Two routers are connected by E1 lines of E1-F module. Ping the direct-connecting address mutually, with packet loss rate of 30%.
1. Make sure it is framed at boths sides
2. Both sides enable no crc-4;
3. Make sure the transmission has clock;
4. Both sides use E1 2M lines, with the same time-slot;
5. By checkup for resistance, it is found that what has been used is 120Ohm cable, but that of the module is 75Ohm;
6. After changing the resistance, no packet is lost in mutual Ping.
Resistance does not match is responsible for packet loss in Ping process.
For E1 line interconnection, the following should be noted when packet loss occurs or link layer is DOWN:
1. Check if the frame format is identical at both sides. The E1-F module is defaulted to framed;
2.Check if both sides enable crc-4, keeping both consistent;
3. If it is in CE1 mode, check if the time slot is identical;
4. Make sure if the transmission has provided clock; if not, it needs to set the clock at one router to master, serving the whole link;
5. Check if resistance is matched correctly.