Cisco Systems OL-7396-01 Configuring IMA Group Link Differential Delay

21-15
ATM Switch Router Software Configuration Guide
OL-7396-01
Chapter21 Configuring IMA Port Adapter Interfaces
Configuring IMA Group Parameters
Displaying the IMA Group Interface Clock Mode Configuration
To display the IMA group transmit clock mode configuration, use the following EXEC command:
Example
The following example shows the IMA group clock mode configuration:
SwitchA# show ima interface
ATM0/0/ima1 is up
Group Index = 4
State: NearEnd = operational, FarEnd = operational
FailureStatus = noFailure
IMA Group Current Configuration:
MinNumTxLinks = 1 MinNumRxLinks = 1
DiffDelayMax = 25 FrameLength = 128
NeTxClkMode = independent(itc)
TestLink = 3 Testpattern = Not Specified
TestProcStatus = disabled GTSM change timestamp = 990427121150
IMA Link Information:
Link Physical Status NearEnd Rx Status Test Status
----- --------------- ----------------- ---------------
ATM0/0/2 up active disabled
ATM0/0/3 up active disabled
Configuring IMA Group Link Differential Delay
The transmitter on the T1/E1 IMA port adapter must align the transmission of IMA frames on all links
as shown in Figure 21-2. Alignment allows the receiver to adjust for differential delays among the
members of the IMA group. Based on this required behavior, the receiver can detect the differential
delays by measuring the arrival times of the IMA frames on each link.
The transmitting end of the IMA group connection sends cell s continuously. If there are no ATM layer
cells to send between ICP cells within an IMA frame, the transmit IMA sends filler cells to maintain a
continuous stream of cells at the physical layer.
The receiving end of the IMA group connection must allocate sufficient buffer space to compensate for
the differential delay between the member links. The maximum differential delay value configured for
the IMA group determines the size of these buffers.
To configure the maximum differential delay allowed in the IMA group, perform the fol lowing steps,
beginning in global configuration mode:
Command Purpose
show ima interface [atm card/subcard/imagroup
[detailed]]
Displays IMA group interface configuration
and status.
Command Purpose
Step1 Switch(config)# interface atm card/subcard/imagroup
Switch(config-if)#
Specifies the IMA group and enters interface
configuration mode.
Step2 Switch(config-if)# ima differential-delay-maximum
msecs
Specifies the maximum link differential delay
tolerated for the IMA group in milliseconds.
ForT1, the range is 25 to 250 milliseconds,
and for E1, the range is 25to 190 milliseconds.