Hi,
I am trying to use IPSLA to generate a test feed between 2 cisco CE routers (hostnames R15 and R7) which are connected over a Layer 3 VPN MPLS network but i am getting some unexpected results with IPSLA yet with an ICMP ping to the multicast address it works ok.
R15#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 192.168.15.1 YES NVRAM up up
FastEthernet0/1 172.30.30.137 YES NVRAM up up
Loopback0 172.30.30.15 YES NVRAM up up
R7#sh ip int brief
Interface IP-Address OK? Method Status Protocol
FastEthernet0/0 unassigned YES NVRAM administratively down down
FastEthernet0/1 192.168.7.7 YES NVRAM up up
Serial0/0/0:1 172.30.30.122 YES NVRAM up up
Loopback1 172.30.30.7 YES NVRAM up up
Loopback7 10.10.7.1 YES manual up up
R7 (test receiver) is configured with "ip igmp join-group 228.88.88.88" under its FastEthernet0/1 interface and also set as "ip sla monitor responder".
R7#sh run | inc igmp|sla
ip sla monitor responder
ip igmp join-group 228.88.88.88
R15 (test sender) is configured with an IPSLA UDP echo probe sending traffic to multicast address 228.88.88.88 as follows:
R15#sh run | b ip sla
ip sla 1
udp-echo 228.88.88.88 65500 source-ip 172.30.30.15
timeout 100
frequency 5
ip sla schedule 1 life forever start-time now
The IPSLA probe is reporting "No connection" and no successes:
R15#sh ip sla statistics 1
Round Trip Time (RTT) for Index 1
Latest RTT: NoConnection/Busy/Timeout
Latest operation start time: 15:19:44.332 CET Fri Jul 20 2012
Latest operation return code: No connection
Number of successes: 0
Number of failures: 56
Operation time to live: Forever
Yet when testing this with a standard ICMP ping it works ok and the remote router (R7) where the IGMP join is applied responds:
R15#ping 228.88.88.88 source 172.30.30.15
Type escape sequence to abort.
Sending 1, 100-byte ICMP Echos to 228.88.88.88, timeout is 2 seconds:
Packet sent with a source address of 172.30.30.15
Reply to request 0 from 172.30.30.122, 8 ms
Reply to request 0 from 172.30.30.122, 8 ms
So i am trying to figure out why the IPSLA is failing but the ICMP ping fails......?
When applying debug ip packet & mpacket on R15 (test sender) i see the UDP echos being generated to destination address 228.88.88.88 but for some reason i see the destination UDP port as being 1967 and not 65500 as i had configured in my SLA probe:
Jul 20 13:38:04: IP: s=192.168.15.1 (local), d=228.88.88.88 (FastEthernet0/0), len 80, sending broad/multicast
Jul 20 13:38:04: UDP src=58867, dst=1967
Jul 20 13:38:04: IP: s=172.30.30.137 (local), d=228.88.88.88 (FastEthernet0/1), len 80, sending broad/multicast
Jul 20 13:38:04: UDP src=58867, dst=1967
Jul 20 13:38:04: IP: s=172.30.30.15 (local), d=228.88.88.88 (Loopback0), len 80, sending broad/multicast
Jul 20 13:38:04: UDP src=58867, dst=1967
When applying debug ip packet & mpacket on R7 (test receiver) i do see the multicast packets inbound from R15 which are generated by the IPSLA probe:
R7#
Jul 20 13:27:04.365: IP(0): MAC sa=*HDLC* (Serial0/0/0:1)
Jul 20 13:27:04.365: IP(0): IP tos=0x0, len=80, id=0, ttl=252, prot=17
Jul 20 13:27:04.365: IP(0): s=172.30.30.137 (Serial0/0/0:1) d=228.88.88.88 (FastEthernet0/1) id=0, ttl=252, prot=17, len=80(80), mforward
Jul 20 13:27:04.365: IP(0): MAC sa=*HDLC* (Serial0/0/0:1)
Jul 20 13:27:04.365: IP(0): IP tos=0x0, len=80, id=0, ttl=251, prot=17
Jul 20 13:27:04.365: IP(0): s=172.30.30.15 (Serial0/0/0:1) d=228.88.88.88 (FastEthernet0/1) id=0, ttl=251, prot=17, len=80(80), mforward
Jul 20 13:27:09.369: IP(0): MAC sa=*HDLC* (Serial0/0/0:1)
Periodically on R7 (test receiver) i also see IP socket 65500 as open then shortly after closed which is the port configured in my IPSLA probe on R15 (test sender):
R7#sh ip sockets
Proto Remote Port Local Port In Out Stat TTY OutputIF
17 --listen-- 172.30.30.7 1985 0 0 1 0
17 --listen-- 224.0.1.40 496 0 0 61 194
17 0.0.0.0 0 172.30.30.7 1967 0 0 211 0
17 --listen-- 172.30.30.7 123 0 0 1 0
R7#sh ip sockets
Proto Remote Port Local Port In Out Stat TTY OutputIF
17 --listen-- 172.30.30.7 1985 0 0 1 0
17 --listen-- 224.0.1.40 496 0 0 61 194
17 0.0.0.0 0 172.30.30.7 1967 0 0 211 0
17 --listen-- 172.30.30.7 123 0 0 1 0
17 0.0.0.0 0 228.88.88.88 65500 0 0 41 0 <<<<
Can anyone give me an idea of why this IPSLA probe may report as No connection?
Thanks
