP address of the device. |
protocol | Protocol used. |
ttl | TTL threshold. |
Round trip time milliseconds ms | Total time between the sending of the query packet and the receiving of the response packet. |
total ttl of number required | Total number of hops required to reach the source. |
Source | Source IP address of the response packet. |
Response Dest | Response destination IP address. |
Overall | Average packet rate for all traffic at each hop. |
Packet Statistics For Traffic From | Number of packets lost, number of packets sent, percentage of packets lost, and average packet rate at each hop. |
Receiver | IP address receiving the multicast packets. |
Query Source | IP address of the host sending the query packets. |
