Specifications

Installation and Configuration Activities 51
conforms to the specified in FRF.12, the frame relay forum fragmentation
implementation agreement.
There are two types of fragmentation: end-to-end and interface (or UNI/NNI).
Interface level fragmentation has not been implemented by any major FR switch
vendors and so it is not available through any FR service providers. IBM routers
implements both types of fragmentation.
You can configure the size of a fragment. Fragment sizes may vary between FR
interfaces depending on the access speed of the link and the CIR of the PVC.
Fragment sizes are not negotiated or communicated between interfaces.
The ENABLE FRAGMENTATION command enables the data frames to be
fragmented so that voice traffic and data traffic can both be supported on the
same interface. Voice traffic is not fragmented.
The fragmentation types are:
• User Network Interface (UNI)/Network to Network Interface (NNI)
• End-to-end
UNI is DTE to DCE fragmentation; NNI is DCE-to-DCE fragmentation; end-to-end
is DTE-to-DTE fragmentation over a particular specified interface. You cannot
activate fragmentation over DLCI 0.
When you select the fragmentation type, be sure that the receiving router at the
another side has the same fragmentation type.
The fragment-timer specifies the length of time in seconds that the receiver of the
fragments waits for the end fragments to arrive. If this timer expires before the
last fragment arrives, all the received fragments are discarded.
Note: You can configure fragmentation either for an interface or for a circuit. If
you configure fragmentation for a circuit, you must use the CHANGE
PERMANENT-VIRTUAL-CIRCUIT command.
At the frame relay interface, bandwidth reservation allows you to reserve
bandwidth at two levels:
FR 0 Config>ENABLE FRAGMENTATION
Specify the fragmentation type to be done [UNI/NNI Fragmentation]?
Fragment size (50 to 1000) [256]?
Fragmented packet reassembly timer (3 to 10 seconds) [3]?
FR 0 Config>CHANGE PERMANENT-VIRTUAL-CIRCUIT
Circuit number [16]?
Committed Information Rate (CIR) in bps [64000]?
Committed Burst Size (Bc) in bits [64000]?
Excess Burst Size (Be) in bits [0]?
Assign circuit name []?
Is circuit required for interface operation [N]?
Do you want end-to-end fragmentation performed on this circuit [N]? Y
Fragment size (50 to 1000) [256]?
Fragmented packet reassembly timer (3 to 10 seconds) [3]?
Enable circuit for voice forwarding [N]? N