Topology: NE20――8*2M―transmission device―8*2M――NE40-4――Eudemon200――INTERNET
Problem Description: NE20 attached users access network and the speed is not normal. Sometimes it can ping through DNS. Sometimes there is delay and many dropped packets. Even the webpage cannot be opened.
1. Carefully check port information and inquire device information and there is no loop.
2. Bind and undo bind of eight El frequently and it is still problematic.
3. Check every E1 port and it is found no CRC.
4. Upgrade NE40 to control version 2315SP09 (It can solve the anormalness of the service when the link changes over frequently and the traffic is large.) It is still problematic.
5. Check the interface of NE20 and NE40. One is master ans another is slave. Change E1 interface of two devices as slave clock. The link is stable and the problem is solved.
1. There is loop on Eight El 8.
2. Eight E1 need undo-bind and then re-bind.
3. NE40 is based on traffic forwarding and uses poll. It forwards packets with E1. It is possible that the version does not support eight E1. When the link changes over frequently and the traffic is large, it maybe abnormal.
4. The instability of link quality results in the anormalness of the service.
5. The clock setting is problematic.
When E1/cE1 interface acts as synchronized interface, there is DTE and DCE. It need choose clock mode.
E1/cE1 interface can choose two modes: ①master clock mode: use internal clock signal. ②slave clock mode: use line signal.
When E1/cE1interfaces of two routers are connected directly, one port is Master and another is Slave.
When E1/cE1interface of the router connects transmission device, E1/cE1 as slave clock and use clock signal of transmission device.