From: k c (jwongccie@yahoo.com.hk)
Date: Wed May 04 2005 - 12:48:24 GMT-3
Hi Group,
I always find that multicast is a different topic to understand.
A very simple scenario: R1 is hub, two spokes R2 and R3, R5 connected to R2. All FR use main interfaces:
R1
/ \
R5--R2 R3
I configured sparse mode and static RP on each router. RP is R1 (172.16.1.1). All routers configured R1 as RP statically.
R1, R2 and R3's lo interface join group 230.30.30.30 (no ip pim sparse configured in all lo interfaces)
Ping 230.30.30.30 from R5, sometimes I obtained responses from all 3 routers, sometimes I obtained responses only from R1 and R2. And even from R2 only.
R5-r4#ping 230.30.30.30
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 230.30.30.30, timeout is 2 seconds:
Reply to request 0 from 172.16.25.2, 4 ms
Reply to request 0 from 172.16.123.1, 256 ms
Reply to request 0 from 172.16.123.1, 240 ms
Reply to request 0 from 172.16.123.1, 228 ms
R5-r4#
R5-r4#ping 230.30.30.30
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 230.30.30.30, timeout is 2 seconds:
Reply to request 0 from 172.16.25.2, 4 ms
Reply to request 0 from 172.16.123.3, 100 ms
Reply to request 0 from 172.16.123.3, 88 ms
Reply to request 0 from 172.16.123.1, 72 ms
Reply to request 0 from 172.16.123.3, 60 ms
Reply to request 0 from 172.16.123.1, 48 ms
Reply to request 0 from 172.16.123.1, 32 ms
After clear ip mroute on R1.
ping 230.30.30.30 from R5 cannot get response from R3.
After a few minutes latter.
ping 230.30.30.30 from R5 cannot get response from R1 and R3.
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 230.30.30.30, timeout is 2 seconds:
Reply to request 0 from 172.16.25.2, 4 ms
At this moment, R1's mroute table:
(*, 230.30.30.30), 00:04:57/stopped, RP 172.16.1.1, flags: SL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Serial5/0, 172.16.123.2, Forward/Sparse, 00:04:08/00:03:18
(172.16.25.5, 230.30.30.30), 00:04:57/00:01:06, flags: PLT
Incoming interface: Serial5/0, RPF nbr 172.16.123.2
Outgoing interface list: Null
(*, 224.0.1.40), 00:05:02/00:03:25, RP 172.16.1.1, flags: SJCL
Incoming interface: Null, RPF nbr 0.0.0.0
Outgoing interface list:
Serial5/0, 172.16.123.2, Forward/Sparse, 00:04:06/00:03:19
Serial5/0, 172.16.123.3, Forward/Sparse, 00:05:00/00:03:24
A few minutes latter, only get response from R2 and R3, not R1
R5-r4#ping 230.30.30.30
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 230.30.30.30, timeout is 2 seconds:
Reply to request 0 from 172.16.25.2, 8 ms
Reply to request 0 from 172.16.123.3, 64 ms
R1:
interface Loopback1
ip address 172.16.1.1 255.255.255.0
interface Loopback10
ip address 172.16.10.1 255.255.255.0
ip igmp join-group 230.30.30.30
interface Serial5/0
ip address 172.16.123.1 255.255.255.0
ip pim nbma-mode
ip pim sparse-mode
ip pim rp-address 172.16.1.1
R2:
interface Loopback1
ip address 172.16.20.5 255.255.255.252
ip igmp join-group 230.30.30.30
interface Serial4/0
ip address 172.16.123.2 255.255.255.0
ip pim sparse-mode
interface FastEthernet2/0
ip address 172.16.25.2 255.255.255.0
ip pim sparse-mode
ip pim rp-address 172.16.1.1
R3:
interface Loopback1
ip address 172.16.30.3 255.255.252.0
ip igmp join-group 230.30.30.30
interface Serial2/0
ip address 172.16.123.3 255.255.255.0
ip pim sparse-mode
ip pim rp-address 172.16.1.1
R5:
interface FastEthernet0/0
ip address 172.16.25.5 255.255.255.0
ip pim sparse-mode
ip pim rp-address 172.16.1.1
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This archive was generated by hypermail 2.1.4 : Fri Jun 03 2005 - 10:11:56 GMT-3