Traces multicast traffic from the receiver back to the source.
| src_address | Specifies the unicast IP address of the multicast source. |
| dest_address | Specifies the unicast IP address of the multicast group receiver. |
| grp_address | Specifies the multicast IP address of the group. |
| from_address | Specifies the unicast IP address of the interface where the mtrace request originates. This is used as the IP destination address of the mtrace response packet. |
| gw_address | Specifies the gateway router IP address of the multicast router to which the unicast mtrace query is sent. |
| seconds | Specifies a maximum time to wait for the mtrace response before making the next attempt. The range is 1–30 seconds. |
| number | Specifies the maximum number of hops for the trace. The range is 1 to 255. |
| router-alert | Specifies whether the router-alert option is included or excluded in mtrace packets. |
| vrname | Specifies a VR name. |
destination: IP address of interface from which mtrace query is generated.
group: 0.0.0.0
from: IP address of interface from which mtrace query is generated.
gateway: 224.0.0.2 when the destination is in the same subnet as one of the IP interfaces. For a non-local destination address, it is mandatory to provide a valid multicast router address.
timeout: 3 seconds
maximum-hops: 32
router-alert: include
vr: DefaultVR
The multicast traceroute initiator node generates a multicast query and waits for timeout period to expire. If there is no response for the timeout period, the initiator node makes two more attempts. If no response is received after three attempts, the initiator node moves to a hop-by-hop trace by manipulating the maximum hop fields to perform a linear search.
The multicast trace response data contains the following fields:
Extreme Networks switches set the packet count statistics field to 0xffffffff to indicate that this field is not supported.
The last column of the mtrace command output displays forwarding codes, which are described in the following table.
| Forwarding Code | Description |
|---|---|
| Wrong interface | mtrace request arrived on an interface to which this router would not forward for this source and group. |
| Prune sent upstream | This router has sent a prune request upstream for the source and group in the mtrace request. |
| Output pruned | This router has stopped forwarding for this source and group in response to a prune request from the next hop router. |
| Hit scope boundary | The group is subject to administrative scoping at this hop. |
| No route | This router has no route for the source or group and no way to determine a potential route. |
| Wrong Last Hop | This router is not the proper last-hop router. |
| Not forwarding1 | This router is not forwarding for this source and group on the outgoing interface for an unspecified reason. |
| Reached RP/Core | Reached rendezvous point or core. |
| RPF Interface | mtrace request arrived on the expected RPF interface (upstream interface) for this source and group. |
| Multicast disabled | mtrace request arrived on an interface which is not enabled for multicast. |
| Info. Hidden1 | One or more hops have been hidden from this trace. |
| No space in packet | There was not enough room to insert another response data block in the packet. |
| Next router no mtrace1 | The previous hop router does not understand mtrace requests. |
| Admin. Prohibiteda | mtrace is administratively prohibited. |
The following command initiates an mtrace for group 225.1.1.1 at IP address 1.1.1.100:
Switch.6 # mtrace source 1.1.1.100 group 225.1.1.1 Mtrace from 1.1.1.100 to Self via 225.1.1.1 0 34.2.2.4 -1 34.2.2.4 PIM thresh^ 0 1.1.1.100/32 RPF Interface -2 34.2.2.3 PIM thresh^ 0 1.1.1.100/32 -3 23.1.1.2 PIM thresh^ 0 1.1.1.100/32 -4 2.2.2.1 PIM thresh^ 0 1.1.1.100/32 Round trip time 9 ms; total ttl of 4 required.
This command was first available in ExtremeXOS 12.4.
The router-alert option was added in ExtremeXOS 12.5.3.
This command is available on platforms that support the appropriate license. For complete information about software licensing, including how to obtain and upgrade your license and which licenses support the IPv4 multicast feature, see the Switch Engine v33.1.1 Licensing Guide document.