Chapter 10: Troubleshootingcommand could instruct a converter configured in C-Bit DS3 framing mode to send FEACloopback commands to a remote converter:▪ snmpset -v 1 -c public .1.3.6.1.2.1.10.30.5.1.7.6 i 2(.6 is DS3 Port 2; .5 would be DS3 Port 1; dsx3SendLineCode(2) initiates FEAC loop cmd)▪ snmpset -v 1 -c public .1.3.6.1.2.1.10.30.5.1.7.6 i 4(sends FEAC disable loopback as in dsx3SendResetCode(4) NOT dsx3SendNoCode(1))▪ snmpset -v 1 -c public .1.3.6.1.2.1.10.30.5.1.7.6 i 1(Does nothing! Dsx3SendNoCode(1) will not terminate a loopback set up with a FEACloopback request, just stop sending a request to begin one. Use dsx3SendResetCode(4))▪ snmpget -v 1 -c public .1.3.6.1.2.1.10.30.5.1.7.6(returns current value for DS3 Port 2)· Upon successful loopback initiation, the web management status screen of the converter willalso indicate that a DS3 line is in loopback and testing administrative mode.· VACM Settings for SNMP DS3 MIB access: The SNMP area of the web managementconfiguration screen of the converter allows an operator to grant write-access to specificSNMP MIB variables. Press “Login to view sensitive SNMP community/securityinformation” then add the following line exactly (or a more secure one):authcommunity read,write public default .1.3.6.1.2.1.10.30.5.1to the “Access Rights – snmpd.conf ” section, submit changes, and confirm error-free in the“Status – snmpd.conf ” section. Remember to remove this line when done testing to maintaina completely secure system. This enables the configuration and loopback sections of the DS3MIB using community name public for all IP hosts.PerformancePerformance issues are addressed in the previous chapter.InteroperabilityThe interoperability section of this manual should be reviewed to ensure that appropriate equipment isconnected to the converter. Connected LAN equipment should adhere to 802.3 standards, and connectedtelecom equipment should be in unchannelized mode, i.e., not broken into T1 or E1 channels.Laboratory TestingThe PPPoE connection to a converter may be tested before introducing a complicated E3 or T3/DS3 link.The DS3 link does not have to be present to confirm a successful PPPoE connection via the LAN port andthe status and log messages of the converter's HTTP interface.PingingPing is not reliable. The protocol which ping programs use does not guarantee delivery of the datapackets. Ping programs from major software and hardware corporations are known to contain bugs,both in packet content and function. Generally, however, nearly all of the ping packets on a test networkthat is not over-loaded should get through; if fewer are received, there is probably a problem.The ping program is a useful, simple test for a TCP/IP Ethernet network. It is a program that sends a datapacket from a source machine to a destination machine, which then returns a response packet. There is aplethora of information about ping and the free public-domain ping utilities available. Ping is oftensupplied as a standard operating system utility, and often the command “ping” followed by the destinationmachine's IP address or hostname is all that is required to be typed at the source machine's command line.The default ping generates approximately one 64-byte packet per second. This is not a robust test. Ifconvenient, locate a ping program or set command line parameters to generate perhaps 50 pings per secondand try both small packets and large 1400-byte packets. Be aware that packets larger than 1400 bytessometimes uncover bugs in the software of ping programs.21
