Technical Documentation

mtrace from-source

Syntax

mtrace from-source source source <brief | detail><extra-hops extra-hops> <group group><interval interval> <loop><max-hops max-hops><max-queries max-queries> <multicast-response | unicast-response><no-resolve> <no-router-alert> <response response><routing-instance routing-instance-name><ttl ttl><wait-time wait-time>

Release Information

Command introduced before JUNOS Release 7.4.

Command introduced in JUNOS Release 9.0 for EX Series switches.

Description

Display trace information about an IP multicast path from a source to this router or switch. If you specify a group address with this command, the JUNOS Software returns additional information, such as packet rates and losses.

Options

brief | detail

(Optional) Display the specified level of output.

extra-hops extra-hops

(Optional) Number of hops to take after reaching a nonresponsive router. You can specify a number between 0 and 255.

group group

(Optional) Group address for which to trace the path. The default group address is 0.0.0.0.

interval interval

(Optional) Number of seconds to wait before gathering statistics again. The default value is 10 seconds.

loop

(Optional) Loop indefinitely, displaying rate and loss statistics.

max-hops max-hops

(Optional) Maximum hops to trace toward source. The range of values is 0 through 255. The default value is 32 hops.

max-queries max-queries

(Optional) Maximum number of query attempts for any hop. The range of values is 1 through 32. The default is 3.

multicast-response

(Optional) Always request the response using multicast.

no-resolve

(Optional) Do not attempt to display addresses symbolically.

no-router-alert

(Optional) Do not use the router-alert IP option.

response response

(Optional) Send trace response to a host or multicast address.

routing-instance routing-instance-name

(Optional) Trace a particular routing instance.

source source

Source hostname or address.

ttl ttl

(Optional) IP time-to-live (TTL) value. You can specify a number between 0 and 255. Local queries to the multicast group use a value of 1. Otherwise, the default value is 127.

unicast-response

(Optional) Always request the response using unicast.

wait-time wait-time

(Optional) Number of seconds to wait for a response. The default value is 3.

Required Privilege Level

view

List of Sample Output

mtrace from-source

Output Fields

Table 1 describes the output fields for the mtrace from-source command. Output fields are listed in the approximate order in which they appear.

Table 1: mtrace from-source Output Fields

Field Name

Field Description

Mtrace from

IP address of the receiver.

to

IP address of the source.

via group

IP address of the multicast group (if any).

Querying full reverse path

Indicates the full reverse path query has begun.

number-of-hops

Number of hops from the source to the named router or switch.

router-name

Name of the router or switch for this hop.

address

Address of the router or switch for this hop.

protocol

Protocol used (for example, PIM).

Round trip time

Average round-trip time, in milliseconds (ms).

total ttl of

Time-to-live (TTL) threshold.

source

Source address.

Response Dest

Response destination 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.

Query source

IP address sending the mtrace query.

Sample Output

mtrace from-source

user@host> mtrace from-source source 192.1.4.2 group 225.1.1.1 
Mtrace from 192.1.4.2 to 192.1.1.2 via group 225.1.1.1
Querying full reverse path... * * 
  0  routerA.lab.mycompany.net (192.1.1.2)
 -1  routerB.lab.mycompany.net (192.1.2.2)  PIM  thresh^ 1  
 -2  routerC.lab.mycompany.net (192.1.3.2)  PIM  thresh^ 1  
 -3  hostA.lab.mycompany.net (192.1.4.2)
Round trip time 2 ms; total ttl of 2 required.

Waiting to accumulate statistics...Results after 10 seconds:

Source        Response Dest    Overall     Packet Statistics For Traffic From
192.1.4.2 192.1.1.2    Packet      192.1.4.2 To 225.1.1.1
     v       __/  rtt    2 ms     Rate       Lost/Sent = Pct  Rate
192.1.2.1 
192.1.3.2  routerC.lab.mycompany.net 
     v     ^      ttl    2                      0/0    = --    0 pps
192.1.4.1 
192.1.2.2   routerB.lab.mycompany.net 
     v      \__   ttl    3                      ?/0            0 pps
192.1.1.2   192.1.1.2
  Receiver      Query Source

Published: 2010-04-27