Asynchronous Transfer Mode
Asynchronous Transfer Mode |
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One of the most common sources of problems in ATM function is during the initialization of a new ATM client. Most commonly, the problem stems from an inability of the LANE client to find the LECS. There are a number of possible reasons why: the LANE services are not enabled on the switch, the LEC is attempting to join an ELAN that does not exist, or the LEC specifies parameters for an ELAN it wants to join that the switch does not support. Each of these is examined in more detail below.
If the switch's LANE services are not enabled, the ATMADM -C utility shows outgoing cells incrementing slowly. The same utility shows an attempt to contact the switch on the VPI/VCI pair 0/17. If the LEC is specifying a bad ELAN name in its attempt to join the network, the attempt to contact the switch generates a message in the Event Log. If the LANE services are not enabled on the switch, the Event Log contains no such a message.
For more information about troubleshooting connection failures, see "ATMADM Utility" earlier in this chapter.
The QoS levels on the switch do not have any affect on UBR traffic unless traffic shaping is in effect on the switch. You might notice that your connection has different up and down rates, or per VC bandwidth is much lower than the overall bandwidth of the connection. This can result in a loss of connections that would otherwise have gone through. To correct the problem, you must change the QoS parameters at the switch. See the manufacturer for details.