Slow Download Speed

Publication Date:  2012-07-27 Views:  703 Downloads:  0
Issue Description
At an office, all the users of an MA5200F feed back their extremely slow online speed. For users with the 10M CAR, the download speed is only 20 to 30KBps. After you remove the MA5200 and connect the users directly to the layer-3 switch above the MA5200, the download speed is up to 800 to 900KBps. During the test, the user employs the same equipment with fixed IP address and same software to download from the same website.
Alarm Information
Handling Process
1) Seen from the problem description, when the user employs the same equipment and same software to visit the same website in the same access mode for download comparison test, the speed of the users connected to the layer-3 switch above the MA5200 is much faster than that of the users connected to the MA5200. In addition, all the users of the MA5200 feed back their slow download speed. Therefore, the uplink of the MA5200 or the MA5200 itself has trouble. 2) At first, it is suspected that the uplink has trouble, and check the negotiation mode of the port. [NJTT_MA5200F]display interface Ethernet 24 The current status of the Ethernet24: UP The current status of the link layer protocol: UP Description: TO-S2403H The Maximum Transmission Unit (MTU) is 1500, and the interval of the Keepalive packet is 10 seconds. No Internet address is configured. IP packet transmission frame format: PKTFMT_ETHNT_2 The hardware is the fast Ethernet 10/100Base-TX and the address is 00e0-fc1f-231E. Permit the auto-negotiation, semi-duplex and 100Mbps. Network cable type: Auto-sensing (supported by the straight through cable and crossover cable) The PPPoE server binds the No.1 virtual template in this interface. The negotiation working mode of the interface interconnecting the MA5200 and L3 switch is 100M semi-duplex. The working mode of the peer interface is queried to be the forced 100M full-duplex, so the working mode of the MA5200 interface is modified to forced 100M full-duplex accordingly by the following commands: [NJTT_MA5200F]interface Ethernet 24 [NJTT_MA5200F-if-ethernet24]undo negotiation auto [NJTT_MA5200F-if-ethernet24] speed 100 [NJTT_MA5200F-if-ethernet24]duplex full The download speed of the users in the MA5200 will achieve 800 to 900KBps, consistent with that when being connected with the upper switch, and the problem is solved.
Root Cause
The most common reasons for slow download speed of the users are: 1) The port negotiations are inconsistent. 2) Link quality problem, the port receiving/transmitting has a large number of wrong packets. 3) CAR limitation, including the CAR limitation of other equipment on the link. 4) Client problem.