diff options
Diffstat (limited to 'usr.sbin/mrouted/mtrace.8')
| -rw-r--r-- | usr.sbin/mrouted/mtrace.8 | 10 |
1 files changed, 6 insertions, 4 deletions
diff --git a/usr.sbin/mrouted/mtrace.8 b/usr.sbin/mrouted/mtrace.8 index f4d1a44..e95b59d 100644 --- a/usr.sbin/mrouted/mtrace.8 +++ b/usr.sbin/mrouted/mtrace.8 @@ -64,8 +64,9 @@ .Sh DESCRIPTION Assessing problems in the distribution of IP multicast traffic can be difficult. -.Nm Mtrace -utilizes a tracing feature implemented in multicast routers that is +The +.Nm +utility utilizes a tracing feature implemented in multicast routers that is accessed via an extension to the IGMP protocol. A trace query is passed hop-by-hop along the reverse path from the .Ar receiver @@ -212,7 +213,7 @@ seconds (default 3 seconds). .Ss "How It Works" The technique used by the .Nm traceroute -tool to trace unicast network paths will not work for IP multicast +utility to trace unicast network paths will not work for IP multicast because ICMP responses are specifically forbidden for multicast traffic. Instead, a tracing feature has been built into the multicast routers. This technique has the advantage that additional information about @@ -331,8 +332,9 @@ will try to query the next hop router with a DVMRP_ASK_NEIGHBORS2 request (as used by the .Nm mrinfo program) to see what kind of router it is. +The .Nm -will try to query three (changed with the +utility will try to query three (changed with the .Fl e option) hops past a non-responding router, in the hopes that even though it isn't capable of sending a response, it might be capable of |
