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The customer carries out network cutover, and the whole network equipment is transformed into Huawei NE40E equipment through Huawei transmission network, the web page can not be opened, while Huawei NE40E equipment through ZTE transmission network, the web page can be opened normally.
Description of network transmission:
Upper-layer server-CE(Beijing)------(MPLS+VPN)NE40(Beijing PE)-------(hereinafter referred to as the equipment in Jilin Province)--- NE40(P)------NE40(P)----Huawei SDH-EGS4------ NE40(P)----NE40(PE) ( MPLS+VPN)----- Cisco switch (CE)-----PC terminal
Alarm informationThere are no abnormal alarms for transmission devices, and no abnormal alarms for NE40E devices.
Processing Procedure1. query the optical power of the docked Huawei NE40E equipment, and rule out the optical power problem;
2. query the operating modes of the docked optical ports, and rule out the operating mode problem;
3. query the cross-connection configuration of the OSN 3500 equipment, and rule out the cross-connection error;
4. check the alarms of the NE40E and the OSN 3500 equipment, and find that there are no abnormal alarms;
5. because the customer side of the OSN 3500 does not involve the problem of overhead bytes when docking with the NE40; 6. connect the NE40E equipment to the NE40E , and then connect the NE40E to the NE40E . Because the OSN 3500 customer side does not involve overhead bytes when docking with the NE40;
6. After connecting the NE40E to ZTE's transmission equipment, the customer can access the web page normally, and all of the transmission equipment through Huawei is not available, so it can be judged to be a common problem, and check the difference between Huawei equipment and ZTE equipment, only ZTE's maximum frame length is 9600, and Huawei's EGS4 single board has a default frame length of 1522;
7. The MTU of NE40-X8 is 1500, which does not contain Layer 2 headers and MPLS labels. Since the scenario is mpls vpn via cross-domain OPTION C. Then the maximum TCP message with Layer 3 IP header + Layer 2 header goes out with the size of 1460 load + 20 tcp header + 20 ip header + two layer label 8 mpls header + 14 Ethernet header + 4 bytes of CRC = 1526. The MTU of the transmission corresponds to 1522 due to the fact that the The transmitted MTU value is less than the MTU of the actual bearer router, so it cannot be transmitted, resulting in the service not being opened.
8. Modify the maximum frame length of the EGS4 board of the transmission OSN 3500 device to 1526, and test again, the service is normal, and the web page can be opened.
Root Cause Solution2. Failure of the optical fiber;
3. Failure of the line board leading to service interruption;
4. Mismatch of the working modes of the Ethernet port;
5. Mismatch of the TAG attributes of the Ethernet port and the peer device;
6. Mismatch of the maximum frame length of the Ethernet port and the peer device;
7. Service interruption caused by the error of the cross-bonding;
8. Service interruption or packet loss caused by inconsistency in the protocols of encapsulation of Ethernet ports ; 9. Mismatch in the parameter settings of the GFP encapsulation leading to service interruption or packet loss; 10. Service interruption or packet loss due to inconsistent Ethernet port encapsulation protocols ;
9. Service interruption or packet loss due to inconsistent GFP encapsulation parameter settings;
10. Inconsistent time slot numbering strategies, there are currently two time slot numbering strategies: sequential and interpolated, and Huawei's equipment adopts sequential time slot numbering strategies by default;
11. Mismatch between J1 and C2 overhead bytes of the interfacing equipment, which results in the transmission board reporting AU_AIS alarms continuously. Therefore, you need to pay attention to the consistency of the overhead byte settings when docking;
Recommendations and Summary1. The MTU of Huawei routers refers to the IP header and its upper-layer data portion, which is the length of the IP packet, excluding the frame header and frame tail.
2. The MTU of the transmission device port refers to the maximum frame length (MFL: Maximum Frame Length). (RFC1042 based on 802.3 definition of maximum frame length: IEEE 802.3 networks have a maximum packet size which depends on the transmission rate. For type 10BASE5 802.3 networks the maximum packet size is 1518 octets. For type 10BASE5 802.3 networks the maximum packet size is 1518 octets including all octets between the destination address and the FCS inclusive.) Referring to 802.1q, the product sets the maximum frame length of the interface as For this faulty network, when transmitting SDH-EGS4 without VLAN tag and setting the MTU of the router to 1500, the maximum frame length of the transmitting device = 1500 bytes (IP header MTU) + 8 bytes (double-layer MPLS header) + 14 (bytes Ethernet header) + 4 bytes (FCS) = 1526 bytes. 1526 bytes.
3. Under the networking condition of router and transmission equipment, ping big packet can not get through, which may lead to some web pages can not be opened, and the message of some web pages may be bigger when you open the web page. It is recommended to solve the problem of ping big packet not being able to get through first, that is, adjust the MTU of the transmission device first.
4. For the handling of device docking problem, first check whether there is no problem in the basic configuration of the device, then check whether there is any abnormal alarm of the device, and finally, according to the special situation, check the overhead configuration of the device and the problem of the MTU configuration.
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