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Adopt the Traffic Statistics Function to Locate the Problem of Packet Loss and Packet Forwarding Failure on the S9300

Publication Date:  2012-07-27 Views:  328 Downloads:  0
Issue Description
 Problem symptom:
BAS―(eth-trunk0)---S9306 (g1/0/1)====DSLAM---dialing user
Management IP addresses of the S9306 and DSLAM function as static users of the BAS. The S9306 and DSLAM cannot ping the BAS, but they can ping each other. 

Alarm Information

Handling Process
 The process is as follows:
1. The downstream computer connected to the DSLANM can dial in to the network, indicating that the link between the computer and the BAS is normal. Check the uplink and downlink interfaces of the S9306, and find that the number of error packets is 0.
2. Check the configuration of the S9306. The packets from the service VLAN and management VLAN are transparently transmitted and no ACL is configured. The configuration is correct.
3. The MAC address entries and ARP entries on the S9306 are learned normally. On the BAS, static users are online.
4. The S9306 supports the statistics on incoming and outgoing traffic. The Eth-Trunk also supports this function. This helps locate the problem. The details are as follows:
Define ICMP data flows sent from the BAS to the DSLAM and from the DSLAM to the BAS.
[S9306-acl-adv-3031]rule per icmp s 0 des 0
[S9306-acl-adv-3030]rule per icmp source 0 des 0
Enable the traffic statistics function, bind the traffic classifier to the traffic behavior, and define the traffic statistics policies.
[S9306-behavior-tj]statistic enable
[S9306-1-trafficpolicy-BastoDSLAM]c BastoDSLAM b tj
[S9306-1-trafficpolicy-DSLAMtoBas]c DSLAMtoBas b tj
Correctly apply the traffic statistics policies to the corresponding interfaces in the inbound or outbound direction, distribute the policy BastoDSLAM on the inbound interface connecting the S9300 and the BAS and the outbound interface connecting the S9300 and the DSLAM; distribute the policy DSLAMtoBas on the outbound interface connecting the S9300 and the BAS and the inbound interface connecting the S9300 and the DSLAM.
[S9306-1-Eth-Trunk0]traffic-policy BastoDSLAM in
[S9306-1-Eth-Trunk0]traffic-policy DSLAMtoBas out
Send five ping packets to the DSLAM from the BAS and check the traffic statistics on the S9306. It is found that the number of packets received and sent on two interfaces is 5, indicating that the forwarding on the S9306 is normal.
<RH-S9306-1> dis traffic po st int Eth-Trunk 0 out

Interface: Eth-Trunk0
Traffic policy outbound: 5to2
Rule number: 1
Current status: OK!
Board : 4
Item Packets Bytes
Matched 0 0
+--Passed 0 0
+--Dropped 0 0
+--Filter 0 0
+--URPF - -
+--CAR 0 0
Board : 5
Item Packets Bytes
Matched 5 540
+--Passed 5 540
+--Dropped 0 0
+--Filter 0 0
+--URPF - -
+--CAR 0 0
Check the BAS, and find that the BAS is abnormal. 

Root Cause
 The possible causes are as follows:
1. The link is faulty.
2. The configuration is faulty.
3. The forwarding on the S9306 is abnormal.
4. Other devices are faulty. 

 On the S9300, the statistics on incoming and outgoing packets can be taken. This helps to locate the problem.