N7010 originates not-null PIM-registers with TTL 0 ?

[andy!doesnt!like!uucp]

Hi Everyone

is anyone here aware about N7010 with 6.2(20) behavior of originating not-null PIM register packets with TTL 0 ? with capturing on upstream switch & ethanalyzing  on the affected N7K i can confirm the not-null PIM register packets don't leave chassis whilst 'debug ip pim data-register send'  shows the packets are generated & sent with TTL 0.

019 Dec 30 14:19:18.830968 mcastfwd: libpim [7821] Sent PIM Data Register for (10.201.208.11, 239.255.255.250) to RP 192.168.160.255, ttl 0 (2 registers in last sec)
2019 Dec 30 14:19:18.934952 mcastfwd: libpim [7821] Sent PIM Data Register for (10.201.208.11, 239.255.255.250) to RP 192.168.160.255, ttl 0 (3 registers in last sec)

[andy!doesnt!like!uucp · Accepted solution]

resolved. MC-G was generated on WLC which is unable to code TTL different from 1.

[Giuseppe Larosa]

Hello @andy!doesnt!like!uucp ,

nice to know a WLC can only generate multicast queries for  a group (S,G) only with TTL=1 we can consider it a multicast leaf or "stub" router.

On the other way the WLC on air can only play with different SSIDs but it is required to perform per SSID multicast packet egreess repliatom.

The WIFI physical media is different from a wired Vlan on a switch, it can be compared with a star topology where each device belonging to  a single SSID will recieive the nulticast stream or not.

on the other end multiple SSIDs can use the same IP subnet but different local address pools for DHCP

This should explain what you see.

Hope to help

Giuseppe

Also a WLC allows toFo  assign multiple SSIDs to same Ipv4 subnet