IP SLA Configuration 800 Series Routers

ChrisB · ‎12-15-2009

Hi,

I'm trying to setup some IP SLA monitoring for some links which carry VoIP traffic. As a brief network overview:

Central Site - 878 SDSL Router - 12.3(8r) - Internal IP (VLAN for all Ethernet ports) - 192.168.10.1

Remote Site A - 837 ADSL Router - 12.4(15)T6 - Internal IP (VLAN) - 192.168.20.1

Remote Site B - 837 ADSL Router - 12.3(8r) - Internal IP (VLAN) - 192.168.30.1

The routers are effectively in a triangle, with an IPSEC tunnel established between all three sites. The tunnels are up and working - VoIP traffic is passing between sites and from an SSH session on each router, I can ping the internal IP of the other routers. I have managed to succesfully establish an SLA icmp-echo check going from the central 878 to 192.168.20.1 (837 @ Site A). That is working fine and generating statistics for me.This is my IOS code:

ip sla 1
icmp-echo 192.168.20.1 source-interface Vlan1
tag Latency to MD

I now want to use SLA to monitor VoIP jitter / call quality between the sites. On central 878, I have this code:

ip sla 2
udp-jitter 192.168.20.1 16384 source-ip 192.168.10.1 source-port 16384 codec g711alaw

tag Newcastle to MD g711alaw CODEC
frequency 180
ip sla schedule 2 life forever start-time now
ip sla 3
udp-jitter 192.168.30.1 16386 source-ip 192.168.10.1 source-port 16386 codec g711alaw
tag Newcastle to Newport g711alaw CODEC
frequency 180
ip sla schedule 3 life forever start-time now

837 at Site A (192.168.20.1):

ip sla responder
ip sla responder udp-echo ipaddress 192.168.20.1 port 16384
ip sla responder udp-echo ipaddress 192.168.10.1 port 16384

Should the ip sla responder be configured with the IP address of the router it is running on or the IP address of the router which is running the sla? The documentation I've found doesn't make that clear, hence trying with both local and remote IP addresses in the configuration. This is the output from show ip sla responder:

drayton#show ip sla responder
IP SLAs Responder is: Enabled
Number of control message received: 68 Number of errors: 0
Recent sources:
        192.168.10.1 [15:11:04.255 PCTime Tue Dec 15 2009]
        192.168.10.1 [15:08:04.220 PCTime Tue Dec 15 2009]
        192.168.10.1 [15:05:04.273 PCTime Tue Dec 15 2009]
        192.168.10.1 [15:02:04.327 PCTime Tue Dec 15 2009]
        192.168.10.1 [14:59:04.379 PCTime Tue Dec 15 2009]
Recent error sources:

udpEcho Responder:
IP Address             Port
192.168.20.1          16384
192.168.10.1          16384

So I can see this router seems to be getting SLA packets from 10.1, though these could be the icmp-echo checks rather than the jitter.

Running show ip sla stat 2 on the central 878 returns this:

newcastle#show ip sla stat 2

Round Trip Time (RTT) for       Index 2
        Latest RTT: NoConnection/Busy/Timeout
Latest operation start time: 15:11:04.212 PCTime Tue Dec 15 2009
Latest operation return code: Timeout
RTT Values:
        Number Of RTT: 0                RTT Min/Avg/Max: 0/0/0 milliseconds
Latency one-way time:
        Number of Latency one-way Samples: 0
        Source to Destination Latency one way Min/Avg/Max: 0/0/0 milliseconds
        Destination to Source Latency one way Min/Avg/Max: 0/0/0 milliseconds
Jitter Time:
        Number of Jitter Samples: 0
        Source to Destination Jitter Min/Avg/Max: 0/0/0 milliseconds
        Destination to Source Jitter Min/Avg/Max: 0/0/0 milliseconds
Packet Loss Values:
        Loss Source to Destination: 0           Loss Destination to Source: 0
        Out Of Sequence: 0      Tail Drop: 0    Packet Late Arrival: 0
Voice Score Values:
        Calculated Planning Impairment Factor (ICPIF): 0
        Mean Opinion Score (MOS): 0
Number of successes: 0
Number of failures: 19
Operation time to live: Forever

So lots of timeouts. Running show ip sla collection-stat 2 gives loads of stats but this looks to be the key:

Number of failed operations due to a Timeout: 21

For the SLA monitor from the central to site B, I get:

newcastle#show ip sla stat 3

Round Trip Time (RTT) for       Index 3
        Latest RTT: NoConnection/Busy/Timeout
Latest operation start time: 15:16:50.138 PCTime Tue Dec 15 2009
Latest operation return code: No connection
RTT Values:
        Number Of RTT: 0                RTT Min/Avg/Max: 0/0/0 milliseconds
Latency one-way time:
        Number of Latency one-way Samples: 0
        Source to Destination Latency one way Min/Avg/Max: 0/0/0 milliseconds
        Destination to Source Latency one way Min/Avg/Max: 0/0/0 milliseconds
Jitter Time:
        Number of Jitter Samples: 0
        Source to Destination Jitter Min/Avg/Max: 0/0/0 milliseconds
        Destination to Source Jitter Min/Avg/Max: 0/0/0 milliseconds
Packet Loss Values:
        Loss Source to Destination: 0           Loss Destination to Source: 0
        Out Of Sequence: 0      Tail Drop: 0    Packet Late Arrival: 0
Voice Score Values:
        Calculated Planning Impairment Factor (ICPIF): 0
        Mean Opinion Score (MOS): 0
Number of successes: 0
Number of failures: 2
Operation time to live: Forever

ip sla collection-stat 3 gives:

Number of failed operations due to a No Connection: 21

Checking the ip sla responder at site B gives:

newport#show ip sla responder
IP SLAs Responder is: Enabled
Number of control message received: 0 Number of errors: 0
Recent sources:
        192.168.10.1 [11:44:34.987 PCTime Tue Dec 15 2009]
        192.168.10.1 [11:43:35.001 PCTime Tue Dec 15 2009]
        192.168.10.1 [11:42:35.015 PCTime Tue Dec 15 2009]
        192.168.10.1 [11:41:35.028 PCTime Tue Dec 15 2009]
        192.168.10.1 [11:40:35.041 PCTime Tue Dec 15 2009]
Recent error sources:

udpEcho Responder:
IP Address             Port
192.168.30.1           5000
192.168.30.1          16386
192.168.10.1          16386

So that's not seeing packets from jitter monitor.

In summary, the problem is:

SLA Jitter from Central to A = timeout

SLA Jitter from Central to B = no connection

Where am I going wrong?

Thanks,

Chris.

Eugene Khabarov · ‎12-20-2009

Configure the switch as an IP SLAs responder.

The optional keywords have these meanings:

•tcp-connect—Enable the responder for TCP connect operations.

•udp-echo—Enable the responder for User Datagram Protocol (UDP) echo or jitter operations.

•ipaddress ip-address—Enter the destination IP address.

•port port-number—Enter the destination port number.

Note The IP address and port number must match those configured on the source device for the IP SLAs operation.

So the ip sla responder should be configured with the IP address of the router which is running the sla.

do you have any ACLs on you interfaces? Maby ACL filter out you udp jitter packets.

Please rate if this helps,

Eugene.

visalini_k_1000 · ‎01-03-2014

Hi Chris

I'm not here to answer your question

but to thank you

Your query has my answer which i had been searching for weeks

Nice for sharing your query