This case introduces the triggering conditions and solutions for the problem of ONT accesses OLT multicast services.
Problem description:
The one end of the tester is connected to the LAN4 port of the 8245H to simulate the STB, and the another one end of the tester is connected to the S9303 to simulate the IPTV server. Use the tester to simulate bidirectional IP traffic and send traffic. It is found that packet loss occurs in both directions.
Networking:
Problem analysis:
To simplify the troubleshooting, only send the traffic from the STB to the IPTV server.
Traffic information: The traffic bandwidth is 10M, which is the simulated IP traffic.
1. Clear traffic statistics on the ONT ETH4, WAN, and OLT upstream port.
MA5600T(config)#reset statistics ont 0/3 0 2 //clear traffic statistic of ONT WAN
MA5600T(config)#reset statistics ont-eth 0/3 0 2 ont-port 4 //clear traffic statistic of ont-port4
MA5600T(config)#interface giu 0/19
MA5600T(config-if-giu-0/19)#reset port statistics 1 //clear traffic statistic of OLT upstream port
2. Use the tester to send traffic from the STB to the server, packet sending: 28,872packets, packet receiving: 17054packets.
3. Check traffic statistics on the ONT ETH4, WAN, and OLT upstream port.
MA5600T(config)#display statistics ont 0/3 0 2 //check traffic statistic of the ONT WAN port
MA5600T(config)#display statistics ont-eth 0/3 0 2 ont-port 4 //Check the traffic statistic of the ont-port4
MA5600T(config)#interface giu 0/19
MA5600T(config-if-giu-0/19)#display port statistics 1 //Check traffic statistic of the OLT upstream port
The command output shows that the number of ont-port4 ingress packets is 28,872, and the number of egress packets on the WAN port is 17110 packets.
According to the statistics, we can judge that the packet loss occurs on the ONT.
4. Log in to the ONT through Telnet and check the packets sent from the ONT to CP
MA5600T(diagnose)%%telnet 0/3/0 2
Login:root
Password:（admin）
Password is default value, please modify it!
WAP> chipdebug print on
Set flag of 0x0000006e to 0x00000001;
success!
WAP>
WAP>chipdebug soc tocpures
---------- tocpu reason -------------
[0] l2_wlan = 2741
[1] efc0_matched = 5344834
[16] efc15_matched = 3
[23] igmp_ipoe = 54
[24] arp = 259
[26] pppoe_dis = 2
[29] dhcp = 157
[41] tcp_ctrl = 19
[42] napt_on = 7814167
success!
Check the packets sent to the CP. It is found that the number of [42] napt_on packets is large. Determines that the forwarded packets are sent to the CP.
5. Check the packets and found which are pure IP packets. Confirm with the ONT that pure IP packets are forwarded through software on the ONT. The forwarding efficiency is low. Therefore, packet loss occurs.
Solution:
Re-edit the packet, add a UDP header to the IP packet, and re-learn ARP sending traffic. Check the packet loss does not occur on the tester. The problem is solved.
Suggestion and summary:
When using a tester to simulate services, especially for services at Layer 3 or higher, you had better to analyze the differences between simulated services and actual services. Simulate services as real as possible.
